Anali za istrske in mediteranske študije Annali di Studi istriani e mediterranei Annals for Istrian and Mediterranean Studies Series Historia Naturalis, 31, 2021, 1 UDK 5 Annales, Ser. hist. nat., 31, 2021, 1, pp. 1-164, Koper 2021 ISSN 1408-533X KOPER 2021 Anali za istrske in mediteranske študije Annali di Studi istriani e mediterranei Annals for Istrian and Mediterranean Studies Series Historia Naturalis, 31, 2021, 1 UDK 5 ISSN 1408-533X e-ISSN 2591-1783 ANNALES · Ser. hist. nat. · 31 · 2021 · 1 Anali za istrske in mediteranske študije - Annali di Studi istriani e mediterranei - Annals for Istrian and Mediterranean Studies ISSN 1408-533X UDK 5 Letnik 31, leto 2021, številka 1 e-ISSN 2591-1783 UREDNIŠKI ODBOR/ COMITATO DI REDAZIONE/ BOARD OF EDITORS: Alessandro Acquavita (IT), Nicola Bettoso (IT), Christian Capapé (FR), Darko Darovec, Dušan Devetak, Jakov Dulčić (HR), Serena Fonda Umani (IT), Andrej Gogala, Daniel Golani (IL), Danijel Ivajnšič, Mitja Kaligarič, Marcelo Kovačič (HR), Andrej Kranjc, Lovrenc Lipej, Vesna Mačić (ME), Alenka Malej, Patricija Mozetič, Martina Orlando- Bonaca, Michael Stachowitsch (AT), Tom Turk, Al Vrezec Glavni urednik/Redattore capo/ Editor in chief: Darko Darovec Odgovorni urednik naravoslovja/ Redattore responsabile per le scienze naturali/Natural Science Editor: Lovrenc Lipej Urednica/Redattrice/Editor: Martina Orlando-Bonaca Lektor/Supervisione/Language editor: Polona Šergon (sl.), Petra Berlot Kužner (angl.) 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Navodila avtorjem in vse znanstvene revije in članki so brezplačno dostopni na spletni strani https://zdjp.si/en/p/annalesshn/ The submission guidelines and all scientific journals and articles are available free of charge on the website https://zdjp.si/en/p/annalesshn/ Le norme redazionali e tutti le riviste scientifiche e gli articoli sono disponibili gratuitamente sul sito https://zdjp.si/en/p/annalesshn/ ANNALES · Ser. hist. nat. · 31 · 2021 · 1 Anali za istrske in mediteranske študije - Annali di Studi istriani e mediterranei - Annals for Istrian and Mediterranean Studies UDK 5 Letnik 31, Koper 2021, številka 1 ISSN 1408-53 3X e-ISSN 2591-1783 VSEBINA / INDICE GENERALE / CONTENTS 2021(1) BIOINVAZIJA BIOINVASIONE BIOINVASION Luca CASTRIOTA & Manuela FALAUTANO Reviewing the Invasion History of the Blue Crab Callinectes sapidus (Portunidae) in Sicily (Central Mediterranean): an Underestimated Alien Species ... Revizija zgodovine invazije modre rakovice Callinectes sapidus (Portunidae) na Siciliji (osrednje Sredozemsko morje): podcenjena tujerodna vrsta Alan DEIDUN, Bruno ZAVA, Maria CORSINI- FOKA, Johann GALDIES, Antonio DI NATALE & Bruce B. COLLETTE First Record of the Flat Needlefish, Ablennes hians (Belonidae) in Central Mediterranean Waters (Western Ionian Sea) ............................................. Prvi zapis o pojavljanju ploščate morske igle, Ablennes hians (Belonidae) v vodah osrednjega Sredozemskega morja (zahodno Jonsko morje) Mohamed Mourad BEN AMOR, Khadija OUNIFI-BEN AMOR, Marouène BDIOUI & Christian CAPAPÉ Occurrence of Reticulated Leatherjacket Stephanolepis diaspros (Monacanthidae) in the Central Mediterranean Sea, and New Record from the Tunisian coast ............. Pojavljanje afriškega kostoroga, Stephanolepis diaspros (Monacanthidae), v osrednjem Sredozemskem morju in prvi podatek za tunizijsko obalo Sara AL MABRUK, Ioannis GIOVOS & Francesco TIRALONGO New Record of Epinephelus areolatus in the Mediterranean Sea: First Record from Syria .......... Novi zapis o pojavljanju rdečepikaste kirnje (Epinephelus areolatus) v Sredozemskem morju: prvi podatki za Sirijo SREDOZEMSKI MORSKI PSI SQUALI MEDITERRANEI MEDITERRANEAN SHARKS Primo MICARELLI, Francesca Romana REINERO & Emilio SPERONE Notes on a Rare Case of Bluntnose Sixgill Shark Hexanchus griseus Stranded on the Coast of Tuscany in the Central Tyrrhenian Sea ................. Zapis o redkem primeru morskega psa šesteroškrgarja Hexanchus griseus, ki je nasedel na toskanski obali v osrednjem Tirenskem morju Alen SOLDO The Occurrence of the Common Angel Shark Squatina squatina in the Adriatic Sea ................... Pojavljanje navadnega sklata (Squatina squatina) v Jadranskem morju Hakan KABASAKAL, Deniz AYAS & Deniz ERGÜDEN Intentional Stranding of a Blue Shark, Prionace glauca (Carcharhiniformes: Carcharhinidae), in Pursuit of Prey ....................... Namerno nasedanje sinjega morskega psa, Prionace glauca (Carcharhiniformes: Carcharhinidae), med zasledovanjem plena Patrick L. JAMBURA, Julia TÜRTSCHER, Alessandro DE MADDALENA, Ioannis GIOVOS, Jürgen KRIWET, Jamila RIZGALLA & Sara A. A. AL MABRUK Using Citizen Science to Detect Rare and Endangered Species: New Records of the Great White Shark Carcharodon carcharias Off the Libyan Coast ........................ Uporaba ljubiteljske znanosti za pridobivanje podatkov o redki in ogroženi vrsti: novi podatki o pojavljanju belega morskega volka Carcharodon carcharias ob Libijski obali 51 1 9 23 37 31 17 45 ANNALES · Ser. hist. nat. · 31 · 2021 · 1 IHTIOLOGIJA ITTIOLOGIA ICHTHYOLOGY Sihem RAFRAFI-NOUIRA, Christian REYNAUD & Christian CAPAPÉ A New Record of Clinitrachus argentatus (Osteichthyes: Clinidae) from the Tunisian Coast (Central Mediterranean Sea)............................ Novi zapis o pojavljanju srebrnice Clinitrachus argentatus (Osteichthyes: Clinidae) iz tunizijske obale (osrednje Sredozemsko morje) Mauro CAVALLARO, Giovanni AMMENDOLIA, Ignazio RAO, Alberto VILLARI & Pietro BATTAGLIA Variazioni pluriennali del fenomeno dello spiaggiamento di specie ittiche nello stretto di Messina, con particolare attenzione alle specie mesopelagiche .............................................. Večletne spremembe v nasedanju ribjih vrst v Mesinski ožini s posebnim ozirom na mezopelaške vrste Sihem RAFRAFI-NOUIRA, Christian REYNAUD & Christian CAPAPÉ Skeletal and Pughead Deformities in the Saddle Bream Oblada melanura (Osteichthyes: Sparidae) from the Tunisian Coast (Central Mediterranean Sea) ... Deformacije skeleta in glave pri črnorepki, Oblada melanura (Osteichthyes: Sparidae) iz tunizijske obale (osrednje Sredozemsko morje) Murat BILECENOGLU & Seydi Ali DOYUK Uncommon Thermophilic Fishes from the Marmara and Black Seas ............................ Nenavadne toploljubne ribe iz Marmarskega in Črnega morja Christian CAPAPÉ, Adib SAAD, Ahmad SOLAIMAN, Issa BARAKAT & Waad SABOUR First Substantiated Record of Armless Snake Eel Dalophis imberbis (Osteichthyes: Ophichthidae) from the Syrian Coast (Eastern Mediterranean Sea) ... Prvi dokumentiran primer pojavljanja kačaste jegulje, Dalophis imberbis (Osteichthyes: Ophichthidae), vzdolž sirske obale (vzhodno Sredozemsko morje) Khaled RAHMANI, Fatiha KOUDACHE, Amaria Latefa BOUZIANI & Alae Eddine BELMAHI Length-Weight Relationships and Metric Characters of the Atlantic Horse Mackerel, Trachurus trachurus (Perciformes: Carangidae), Caught in Béni-Saf Bay, Western Mediterranean (Algeria) ................................ Odnos med dolžino in maso in metrični znaki navadnega šnjura, Trachurus trachurus (Perciformes: Carangidae), ujetega v zalivu Béni-Saf, zahodno Sredozemsko morje (Alžirija) Tülin ÇOKER & Okan AKYOL On the Occurrence of Pomadasys incisus (Haemulidae) in the Turkish Aegean Sea (Eastern Mediterranean Sea) ..................................... O pojavljanju vrste Pomadasys incisus (Haemulidae) v turškem Egejskem morju (vzhodno Sredozemsko morje) Sihem RAFRAFI-NOUIRA, Mohamed Mourad BEN AMOR, Khadija OUNIFI-BEN AMOR, Marouène BDIOUI & Christian CAPAPÉ First Substantiated Record of Opah, Lampris guttatus (Osteichthyes: Lamprididae), from the Tunisian Coast (Central Mediterranean Sea)........ Prvi dokumentiran zapis o pojavljanju svetlice, Lampris guttatus (Osteichthyes: Lamprididae), iz tunizijske obale (osrednje Sredozemsko morje) FLORA FLORA FLORA Claudio BATTELLI & Marcello CATRA First Report of Cystoseira aurantia (Sargassaceae, Fucophyceae) from the Lagoon of Strunjan (Gulf of Trieste, Northern Adriatic) ............................ Prvo poročilo o vrsti Cystoseira aurantia (Sargassaceae, Fucophyceae) v strunjanski laguni (Tržaški zaliv, severni Jadran) Amelio PEZZETTA Le Orchidaceae di Pinguente (Buzet)........................ Kukavičevke Buzeta FAVNA FAVNA FAVNA Ahmet ÖKTENER & Ivan SAZIMA Caligus minimus (Copepoda: Caligidae) Parasitic on the Gills of a Remora Echeneis naucrates Attached to a Seabass Dicentrarchus labrax in Köyceğiz-Dalyan Lagoon Lake, Aegean Sea, Turkey .................................................. Caligus minimus (Copepoda: Caligidae), zajedavec na škrgah prilepa (Echeneis naucrates), pritrjenega na brancina (Dicentrarchus labrax) v laguni Köyceğiz-Dalyan v Egejskem morju, Turčija Kazalo k slikam na ovitku .................................... Index to images on the cover ............................... 159 165 165 139 129 63 69 95 101 147 123 107 85 ANNALES · Ser. hist. nat. · 30 · 2020 · 1 6 Ahmet ÖKTENER & Sezginer TUNCER: OCCURRENCE OF GNATHIA LARVAE (CRUSTACEA, ISOPODA, GNATHIIDAE) IN THREE LESSEPSIAN FISH SPECIES ..., 87–98 BIOINVAZIJA BIOINVASIONE BIOINVASION ANNALES · Ser. hist. nat. · 30 · 2020 · 1 7 Ahmet ÖKTENER & Sezginer TUNCER: OCCURRENCE OF GNATHIA LARVAE (CRUSTACEA, ISOPODA, GNATHIIDAE) IN THREE LESSEPSIAN FISH SPECIES ..., 87–98 ANNALES · Ser. hist. nat. · 31 · 2021 · 1 1 received: 2020-10-27 DOI 10.19233/ASHN.2021.01 REVIEWING THE INVASION HISTORY OF THE BLUE CRAB CALLINECTES SAPIDUS (PORTUNIDAE) IN SICILY (CENTRAL MEDITERRANEAN): AN UNDERESTIMATED ALIEN SPECIES Luca CASTRIOTA & Manuela FALAUTANO ISPRA, Italian Institute for Environmental Protection and Research, Lungomare Cristoforo Colombo n. 4521 (ex complesso Roosevelt), Località Addaura, 90149 Palermo e-mail: luca.castriota@isprambiente.it ABSTRACT The alien blue crab Callinectes sapidus, a species native to the western Atlantic coasts, has long invaded the Mediterranean, including the Italian seas. It is listed among the 100 worst invasive alien species in the Mediterranean and is presumed to exert an impact on biodiversity and fishing activities. To date, a small number of individuals of this species has been reported from Sicily. This note updates the status of the species in Sicilian seas by means of an analysis of records from various sources, and adds further records. The analysis shows that the distribution of the species in Sicily has so far been underestimated both in terms of abundance and frequency of occurrence. Key words: citizen science, non-indigenous, Decapoda, Brachyura, waterways, lagoons RILEGGERE LA STORIA DELL’INVASIONE DEL GRANCHIO BLU CALLINECTES SAPIDUS (PORTUNIDAE) IN SICILIA (MEDITERRANEO CENTRALE): UNA SPECIE ALIENA SOTTOSTIMATA SINTESI Il granchio blu alieno Callinectes sapidus, una specie originaria delle coste dell’Atlantico occidentale, ha invaso da tempo il Mediterraneo, compresi i mari italiani. È elencata tra le 100 peggiori specie esotiche invasive del Mediter- raneo e si presume abbia un impatto sulla biodiversità e sulle attività di pesca. Ad oggi, solo di pochi individui è stata documentata la presenza in Sicilia. Questa nota aggiorna lo stato della specie nei mari siciliani mediante un’analisi delle segnalazioni provenienti da varie fonti e aggiunge ulteriori ritrovamenti. L’analisi mostra che la distribuzione delle specie in Sicilia è stata finora sottostimata sia in termini di abbondanza che di frequenza di ritrovamento. Parole chiave: scienza dei cittadini, specie non indigene, decapodi, brachiuri, corsi d’acqua, lagune ANNALES · Ser. hist. nat. · 31 · 2021 · 1 2 Luca CASTRIOTA & Manuela FALAUTANO: REVIEWING THE INVASION HISTORY OF THE BLUE CRAB CALLINECTES SAPIDUS (PORTUNIDAE) IN SICILY ..., 1–8 INTRODUCTION The blue crab Callinectes sapidus Rathbun, 1896 is a shelf-estuarine species native to the western Atlantic coasts, ranging from Nova Scotia in Canada down to northern Argentina, including Bermuda and the Antil- les (Williams, 1974). This species started invading the European Atlantic coasts in 1900 (Nehring, 2011 and literature therein) and was probably introduced in the Mediterranean Sea through maritime traffic. Although mistaken in the past for the Lessepsian crab Portunus segnis (Forskål, 1775), its first occurrence in the Medi- terranean can safely be dated to 1949, when a speci- men, currently preserved in the zoological collection of the Museum of Natural History of Venice, was caught in the northern Adriatic Sea (Mizzan, 1993; Castriota et al., 2012). Currently, this species has spread to many areas of the Mediterranean Sea, probably owing to its tolerance to environmental changes, high fecundity, strong swimming ability, and pugnacious nature (Wil- liams, 1974). Included among the 100 worst invasive alien species in the Mediterranean Sea (Streftaris & Zenetos, 2006), it is presumed to exert an impact on benthic communities at multiple trophic levels and to have considerable negative effects on fishing activities; on the other hand, this alien species is already a high- -value resource in some fisheries of the eastern Mediter- ranean (Mancinelli et al., 2017). The first occurrence of C. sapidus in Sicilian waters dates back to 1970 when one specimen was collected in the Strait of Messina, followed by another specimen caught in 1972 in the same area (Cavaliere & Berdar, 1975). However, these occurrences have been questioned by some authors and rather attributed to misidentification of P. segnis (Lipej et al., 2017). Recently, Falsone et al. (2020) reported new records of C. sapidus in the Strait of Sicily and provided an updated distribution map of this species’ records in the Mediterranean suggesting its successful settlement in the Strait of Sicily, despite the scarcity of valid su- pporting records. However, new reports originating from online sources (i.e., magazines) and those reported directly to the scientists, suggest that the distribution of this species in Sicilian seas as reported in the literature does not reflect the current situation but seems to be underestimated. This note aims to update the distribution of C. sapi- dus in Sicilian waters through the addition of several new records in new locations, since tracing the spre- ad of invasive species may be useful for controlling and preventing the potential adverse effects on local ecosystems. MATERIAL AND METHODS An analysis of both scientific and grey literature as well as that of other sources (i.e., online magazines, observations reported directly to scientists) was carried out in order to revise the invasion history of Callinectes sapidus in Sicilian waters and to update the knowled- ge on its current distribution in Sicily. Records were reported in chronological order on a map (Fig. 1). Published records that did not provide detailed photos or descriptions of specimens were considered uncon- firmed. Citizen reports were collected by ISPRA (Italian Institute for Environmental Protection and Research) researchers through both personal contacts and the de- dicated institutional email alien@isprambiente.it. This email address was launched in 2013 with the aim of collecting records of marine alien species in the national territory from citizens. These records were considered valid only when the reports contained details on the capture/sighting of blue crabs along with photos of the Fig. 1: Map of Sicily indicating the distribution of Cal- linectes sapidus by chronological order of occurrence, with enlargement of the south-eastern area. 1, 2: Lipej et al., 2017; 3: Guadagnino, 2016; 4–6: Katsanevakis et al., 2020; 7–8: Falsone et al., 2020; 9: Giacobbe et al., 2019; 10–12: Katsanevakis et al., 2020; 13: Pipito- ne et al., 2020; 14: Falsone et al., 2020; 15: Pipitone et al., 2020; 16: www.oggimilazzo.it 2020; 17: present paper; 18: www.tp24.it 2020; 19: Sercia & Innocenti, 2020; 20–24: present paper. Blue points are records from literature; red points are records from other sources. Sl. 1: Razširjenost modre rakovice (Callinectes sa- pidus) na podlagi zapisov v časovnem zaporedju na zemljevidu Sicilije, z razširjenim jugovzhodnim pre- delom. 1, 2: Lipej et al., 2017; 3: Guadagnino, 2016; 4–6: Katsanevakis et al., 2020; 7–8: Falsone et al., 2020; 9: Giacobbe et al., 2019; 10–12: Katsanevakis et al., 2020; 13: Pipitone et al., 2020; 14: Falsone et al., 2020; 15: Pipitone et al., 2020; 16: www.oggimilazzo. it 2020; 17: to delo; 18: www.tp24.it 2020; 19: Sercia & Innocenti, 2020; 20–24: to delo. Modre točke so podatki iz literature, rdeči pa podatki iz drugih virov. ANNALES · Ser. hist. nat. · 31 · 2021 · 1 3 Luca CASTRIOTA & Manuela FALAUTANO: REVIEWING THE INVASION HISTORY OF THE BLUE CRAB CALLINECTES SAPIDUS (PORTUNIDAE) IN SICILY ..., 1–8 specimens that allowed the identification of the species. Records from online magazines were validated through analyses of the photo/video documentation referring to the reports and directly provided by the Authors/Editors. The specimens recorded were identified to species level on the base of the presence of two large and obtuse teeth on the frontal margin, which distinguish C. sapi- dus from P. segnis, another exotic crab reported in the Mediterranean (Williams, 1974; Mizzan, 1993; Lai et al., 2010), which also occurs in Sicily either reported as P. pelagicus or misidentified as C. sapidus (Ariani & Serra, 1969). P. segnis also bears a prominent spine on the internal margin of the cheliped carpus (Lai et al., 2010), which is missing in C. sapidus. In addition, P. segnis exhibits many pale white spots on the carapace surface, particularly posteriorly and anterolaterally (Lai et al., 2010), which are absent in C. sapidus. In some cases, it was also possible to determine the sex and maturity stage through an analysis of ab- domen morphology according to Williams (1974). The approximate size of the individuals was also recorded, estimated by the person who reported them. RESULTS Literature analysis yielded 16 valid records of at least 50 individuals of Callinectes sapidus from 12 Sicilian localities (Lipej et al., 2017; Giacobbe et al., 2019; Falsone et al., 2020; Katsanevakis et al., 2020; Pipitone et al., 2020; Sercia & Innocenti, 2020), plus 3 unconfir- med records from 2 localities (Cavaliere & Berdar, 1975; Franceschini et al., 1993). Additionally, eighth records in as many locations were extracted from other sources (Tab. 1). Three of these records were retrieved through online magazines and consist of: i) one specimen spot- ted in November 2016 in the southwestern Sicilian coast (Guadagnino, 2016), subsequently also reported in the literature (Katsanevakis et al., 2020), ii) one specimen recorded in February 2020 in the northeastern coast (www.oggimilazzo.it, 2020), and iii) dozens of indivi- duals reported in June 2020 in the Stagnone di Marsala Lagoon (west coast) (www.tp24.it, 2020). Two records were personally reported to ISPRA researchers by two professional fishermen. The first fisherman reported the capture of one specimen (Fig. 2) caught on 31 March 2020, by trammel net targeting cut- tlefish Sepia officinalis, on a mixed rocky-sandy bottom at 4 m depth, 300 m far from the mouth of the Naro River in the southwestern coast of Sicily (Porto Empedo- cle). Upon photographing the specimen, the fisherman released it alive back into the sea. It was an immature female, as shown by the triangular poorly expanded abdomen (Williams, 1974), and measured about 12 cm in carapace width. At the moment of capture it exhibited the following colours: brownish green dorsally with whitish scattered dots anteriorly, white ventrally, cheli- Record number (Fig. 1) Observation date Location Coordinates (DD) Substratum Depth Sex Number of specimens 16 24/02/2020 Milazzo 38.2384°N 15.2397°E sand-gravel bottom 0-10 m male 1 17 31/03/2020 Porto Empedocle 37.231006°N 13.622655°E rocky bottom with sand 4 m immature female 1 18 01/06/2020 Stagnone di Marsala 37.8572°N 12.4595°E sand with seagrass 0-2 m - many 20 22/08/2020 Sampieri 36.720000°N 14.737306°E sand with rocks 10-15 cm - 1 21 20/09/2020 Oasi del Simeto 37.387223°N 15.082757°E - - - 5 22 18/10/2020 Sampieri quagmire 36.719778°N 14.750889°E - 0-10 cm - 1 23 19/10/2020 Marina di Modica quagmire 36.709833°N 14.782472°E - - - 3 24 17/12/2020 Sciacca 37.517078°N 12.986948°E sandy bottom 7-8 m - 1 Tab. 1: Records of Callinectes sapidus collected from online sources and citizen reports. Tab. 1: Podatki o vrsti Callinectes sapidus, zbrani iz spletnih virov in virov, povezanih z ljubiteljsko znanostjo. ANNALES · Ser. hist. nat. · 31 · 2021 · 1 4 Luca CASTRIOTA & Manuela FALAUTANO: REVIEWING THE INVASION HISTORY OF THE BLUE CRAB CALLINECTES SAPIDUS (PORTUNIDAE) IN SICILY ..., 1–8 peds orange with blue anterior sides, merus of chelipeds bearing three white spines with dark brown extremities, legs light blue. The fisherman reported damages to the net the meshes of which were cut by the crab’s claws. The second fisherman reported the capture of one specimen of about 20 cm in carapace width, caught on 17 December 2020, by trammel net on a sandy bottom at 7-8 m depth in the locality of Sciacca (southwestern coast of Sicily). This record was validated based on an analysis of a video made by the fisherman. Additional four records were reported to ISPRA rese- archers by email: on 22 August 2020, an adult specimen measuring about 20 cm in width was caught by hand net on the seashore, on a sandy bottom with rocks, in the south-eastern coast of Sicily (Sampieri), and photo- graphed; in September 2020, six specimens (Fig. 3) were poached in inland waters within the Oriented Nature Reserve Simeto Oasis in eastern Sicily, subsequently se- ized and photographed by the staff of the Reserve; on 18 October 2020, an individual of about 13 cm in carapace width was photographed at the depth of 10-15 cm on the bank of the Sampieri quagmire, south-eastern Sicily; on 19 October 2020, three individuals of different sizes, the largest of which measured about 20 cm in carapace width, were spotted in the marsh of Marina di Modica, south-eastern Sicily, and photographed. DISCUSSION The history of the invasion by Callinectes sapidus in Sicily begins with the record of a female of this species collected in the Strait of Messina in 1970, followed by the capture of another female in 1972 in the same area (Cavaliere & Berdar, 1975). These two specimens were later attributed to Portunus segnis (Lipej et al., 2017), but they are to be re-examined at the University of Messina, where they are currently preserved and waiting to be inventoried (Giacobbe et al., 2019). We have classified these individuals as unconfirmed until proven otherwise, as we did with the record from eastern Sicily, no longer verifiable, reported by Franceschini et al. (1993) in a species checklist from trawl surveys. If we exclude these unconfirmed records, the first validated record of C. sapidus in Sicily is the specimen caught in October 2016 outside the harbour of Licata (southern coast) on sandy-muddy bottom, followed by a further capture of two individuals in the same locality ten days later (Lipej et al., 2017) (Fig. 1, nos. 1, 2). About a month later, another individual was reported on a sandy bottom of the Sicilian southwestern coast (Selinunte), at about 110 km west from the first record site (Gu- adagnino, 2016) (Fig. 1, n. 3). No additional records were reported until May 2018 when this species reappeared in a few localities of the southeastern Si- cilian coast (Fig. 1, nos. 4, 5), on both muddy bottoms and sandy bottoms with sparse seagrass Posidonia oceanica; an exceptional capture of 20 individuals was reported on muddy bottoms near a river mouth on the eastern coast (Fig. 1, no. 6) (Katsanevakis et al., 2020). Subsequently, the species reappeared in some locations where it had already been recorded (Falsone et al., 2020; Katsanevakis et al., 2020) (Fig. 1, nos. 7, 8, 10, 11) and appeared for the first time in Fig. 2: Specimen of Callinectes sapidus caught at Porto Empedocle (Sicily) on 31 March 2020 (A: ventral view, B: dorsal view). Sl. 2: Primerek modre rakovice (Callinectes sapidus), ujete pri Portu Empedocle (Sicilija) 31. marca 2020 (A: trebušna stran; B: hrbtna stran). ANNALES · Ser. hist. nat. · 31 · 2021 · 1 5 Luca CASTRIOTA & Manuela FALAUTANO: REVIEWING THE INVASION HISTORY OF THE BLUE CRAB CALLINECTES SAPIDUS (PORTUNIDAE) IN SICILY ..., 1–8 new Sicilian areas such as the northeastern (Giacobbe et al., 2019) (Fig. 1, n. 9) and northwestern coasts (Katsanevakis et al., 2020; Pipitone et al., 2020) (Fig. 1, nos. 12, 13). Additional records were reported in 2020, some of them in already mentioned sites (Fal- sone et al., 2020; Pipitone et al., 2020; present paper) (Fig. 1, n. 14, 15, 20-23), others from new Sicilian areas (Sercia & Innocenti, 2020; present paper) (Fig. 1, nos. 16–19). The occurrence of C. sapidus in some of these localities was also confirmed by the results of an online questionnaire administered to recreational fishers (Cerri et al. 2020). From our revision, this spe- cies spread to almost the entire coast of Sicily over a period of four years (2016–2020), first colonising the southern coasts and then extending its distribution in other areas, without showing a well-traced path. Such a rapid spread could be related to the presence in Sicily of several lagoons and waterways connected to the sea where C. sapidus spends some phases of its life cycle. As known, C. sapidus specimens migrate from seawater to rivers, and vice versa, at different stages of their life cycle. In particular, after mating in estuarine brackish waters females migrate to higher salinity coastal waters to lay eggs and then tend to remain there, or rather move to close-by sea waters while males prefer to remain in low salinity areas (Van Engel, 1958; Williams, 1965). Larval stages complete their development in coastal waters and re-enter brackish habitats at the stage of post-larva up to reach the juvenile stage; both juvenile and adult stages can be found in freshwater areas as well as highly saline habitats (Hines et al., 2008; Mancinelli et al., 2013; Cilenti et al., 2015). According to collected data, this species in Sicilian waters predominates on soft bot- toms, mainly in proximity of river mouths or inland channels, but also in coastal lagoons and near ports, in different periods of the year, and in shallow waters. The occurrence of several C. sapidus records in the vicinity of Sicilian brackish water bodies suggests these places to be potential areas of establishment, as observed in other Mediterranean estuaries and lagoons where established populations occurred with numerous specimens at different life stages (Beqiraj & Kashta, 2010; Dulčić et al., 2011; Mancinelli et al., 2013). For this reason, it is important to monitor estuarine and lagoon areas and consider them for ma- nagement purposes in order to contain the invasion by this species and to mitigate possible impacts on biodiversity and fishing activity. C. sapidus would in fact interfere with fishing activities, on the one hand, by damaging the nets with its claws (Beqiraj & Kashta, 2010), on the other, by representing a valu- able commercial resource for its highly appreciated meat, although in Sicily the species has not yet been introduced in local markets. The fishermen from our study confirmed the damage to the nets caused by the crab and pointed out the need to receive guidelines of good practices for the management of this species. The several records reported by fishermen stress the importance of their cooperation as sentinels for the detection of invasive species. In this process, the vo- luntary help offered by citizens in informing scientists about the presence of alien species should not be underestimated. The wide response on social pages dedicated to the knowledge of marine life is proof of this and could constitute in the next future a valid tool to support the monitoring of alien species. ACKNOWLEDGMENTS We are grateful to the referees for valuable suggestions and comments that improved the manuscript, to Frances- co Sciré for technical support, and to: Adolfo Romei who caught and photographed the C. sapidus specimen from Porto Empedocle, Mario Graffeo who caught and filmed the specimen from Sciacca, Marco Schepis who reported and photographed the specimens from southeastern Sicily, to Gaetano Torrisi, Director of the Natural Reser- ves of the Metropolitan City of Catania, who furnished information and pictures about the specimens collected in Simeto Oasis, and to Nicola Parrinello who provided photos of a specimen from Stagnone di Marsala Lagoon. Fig. 3: Specimens of Callinectes sapidus poached within the Oriented Nature Reserve Simeto Oasis in September 2020. Sl. 3: Primerki modre rakovice (Callinectes sapidus), ulovljeni v Naravnem rezervatu Simeto Oasis v sep- tembru 2020. ANNALES · Ser. hist. nat. · 31 · 2021 · 1 6 Luca CASTRIOTA & Manuela FALAUTANO: REVIEWING THE INVASION HISTORY OF THE BLUE CRAB CALLINECTES SAPIDUS (PORTUNIDAE) IN SICILY ..., 1–8 REVIZIJA ZGODOVINE INVAZIJE MODRE RAKOVICE CALLINECTES SAPIDUS (PORTUNIDAE) NA SICILIJI (OSREDNJE SREDOZEMSKO MORJE): PODCENJENA TUJERODNA VRSTA Luca CASTRIOTA & Manuela FALAUTANO ISPRA, Italian Institute for Environmental Protection and Research, Lungomare Cristoforo Colombo n. 4521 (ex complesso Roosevelt), Località Addaura, 90149 Palermo e-mail: luca.castriota@isprambiente.it POVZETEK Tujerodna modra rakovica (Callinectes sapidus), ki izvira iz vzhodne atlantske obale, že dlje časa naseljuje Sredozemsko morje, vključno z italijanskimi morji. Je na seznamu stoterice najbolj nevarnih invazivnih vrst v Sredozemskem morju in domnevajo, da povzroča posledice na biodiverziteti in ribištvu. Do danes je bilo le manjše število primerkov te vrste potrjenih za Sicilijo. V tem zapisu avtorja poročata o statusu modre rakovice v morju okoli Sicilije na podlagi analize potrjenih zapisov iz raznih virov in dodajata nove primere pojavljanja. Analiza kaže, da so bili doslej podatki o razširjenosti te vrste podcenjeni tako glede abundance kot tudi frekvence pojavljanja. Ključne besede: ljubiteljska znanost, tujerodne vrste, Decapoda, Brachyura, vodne poti, lagune ANNALES · Ser. hist. nat. · 31 · 2021 · 1 7 Luca CASTRIOTA & Manuela FALAUTANO: REVIEWING THE INVASION HISTORY OF THE BLUE CRAB CALLINECTES SAPIDUS (PORTUNIDAE) IN SICILY ..., 1–8 REFERENCES Ariani, P.A. & V. Serra (1969): Sulla presenza del Portunus pelagicus (L.) in acque italiane, con os- servazioni sulla morfologia della specie (Crustacea, Decapoda). Arch. Bot. Biogeogr. It., 45, 187-206. Beqiraj, S. & L. Kashta (2010): The establishment of blue crab Callinectes sapidus Rathbun, 1896 in the Lagoon of Patok, Albania (south-east Adriatic Sea). Aquat. Invasions, 5(2), 219-221. Castriota, L., F. 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ANNALES · Ser. hist. nat. · 31 · 2021 · 1 8 Luca CASTRIOTA & Manuela FALAUTANO: REVIEWING THE INVASION HISTORY OF THE BLUE CRAB CALLINECTES SAPIDUS (PORTUNIDAE) IN SICILY ..., 1–8 Van Engel, W.A. (1958): The blue crab and its fishery in the Chesapeake Bay. Part I - Reproduc- tion, early development, growth, and migration. Commer. Fish. Rev., 20, 6−17. Williams, A.B. (1965): Marine decapod crusta- ceans of the Carolinas. Fish. Bull., 65, 1−298. Williams, A.B. (1974): The swimming crabs of the genus Callinectes (Decapoda: Portunidae). Fish. Bull., 72, 685-798. www.oggimilazzo.it (2020): Ritrovato per la prima volta a Milazzo un “Granchio Reale” https:// www.oggimilazzo.it/2020/02/24/ritrovato-per-la- -prima-volta-a-milazzo-un-granchio-reale/ www.tp24.it (2020): Marsala, l’invasione dei granchi blu: una grave minaccia per lo Stagnone. https://www.tp24.it/2020/06/04/cronaca/marsala-l- -invasione-dei-granchi-blu-una-grave-nbsp-mina- ccia-per-lo-stagnone-nbsp/150358 ANNALES · Ser. hist. nat. · 31 · 2021 · 1 9 received: 2021-05-03 DOI 10.19233/ASHN.2021.02 FIRST RECORD OF THE FLAT NEEDLEFISH, ABLENNES HIANS (BELONIDAE) IN CENTRAL MEDITERRANEAN WATERS (WESTERN IONIAN SEA) Alan DEIDUN Department of Geosciences, University of Malta, Msida MSD 2080, Malta Bruno ZAVA Museo Civico di Storia Naturale, via degli Studi 9, 97013 Comiso (RG), Italy Wilderness studi ambientali, via Cruillas 27, 90146 Palermo, Italy Maria CORSINI-FOKA Hellenic Centre for Marine Research, Institute of Oceanography, Hydrobiological Station of Rhodes. Cos Street, 85100 Rhodes, Greece e-mail: mcorsini@hcmr.gr Johann GALDIES Department of Geosciences, University of Malta, Msida MSD 2080, Malta Antonio DI NATALE Aquastudio Research Institute, Via Trapani 6, 98121 Messina, Italy Bruce B. COLLETTE Smithsonian Institution, National Museum of Natural History, Division of Fishes, 10th and Constitution Ave, NW Washington, DC 20560-0159 ABSTRACT Two specimens of Ablennes hians (Valenciennes, 1846) were collected between 2018 and 2020 in nearshore waters off the island of Malta. The first occurrence of the flat needlefish in the central Mediterranean, almost contemporary to its first record in the eastern Levantine Sea, is briefly discussed. Key words: Malta, Ablennes hians, non-indigenous fish, Mediterranean Sea PRIMO RITROVAMENTO DI ABLENNES HIANS (BELONIDAE) IN MEDITERRANEO CENTRALE (MAR IONIO OCCIDENTALE) SINTESI Due esemplari di Ablennes hians (Valenciennes, 1846) sono stati catturati tra il 2018 e il 2020 nelle acque costiere dell’isola di Malta. La prima segnalazione della specie nel Mediterraneo centrale, quasi contemporanea a quella documentata per il Mar di Levante orientale, è brevemente discussa. Parole chiave: Malta, pesci non-indigeni, Mediterraneo ANNALES · Ser. hist. nat. · 31 · 2021 · 1 10 Alan DEIDUN et al.: FIRST RECORD OF THE FLAT NEEDLEFISH, ABLENNES HIANS (BELONIDAE) IN CENTRAL MEDITERRANEAN WATERS (WESTERN IONIAN SEA), 9–16 INTRODUCTION The flat needlefish Ablennes hians (Valenci- ennes, 1846) is one of the 47 species comprised in the ten genera of the family Belonidae (Froese & Pauly, 2021). It has a widespread distribution, being known from tropical and subtropical waters of the eastern and western Atlantic Ocean, as well as from eastern and western Pacific and Indian Oceans, as far as the Red Sea and the Gulf of Aqa- ba (Collette, 1999, 2016; Golani & Fricke, 2018; Golani, 2019; Collette & Bemis, 2019; Alshawy et al., 2019). While the species is not listed among the ichthyofauna of the Gulf of Suez (Golani & Fricke, 2018), it is found among the belonids of the Suez Canal (Sabrah et al., 2018). The flat needlefish is reported in by-catch communities of the pelagic ecosystem in the tropical tuna purse seine fishery of the Eastern Atlantic and Western Indian Oceans (Lezama-Ochoa et al., 2015, 2018). This pelagic fish reaches over 120 cm in standard length, inhabits offshore surface waters, but also coastal waters, is often found near islands, and in estuaries; it occurs both as a solitary and schooling fish; its diet consists mainly of small fishes, such as Atherinidae; the deposited eggs may be found attached to objects in the water using filaments on their surface (Fishelson, 1975; Collette, 1986, 2016; Froese & Pauly, 2021; Golani, 2019). In the Mediterranean, the first specimen of A. hians was collected in September 2018 off the coasts of Israel by trammel net at a depth of 20‒30 m (Go- lani, 2019). A few months later, in February 2019, two specimens were caught off the coasts of Syria in a gill net (Alshawy et al., 2019), and another one, in March 2019, along the coasts of Israel, by purse seine (Tadmor-Levi et al., 2020). These recently documented records of A. hians in the Levantine Sea increase to six the number of belonid species known in the Mediterranean. The five previously known species include the native Belone belone (Linnaeus, 1761), Belone svetovidovi Collette & Parin, 1970, Tylosurus acus acus (Lacépède, 1803), and Tylosurus acus imperialis (Rafinesque, 1810), as well as the rare non-indigenous species of Indo-Pacific origin Tylosurus choram (Rüppell, 1837) (Froese & Pauly, 2021; Galil et al., 2021). Although listed in Zenetos et al. (2010, 2018), the non-indigenous Tylosurus crocodilus (Péron & Le Sueur, 1821) is not included because the single specimen from Hellenic Aegean waters (Sinis, 2005) was probably a misidentified co-generic Mediterranean species. This study documents the first record of A. hians in the coastal waters off the island of Malta and in the central Mediterranean, offering some considera- tions about the possible introduction pathways for this species. MATERIAL AND METHODS On 1 December 2020, one specimen of A. hians (specimen a) was caught off the southern coast of the island of Malta (35.808434°N, 14.537536°E), by means of a kayak fishing rod, at a depth of 10 m, over a rocky seabed. The bait was sliced fragments of Arenicola sp. (Polychaeta). The fisher reported the capture through social media (Spot the Alien Fish campaign Facebook page, https://www.facebook. com/aliensmalta). The Spot the Alien Fish citizen science campaign was launched by the University of Malta in 2017 to collate a national database of all records made by different sea users in relation to non-indigenous species (NIS) of fish within Maltese waters. Reports to the campaign can be submitted through a dedicated web portal (https://www.um.edu. mt/newspoint/news/2020/06/spot-alien-website- launched), as well as through the corresponding campaign social media page and email address. Upon capture, the fisher noted unusual evident black bars/markings in the posterior part of the fish, which led him to promptly sketch and submit a drawing of the same markings (Fig. 1A) to the citizen science campaign’s social media platform. Specimen a was not preserved by the fisher, who did, however, take photographs (Fig. 1B, C). Its length was meas- ured using a plastic bottle; the bottle having a known length of 20.5 cm, it was placed alongside the fish and included in the original photograph. In Fig. 1C, the bar corresponds to the length of the bottle. Two months after the submission of the above A. hians photo to social media, the fishery community of the island was alerted about it by one of the authors (AD) and the photo of another specimen (specimen b) emerged on the mentioned platform (Fig. 2). Specimen b had been caught two years earlier, on 22 September 2018, in a location off the south-eastern coast of the island of Malta (35.819001°N, 14.559989°E), using a rod fishing technique known as ‘spinning’ from land. This sam- ple was not preserved by the recreational fisher, so the only morphometric attribute that could be inferred from the corresponding photo was the total length. RESULTS Both specimens of A. hians (specimen a: 61.5 cm total length, 57.5 cm standard length, 330 g ap- proximate weight; specimen b: 75.0 cm estimated total length) were identified based on the submitted photographs and drawing/sketch, following the de- scriptions by Collette & Parin (1970), Collette (1999, 2016), Collette & Bemis (2019), Golani (2019), and Alshawy et al. (2019). Body elongate and laterally compressed. Upper and lower jaws greatly elon- ANNALES · Ser. hist. nat. · 31 · 2021 · 1 11 Alan DEIDUN et al.: FIRST RECORD OF THE FLAT NEEDLEFISH, ABLENNES HIANS (BELONIDAE) IN CENTRAL MEDITERRANEAN WATERS (WESTERN IONIAN SEA), 9–16 Fig. 1: Ablennes hians (specimen a) caught in December 2020 off Malta (A, drawing made on board; B, immediately upon landing; C, a few minutes after landing, white bar 20.5 cm, details in Material and Methods (Drawing and photographs by L. Saliba). Sl. 1: Ablennes hians (primerek a), ujet decembra 2020 pri Malti (A, risba na tablici; B, ravnokar ujet; C, nekaj minut po ulovu, bela črta 20,5 cm, detajli v poglavju Materiali in metode (Slika in fotografije: L. Saliba). ANNALES · Ser. hist. nat. · 31 · 2021 · 1 12 Alan DEIDUN et al.: FIRST RECORD OF THE FLAT NEEDLEFISH, ABLENNES HIANS (BELONIDAE) IN CENTRAL MEDITERRANEAN WATERS (WESTERN IONIAN SEA), 9–16 gate, with small sharp teeth. Apparently, there were no lateral keels on the caudal peduncle. Dorsal and anal fins opposite, their anterior parts presenting moderately falcate lobes; caudal fin deeply forked, lower lobe longer than upper. Colour: bluish-green back, light blue flanks, white ventral surface; pelvic fins whitish, other fins appearing darker, posterior lobe of dorsal fin black (Fig. 2); a series of at least 13 dark vertical bars on the body along the sides (Figs. 1B-C, 2). In Fig. 1C, the vertical bars appear slightly faded compared to Fig. 1B, probably due to different light exposure values of the two photo- graphs. Jaws pinkish. DISCUSSION The presumed arrival in 2020 of A. hians in Mal- tese waters led us initially to hypothesise a rapid spread of this newly introduced fish from the Levan- tine basin (Golani, 2019; Alshawy et al., 2019) to the central Mediterranean, as it was reminiscent of the exceptional spread rate of Fistularia commersonii Rüppell, 1838 within the Mediterranean observed two decades ago. In fact, in only two years since its first record in the basin in 2000, off the Mediterra- nean coasts of Israel (Golani, 2000), that Lessepsian migrant extended its distribution range by over 2500 km, as far as the Italian island of Lampedusa in the central parts of the basin (Azzurro et al., 2004), earning the species the title of ‘Lessepsian sprinter’ (Karachle et al., 2004). Golani (2019) underlined the uncertainty of the origin of the first A. hians specimen found in Israel, but since the Suez Canal was included in the distribution range of the flat needlefish (Sabrah et al., 2018), a tentative intro- duction into the Mediterranean via the Suez Canal (Lessepsian migration) was initially hypothesised, and this main route of introduction was also as- cribed to the A. hians specimens from Syrian waters (Alshawy et al., 2019). However, recent molecular analysis of A. hians samples collected from a broad geographical range revealed that within A. hians, previously considered a single circumtropical spe- cies, there may be several cryptic taxa (Tadmor-Levi et al., 2020). Given the genetic differences between Red Sea specimens and the specimen sampled from Israel (Mediterranean Sea), the Lessepsian migra- tion theory for the introduction of A. hians into the Mediterranean appears less probable, albeit not impossible; further studies are required to verify the introduction pathway for the species into the basin (Tadmor-Levi et al., 2020). The unexpected emergence of an even earlier record of A. hians (dating back to September 2018) from Maltese waters and the subsequent finding of the same species in 2020 within the same waters may further substantiate the hypothesised improb- ability of the arrival of the species in the Mediter- ranean through Lessepsian migration, in agreement with Tadmor-Levi et al. (2020). The outcomes of our study, in fact, suggest that a different route of intro- duction of the species into the Mediterranean should be considered. The Strait of Sicily, east of which the Malta archipelago is located, is an ecological corridor for the east-west and west-east dispersion of exotic species within the Mediterranean basin, Fig. 2: Ablennes hians (specimen b) caught off Malta in September 2018 (Photograph by M. Caruana, sub- mitted to social media in February 2021). Sl. 2: Ablennes hians (primerek b) ujet pri Malti septembra 2018 (Fotografija: M. Caruana, objavljen v socialnih medijih februarja 2021). ANNALES · Ser. hist. nat. · 31 · 2021 · 1 13 Alan DEIDUN et al.: FIRST RECORD OF THE FLAT NEEDLEFISH, ABLENNES HIANS (BELONIDAE) IN CENTRAL MEDITERRANEAN WATERS (WESTERN IONIAN SEA), 9–16 i.e., a biogeographical crossroads between the two parts of the basin (Guidetti et al., 2010; Azzurro et al., 2014; Insacco & Zava, 2017; Deidun et al., 2021). As a result, an Atlantic origin of A. hians inhabiting the Mediterranean cannot be completely discounted. Although Moroccan Atlantic waters are not included in the Atlantic distribution range of the flat needlefish by Collette & Bemis (2019), the lat- ter is listed as an unexploited species of Morocco that could acquire economic and commercial value (Menioui, 2009). Given the pelagic character of A. hians, a passive (not mediated by human agency) range expansion from the tropical east Atlantic into the Mediterranean via the Strait of Gibraltar could be speculated, analogously to an increasing number of non-native species within the basin (Essl et al., 2019). This hypothesis, however, is not supported by any records of the species from the western basin of the Mediterranean, which is anomalous for a puta- tive range-expanding species of Atlantic origin. Given that the Sicily Channel is a busy ship- ping lane, alternative vectors linked with maritime transport, including vessel ballast water and oil platforms, could also be responsible for introduc- ing the species into the central Mediterranean, as has been documented in previous studies (e.g., Pajuelo et al., 2016; Insacco & Zava, 2017). Based on the records of A. hians from a wide geographi- cal range within the basin, multiple instances of introduction of the species into the same basin are plausible; however, as suggested by Tadmor-Levi et al. (2020); a larger sample size is necessary in any future genetic investigation in order to ascertain the origin of the flat needlefish in the Mediterranean. ACKNOWLEDGEMENTS The authors warmly thank the fishers Laurence Saliba and Miguel Caruana for providing information on the capture of the fishes studied in the present work and photographic material. The authors are also indebted to the International Ocean Institute (IOI) for financially supporting the University of Malta in conducting the Spot the Alien Fish citizen science campaign. ANNALES · Ser. hist. nat. · 31 · 2021 · 1 14 Alan DEIDUN et al.: FIRST RECORD OF THE FLAT NEEDLEFISH, ABLENNES HIANS (BELONIDAE) IN CENTRAL MEDITERRANEAN WATERS (WESTERN IONIAN SEA), 9–16 PRVI ZAPIS O POJAVLJANJU PLOŠČATE MORSKE IGLE, ABLENNES HIANS (BELONIDAE) V VODAH OSREDNJEGA SREDOZEMSKEGA MORJA (ZAHODNO JONSKO MORJE) Alan DEIDUN Department of Geosciences, University of Malta, Msida MSD 2080, Malta Bruno ZAVA Museo Civico di Storia Naturale, via degli Studi 9, 97013 Comiso (RG), Italy Wilderness studi ambientali, via Cruillas 27, 90146 Palermo, Italy Maria CORSINI-FOKA Hellenic Centre for Marine Research, Institute of Oceanography, Hydrobiological Station of Rhodes. Cos Street, 85100 Rhodes, Greece e-mail: mcorsini@hcmr.gr Johann GALDIES Department of Geosciences, University of Malta, Msida MSD 2080, Malta Antonio DI NATALE Aquastudio Research Institute, Via Trapani 6, 98121 Messina, Italy. Bruce B. COLLETTE Smithsonian Institution, National Museum of Natural History, Division of Fishes, 10th and Constitution Ave, NW Washington, DC 20560-0159 POVZETEK Dva primerka ploščate morske igle, Ablennes hians (Valenciennes, 1846), sta bila ujeta med 2018 in 2020 v obalnih vodah Malte. Avtorji razpravljajo o prvem pojavljanju ploščate morske igle v osrednjem Sredozemskem morju, ki časovno sovpada s prvim zapisom o pojavljanju te vrste v vzhodnem Levantskem morju. Ključne besede: Malta, Ablennes hians, tujerodna vrsta, Sredozemsko morje ANNALES · Ser. hist. nat. · 31 · 2021 · 1 15 Alan DEIDUN et al.: FIRST RECORD OF THE FLAT NEEDLEFISH, ABLENNES HIANS (BELONIDAE) IN CENTRAL MEDITERRANEAN WATERS (WESTERN IONIAN SEA), 9–16 REFERENCES Alshawy, F., A. 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Zenetos, A., M. Corsini-Foka, F. Crocetta, V. Gerova- sileiou, P.K. Karachle, N. Simboura, K. Tsiamis & M.-A. Pancucci-Papadopoulou (2018): Deep cleaning of alien species records in the Greek Seas (2018 update). Manag. Biol. Invasions, 9(3), 209-226. Doi: 10.3391/ mbi.2018.9.3.04. ANNALES · Ser. hist. nat. · 31 · 2021 · 1 17 received: 2021-05-03 DOI 10.19233/ASHN.2021.03 OCCURRENCE OF RETICULATED LEATHERJACKET STEPHANOLEPIS DIASPROS (MONACANTHIDAE) IN THE CENTRAL MEDITERRANEAN SEA, AND A NEW RECORD FROM THE TUNISIAN COAST Mohamed Mourad BEN AMOR, Khadija OUNIFI-BEN AMOR & Marouène BDIOUI Institut National des Sciences et Technologies de la Mer, port de pêche, 2025 La Goulette, Tunisia Christian CAPAPÉ Laboratoire d’Ichtyologie, Université de Montpellier, case 104, 34095 Montpellier cedex 5, France e-mail: capape@univ-montp2.fr ABSTRACT The authors describe and comment the capture of a specimen of reticulated leatherjacket Stephanolepis diaspros Fraser-Brünner, 1940. This is the first capture for this species made in the Gulf of Hammamet in eastern Tunisia. Such a record also fills the gap in the distribution of the species in Tunisian waters, which could be considered as the core of the species in the central Mediterranean Sea and perhaps in the entire Mediterranean. Key words: Stephanolepis diaspros, extension range, Gulf of Hammamet, eastern Tunisia PRESENZA DI MONACANTO RETICOLATO STEPHANOLEPIS DIASPROS (MONACANTHIDAE) NEL MEDITERRANEO CENTRALE E NUOVA CATTURA IN TUNISIA SINTESI Gli autori descrivono e commentano la cattura di un esemplare di monacanto reticolato Stephanolepis diaspros Fraser-Brünner, 1940. L’evento rappresenta la prima cattura della specie nel Golfo di Hammamet, nella Tunisia orientale. Il ritrovamento aiuta a riempire le lacune inerenti la distribuzione della specie nelle acque tunisine, che potrebbero venir considerate come il centro della presenza della specie nel Mediterraneo centrale e forse in tutto il Mediterraneo. Parole chiave: Stephanolepis diaspros, range di estensione, Golfo di Hammamet, Tunisia orientale ANNALES · Ser. hist. nat. · 31 · 2021 · 1 18 Mohamed Mourad BEN AMOR et al.: OCCURRENCE OF RETICULATED LEATHERJACKET STEPHANOLEPIS DIASPROS (MONACANTHIDAE) IN THE CENTRAL ..., 17–22 INTRODUCTION Since its first record from the Levant Basin (Steinitz, 1927), the Lessepsian migrant reticulated leatherjacket Stephanolepis diaspros Fraser-Brünner, 1940 has pro- gressively migrated toward western areas (Golani, 1998). Viable populations are successfully established in the central Mediterranean Sea (Tortonese, 1986) and in Turkish waters (Taskavak & Bilecenoglu, 2001). In the former area, S. diaspros found favourable environmental parameters for reproduction and de- velopment, especially in Tunisian waters, for example, in the Gulf of Gabès in the south (Zouari-Ktari et al., 2008; Zouari-Ktari & Bradaï, 2011), and northwards, off Bizerte and in the Lagoon of Bizerte (Bdioui et al., 2004; Shaiek et al., 2019). Additionally, the northern- most extension range of the species reached the area off Tabarka, close to the Algerian border (Ben Amor & Capapé, 2008). Recent investigations conducted off the eastern Tunisian coast, mainly in the Gulf of Hammamet, sup- ported by the assistance of fishermen aware of fishing grounds, allowed the collection of the specimen of S. diaspros described in the present paper. MATERIAL AND METHODS The specimen was caught by trawl with 40 mm stretched mesh size on 30 January 2021, in the Bay of Monastir, the Gulf of Hammamet, eastern Tunisia (35°46’36.94” N and 10°51’12.75” E; Fig. 1). The capture occurred at a depth between 30 and 35 m, on sandy-muddy bottom partially covered by seagrass and algae. The S. diaspros was caught together with cepha- lopod species, such as the common octopus Octopus vulgaris Cuvier, 1797, and teleost species, including the European seabass Dicentrarchus labrax (Linnaeus, 1758), the red mullet Mullus barbatus Linnaeus, 1758, the salema Sarpa salpa (Linnaeus, 1758), and the red scorpionfish Scorpaena scrofa Linnaeus, 1758. Abun- dant samples of ocean grass-wrack Posidonia oceanica (L.) Delille, 1813 were also collected during the trawls carried out in the Gulf of Hammamet. The recorded morphometric measurements, length measured to the nearest millimetre following Ben Amor & Capapé (2008), weight to the nearest gram, and meristic counts are summarised in Table 1. The specimen was fixed in 10% buffered formalin, preserved in 75% ethanol, and deposited in the Ichthyological Collection of the Institut National des Sciences et Techniques de la Mer of Tunis (Tunisia) under catalogue number INSTM-Ste- dia 01. RESULTS AND DISCUSSION The studied specimen was identified as Stepha- nolepis diaspros following previous descriptions by Tortonese (1967, 1986), Golani et al. (2017), Dulčić & Pallaoro (2003), Bdioui et al. (2004), and Shaiek et al. (2019). It displayed a brown-to-grey colour, with dark posterior areas and sinuous grey lines on the sides, while dark bands in the caudal fin were not visible (Fig. 2). Fig. 1: Capture sites of Stephanolepis diaspros in the central Mediterranean Sea. 1. Gulf of Gabès (Chakro- un, 1966). 2. Lagoon of Bizerte (Bdioui et al., 2004). 3. Off Tabarka (Ben Amor & Capapé, 2008). 4. Off Bizer- te (Shaiek et al., 2019). 5. Lagoon of Bizerte (Shaiek et al., 2019). 6. Bay of Monastir, Gulf of Hammamet (this study). The black star and black circle indicate the captures of the species in waters surrounding the Island of Lampedusa and the Island of Malta, respecti- vely (Deidun et al., 2015). Sl. 1: Zemljevid lokalitet, kjer so bili ujeti primerki vrste Stephanolepis diaspros v osrednjem Sredozemskem morju. 1. Zaliv Gabès (Chakroun, 1966). 2. Laguna v Bizerti (Bdioui et al., 2004). 3. Tabarka (Ben Amor & Capapé, 2008). 4. Bizerta (Shaiek et al., 2019). 5. La- guna v Bizertie (Shaiek et al., 2019). 6. Zaliv Monastir v zalivu Hammamet (ta raziskava). Črna zvezdica in črni krog kažeta lokaliteti, kjer so bili ujeti primerki v okolici Lampeduse in Malte (Deidun et al., 2015). ANNALES · Ser. hist. nat. · 31 · 2021 · 1 19 Mohamed Mourad BEN AMOR et al.: OCCURRENCE OF RETICULATED LEATHERJACKET STEPHANOLEPIS DIASPROS (MONACANTHIDAE) IN THE CENTRAL ..., 17–22 Tab. 1: Comparison of morphometric measurements, meristic counts, and total body weight recorded in the spe- cimens of Stephanolepis diaspros, collected in the Bay of Monastir, Gulf of Hammamet (ref. INSTM-Ste-dia-01), northern Tunisian coast (FST-STE-diasp1), and the Lagoon of Bizerte (ISPAB-Ste-dia-01). Tab. 1: Primerjava morfometričnih meritev, merističnega štetja in skupne telesne mase, zabeleženih pri osebkih Stephanolepis diaspros, ujetih v Monastirju v zalivu Hammamet (ref. INSTM-Ste-dia-01), ob severni tunizijski obali (FST-STE-diasp1) in v Laguni Bizerte (ISPAB-Ste-dia-01). References INSTM-Ste-dia 01 FST-STE-diasp1 FSB-Ste-dia-01 Measurements mm %TL mm %TL mm %TL Total length (TL) 125 100.0 154 100 215 100 Standard length (SL) 104 83.2 125 81.2 185 86.05 Head length 27 21.6 34 22.1 55 25.6 First predorsal length 32 25.9 41.1 26.6 49 22.6 Second predorsal length 58 46.2 72.4 47.01 95 43.9 Preanal length 59 47.5 74.3 48.2 97 45.4 Prepectoral length 34 27.1 42.9 27.8 49 23.0 First dorsal fin length 6 4.9 7.6 4.9 13 6.3 Second dorsal fin length 41 32.9 51.8 33.6 73 34.2 Anal fin length 37 29.8 47.2 30.6 66 30.6 Pectoral fin length 10 8.5 14.3 9.2 9 11.6 Caudal fin length 22 17.9 28.8 18.7 25 25.8 Maximal body length 48 38.4 60.3 39.1 86 39.8 Minimal body length 9 7.2 12.4 8.1 - - Eye diameter 5 4.2 6.8 4.4 11 5.3 Interorbital length 8 6.7 11.6 7.5 12 5.8 Preorbital length 16 13.0 21.3 13.8 36 16.6 Postorbital length 5 4.1 6.8 4.4 6 2.9 Meristic counts First dorsal fin rays I I I Second dorsal fin rays 33 33 31 Anal fin rays 31 31 31 Pectoral fin rays 13 13 13 Caudal fin rays I+10+I I+10+I I+10+I Total weight (gram) 71 61 196 ANNALES · Ser. hist. nat. · 31 · 2021 · 1 20 Mohamed Mourad BEN AMOR et al.: OCCURRENCE OF RETICULATED LEATHERJACKET STEPHANOLEPIS DIASPROS (MONACANTHIDAE) IN THE CENTRAL ..., 17–22 The capture of the specimen more probably oc- curred during its migration from the southern area, where the species lives freely in the wild, than from the northern area, where an established population can also be found, inhabiting the Lagoon of Bizerte (Shaiek et al., 2019), a restricted area communicat- ing with the open sea by a narrow navigation canal (Harzallah, 2003; Ounifi-Ben Amor et al., 2016). Ap- parently, the specimen was captured together with large S. salpa, probably adults, which are considered almost exclusively herbivorous (Bauchot & Hureau, 1986). S. diaspros feeds on a large variety of benthic invertebrates, and sometimes on algae and plants (Zouari-Ktari et al., 2008). Therefore, competition pressure between herbivorous fish species and S. diaspros remains generally limited, since the latter also find available food in the seagrass meadows they inhabit (El-Ganainy & Sabra, 2008). At present, S. diaspros is known throughout the Tunisian coast, although the capture of a single spec- imen in the Gulf of Hammamet does not constitute sufficient evidence to draw any conclusions about the real status of the species in this area. Further records are needed to confirm the hypothesis of a successful establishment of a S. diaspros population in this eastern Tunisian region. However, the present record fills a gap in the distribution of the species along the Tunisian coast. Conversely, it appears that S. diaspros is successfully established in two areas; the Gulf of Gabès and the Lagoon of Bizerte. Morphometric measurements and meristic counts recorded in specimens from these areas are practi- cally identical (see Tab. 1), suggesting that the same population may be inhabiting the two separate areas. However, the plausibility of such a hypothesis would have to be verified by means of molecular tools and genetic analysis. S. diaspros remains abundant in Tunisian waters, to the point that this region could at present be considered the core area of the species in the central Mediterranean Sea, and probably in the wider Mediterranean as well. Fig. 2: Specimen of Stephanolepis diaspros collected in the Bay of Monastir, Gulf of Hammamet (ref. INSTM- -Ste-dia-01), scale bar = 30 mm. Sl. 2: Primerek vrste Stephanolepis diaspros, ujet v Monastirju v zalivu Hammamet (ref. INSTM-Ste- -dia-01), merilo = 30 mm. ANNALES · Ser. hist. nat. · 31 · 2021 · 1 21 Mohamed Mourad BEN AMOR et al.: OCCURRENCE OF RETICULATED LEATHERJACKET STEPHANOLEPIS DIASPROS (MONACANTHIDAE) IN THE CENTRAL ..., 17–22 POJAVLJANJE AFRIŠKEGA KOSTOROGA, STEPHANOLEPIS DIASPROS (MONACANTHIDAE), V OSREDNJEM SREDOZEMSKEM MORJU IN PRVI PODATEK ZA TUNIZIJSKO OBALO Mohamed Mourad BEN AMOR, Khadija OUNIFI-BEN AMOR & Marouène BDIOUI Institut National des Sciences et Technologies de la Mer, port de pêche, 2025 La Goulette, Tunisia Christian CAPAPÉ Laboratoire d’Ichtyologie, Université de Montpellier, case 104, 34095 Montpellier cedex 5, France e-mail: capape@univ-montp2.fr POVZETEK Avtorji poročajo in razpravljajo o najdbi primerka afriškega kostoroga, Stephanolepis diaspros Fraser-Brünner, 1940. Ta je bil prvič najden v zalivu Hammamet v vzhodni Tuniziji. Ta primer je zapolnil vrzel v razširjenosti te vrste vzdolž tunizijske obale in predstavlja pomembno območje te vrste v osrednjem Sredozemskem morju in morda v celotnem bazenu. 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ANNALES · Ser. hist. nat. · 31 · 2021 · 1 23 received: 2021-04-16 DOI 10.19233/ASHN.2021.04 NEW RECORD OF EPINEPHELUS AREOLATUS IN THE MEDITERRANEAN SEA: FIRST RECORD FROM SYRIA Sara AL MABRUK Department of General Nursing Technology, Higher Institute of Science and Technology, Cyrene, Libya Marine Biology in Libya Society, El Bayda, Libya e-mail: sara.almabruk@omu.edu.ly Ioannis GIOVOS Sea, Environmental Organization for the Preservation of the Aquatic Ecosystems, Thessaloniki, Greece e-mail: ioannis.giovos@isea.com.gr Francesco TIRALONGO Department of Biological, Geological and Environmental Sciences, University of Catania, Italy Ente Fauna Marina Mediterranea, Avola, Italy e-mail: francesco.tiralongo@unict.it ABSTRACT One specimen of the Areolate Grouper Epinephelus areolatus (Forsskål, 1775) was caught on 29th May 2019 off the coast of Latakia. This represents the first record of the species for the Syrian waters and the fourth for the Mediterranean Sea. We finally discuss its introduction pathway in the Mediterranean. Key words: Serranidae, eastern Mediterranean, non-indigenous fish, citizen science NUOVA SEGNALAZIONE DI EPINEPHELUS AREOLATUS NEL MAR MEDITERRANEO: PRIMA SEGNALAZIONE DALLA SIRIA SINTESI Un esemplare di Epinephelus areolatus (Forsskål, 1775) è stato catturato il 29 maggio 2019 al largo della costa di Latakia. Questa cattura rappresenta la prima segnalazione della specie da acque siriane e la quarta segnalazione per il mare Mediterraneo. Si discute la via di introduzione di questa specie in Mediterraneo. Parole chiave: Serranidae, Mediterraneo orientale, pesci non indigeni, scienza del cittadino ANNALES · Ser. hist. nat. · 31 · 2021 · 1 24 Sara AL MABRUK et al.: NEW RECORD OF EPINEPHELUS AREOLATUS IN THE MEDITERRANEAN SEA: FIRST RECORD FROM SYRIA, 23–28 INTRODUCTION The Mediterranean Sea hosts six non-indige- nous Epinephelus Bloch, 1793 species, namely Epinephelus areolatus (Forsskål, 1775), Epinephe- lus coioides (Hamilton, 1822), Epinephelus fasciatus (Forsskål, 1775), Epinephelus geoffroyi (Klunzinger, 1870), Epinephelus malabaricus (Bloch & Schneider, 1801) and Epinephelus merra Bloch, 1793 (Golani et al., 2002, 2015). Among them, E. areolatus, commonly known as the Areolate Grouper, is a species of Indo-Pacific origin, whose distribution extends from the Red Sea and eastern coast of Africa to southern Japan and New Caledonia (Froese & Pauly, 2021). In its native range, E. areolatus is common in coastal waters, on seagrass beds and on soft bottoms close to hard substrates, such as rocky reefs or dead corals, where it feeds on fish and benthic inverte- brates (Heemstra & Randall 1993; Randall et al., 1998). This species was first recorded from the Mediterranean Sea based on a specimen caught along the Israeli coast in 2015 (Rothman et al., 2016). More recently, two further specimens were collected in Lebanon in 2019 (Bariche & Edde, 2020). We hereby report for the first time the presence of E. areolatus in Syrian waters, discussing the introduction pathway of this recently introduced non-indigenous fish in the Mediterranean Sea. MATERIAL AND METHODS On 11th May 2020, a Syrian professional fisher- man posted a photo of a fish unknown to him on the Facebook®group “ديص نمدم” (fishing addict), asking for an identification. The particular color pattern of the grouper, represented by a reticulated pattern of yellow-brownish spots scattered over body (Heem- stra & Randall, 1993; Craig et al., 2012), easily allowed the authors of the present note to identify it as E. areolatus. Soon after, we contacted the fish- erman asking for further data about the catch. In particular, the fish was caught on 29th May 2019 Fig. 1: Location in which the specimen of Epinephelus areolatus was caught on 29 May 2019, at Lattakia, Syria, eastern Mediterranean Sea. Sl. 1: Zemljevid obravnavanega območja z označeno lokaliteto, kjer je bil 29. maja 2019 pri Latakiji (Sirija, vzho- dno Sredozemsko morje) ujet primerek rdečepikaste kirnje. ANNALES · Ser. hist. nat. · 31 · 2021 · 1 25 Sara AL MABRUK et al.: NEW RECORD OF EPINEPHELUS AREOLATUS IN THE MEDITERRANEAN SEA: FIRST RECORD FROM SYRIA, 23–28 with a trolling line operating at a depth of 61 m, off the coast of Latakia, northern Syria (35°32’27.6”N 35°45’04.2”E) (Fig. 1). Unfortunately, the speci- men (Fig. 2) was consumed by the fisherman and therefore it was not possible to carry out further analysis. However, measurements of the fish’s size were carried out analyzing the photo provided by the fisherman using the ImageJ software (Schneider et al., 2012): the length of the fish was estimated using as standard the size of the thumbnail of the fisherman (Scannella et al., 2020). Moreover, using the coefficients of the total length-weight relation- ship, it was possible to estimate the weight of the fish (Froese & Pauly, 2021). RESULTS AND DISCUSSION The fish had an estimated total length (TL) of 37 cm, a standard length (SL) of 30.5 cm, and a weight of 702 g. It represents the fourth specimen of E. areolatus reported from the Mediterranean Sea and the first known from Syria. Epinephelus areolatus was commonly reported as a Lessepsian immigrant (Rothman et al., 2016; Bariche & Edde, 2020). Indeed, considering that past records occurred near the Suez Canal, and the fact that the species naturally occurs in the Red Sea, the introduction through this pathway is the most probable explanation for its presence in the basin. Concerning our record from Syrian waters, we also suggest the Suez Canal as introduction pathway for the Mediterranean Sea, or a secondary introduc- tion from an established Mediterranean population (Coll et al., 2010). This Lessepsian immigrant appears to spread quite rapidly through the Mediterranean Sea, and although to date only four specimens were recorded, we can’t rule out the presence of an established population in the eastern part of the basin. Further studies are therefore necessary to better understand the expansion dynamics of this species, whose abundance is still probably low. In this regard, social media and citizen science play an important role in the monitoring and early detection of non-indigenous species (Azzurro et al., 2013; Bariche & Azzurro, 2016; Giovos et al., 2019; Tiralongo et al., 2019, 2020; Azzurro & Tiralongo, 2020; Al Mabruk et al., 2021). In conclusion, the increasing number of alien fish, and in general of alien species, in the Mediterranean Sea, and in particular in its eastern part, highlights a dramatic ecosystem change due to alteration of its biodiversity. The Mediterranean Sea is the most globally impacted ecoregion by bioinvasions (Katsanevakis et al., 2014). To date, more than 100 alien fish species have been recorded in the Mediterranean Sea (Galil & Goren, 2014), and their introduction rate seems to increase continuously, primarily due to the opening of the Suez Canal (Katsanevakis et al., 2014). Monitoring programs, with the help of citizen scientists, appear to be an excellent low-cost support in order to study the biological invasions dynamics in the basin and to upgrade the checklist in neglected country such as Syria (Ali, 2018; Al Mabruk et al., 2021). Fig. 2: Epinephelus areolatus, specimen caught on 29 May 2019 with a trolling line operating at a depth of 61 m at Lattakia, Syria (photo by Nizar Aziz). Sl. 2: Primerek rdečepikaste kirnje (Epinephelus areolatus), ujet na parangal 29. maja 2019 na globini 61 m pri Latakiji (Sirija, vzhodno Sredozemsko morje) (foto: Nizar Aziz). ANNALES · Ser. hist. nat. · 31 · 2021 · 1 26 Sara AL MABRUK et al.: NEW RECORD OF EPINEPHELUS AREOLATUS IN THE MEDITERRANEAN SEA: FIRST RECORD FROM SYRIA, 23–28 ACKNOWLEDGMENTS The authors would like to warmly thank the professional fisherman Nizar Aziz for sharing the information and photos with us and to col- leagues Bruno Zava and Dr. Danilo Scannella, National Research Council, Institute for Bio- logical Resources and Marine Biotechnologies, CNR-IRBIM, Mazara del Vallo Italy for the valu- able help. ANNALES · Ser. hist. nat. · 31 · 2021 · 1 27 Sara AL MABRUK et al.: NEW RECORD OF EPINEPHELUS AREOLATUS IN THE MEDITERRANEAN SEA: FIRST RECORD FROM SYRIA, 23–28 NOVI ZAPIS O POJAVLJANJU RDEČEPIKASTE KIRNJE (EPINEPHELUS AREOLATUS) V SREDOZEMSKEM MORJU: PRVI PODATKI ZA SIRIJO Sara AL MABRUK Department of General Nursing Technology, Higher Institute of Science and Technology, Cyrene, Libya Marine Biology in Libya Society, El Bayda, Libya e-mail: sara.almabruk@omu.edu.ly Ioannis GIOVOS Sea, Environmental Organization for the Preservation of the Aquatic Ecosystems, Thessaloniki, Greece e-mail: ioannis.giovos@isea.com.gr Francesco TIRALONGO Department of Biological, Geological and Environmental Sciences, University of Catania, Italy Ente Fauna Marina Mediterranea, Avola, Italy e-mail: francesco.tiralongo@unict.it POVZETEK Primerek rdečepikaste kirnje (Epinephelus areolatus (Forsskål, 1775)) je bil ujet 29. maja 2019 ob obali Latakije. Gre za prvi zapis o pojavljanju te vrste za sirske vode in četrti za Sredozemsko morje. Avtorji razpravljajo o načinu prihoda vrste v Sredozemsko morje. Ključne besede: Serranidae, vzhodno Sredozemsko morje, tujerodne ribe, ljubiteljska znanost Località Taxa totali Località Taxa totali Bartolići 13 Marinci 15 Barušići 15 Penićiće 5 Bračana 7 Podkuk 1 Butoniga 10 Prodani 11 Buzet 30 Roč 4 Črnica 1 Ročko polje 6 Erkovčići 6 Sv. Donat 26 Gornja Nugla 7 Svi Sveti 15 Hum 21 Škuljari 1 Klarići 1 Štrped 1 Krti 29 Veli Mlun 7 Krušvari 14 Vrh 14 Mandalenići 4 Žonti 7 ANNALES · Ser. hist. nat. · 31 · 2021 · 1 28 Sara AL MABRUK et al.: NEW RECORD OF EPINEPHELUS AREOLATUS IN THE MEDITERRANEAN SEA: FIRST RECORD FROM SYRIA, 23–28 REFERENCES Al Mabruk, S.A.A., A. Abdulghani, O.M. Nour, M. Adel, F. Crocetta, N. Doumpas, P. Kleitou & F. Tiralon- go (2021): The role of social media in compensating for the lack of field studies: Five new fish species for Mediterranean Egypt. J. 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ANNALES · Ser. hist. nat. · 30 · 2020 · 1 29 Claudio BATTELLI & Neža GREGORIČ: FIRST REPORT OF AN AEGAGROPILOUS FORM OF RYTIPHLAEA TINCTORIA FROM THE LAGOON OF STRUNJAN ..., 61–68 SREDOZEMSKI MORSKI PSI SQUALI MEDITERRANEI MEDITERRANEAN SHARKS ANNALES · Ser. hist. nat. · 30 · 2020 · 1 30 Claudio BATTELLI & Neža GREGORIČ: FIRST REPORT OF AN AEGAGROPILOUS FORM OF RYTIPHLAEA TINCTORIA FROM THE LAGOON OF STRUNJAN ..., 61–68 ANNALES · Ser. hist. nat. · 31 · 2021 · 1 31 received: 2020-12-24 DOI 10.19233/ASHN.2021.05 NOTES ON A RARE CASE OF BLUNTNOSE SIXGILL SHARK HEXANCHUS GRISEUS STRANDED ON THE COAST OF TUSCANY IN THE CENTRAL TYRRHENIAN SEA Primo MICARELLI & Francesca Romana REINERO Centro Studi Squali – Istituto scientifico Loc. Valpiana Massa Marittima (GR), Italy e-mail: direzione@centrostudisquali.org Emilio SPERONE Dipartimento di Biologia, Ecologia e Scienze della Terra. Università della Calabria (CS), Italy ABSTRACT A rare stranding event involving a 297 cm long mature male bluntnose sixgill shark (Hexanchus griseus) occurred on the Tuscan coast in the central Tyrrhenian Sea. The stranded specimen had 6 rows of teeth indicating that it belonged to the H. griseus and not to the Hexanchus nakamurai species, which only has 5. Biometric data on two teeth of the left front region of the lower jaw were collected. The body of the specimen did not show evidence of capture, only a deep cut at the height of the orbital arch suggesting a crash or the ramming of a boat. Key words: bluntnose sixgill shark, Hexanchus griseus, shark stranding, teeth, Mediterranean Sea NOTE SU UN RARO CASO DI SPIAGGIAMENTO DI CAPOPIATTO HEXANCHUS GRISEUS LUNGO LA COSTA TOSCANA NEL MAR TIRRENO CENTRALE SINTESI Un raro evento di spiaggiamento che ha coinvolto un capopiatto maschio maturo lungo 297 cm (Hexanchus griseus) si è verificato lungo la costa toscana nel mar Tirreno centrale. L’esemplare spiaggiato presentava 6 file di denti che indicavano l’appartenenza alla specie H. griseus e non alla specie Hexanchus nakamurai, che ne ha solo 5. Sono stati raccolti dati biometrici su due denti della regione anteriore sinistra della mascella inferiore. Il corpo dell’esemplare non mostrava segni di cattura, solo un profondo taglio all’altezza dell’arco orbitale che suggeriva una collisione o lo speronamento di una barca. Parole chiave: capopiatto, Hexanchus griseus, spiaggiamento di squalo, denti, Mediterraneo ANNALES · Ser. hist. nat. · 31 · 2021 · 1 32 Primo MICARELLI et al.: NOTES ON A RARE CASE OF BLUNTNOSE SIXGILL SHARK HEXANCHUS GRISEUS STRANDED ON THE COAST OF TUSCANY ..., 31–36 INTRODUCTION The bluntnose sixgill shark Hexanchus griseus (Bonnaterre, 1788) is a deepwater, benthic, littoral and semi-pelagic shark (Compagno et al., 2005), listed as near threatened (NT) by the Red List of the International Union for Conservation of Nature (I.U.C.N.) (Finucci et al., 2020). Juveniles may approach the coast in cold water, while adults live in shallow waters close to sub- marine canyons (Compagno et al., 2005). H. griseus is found in the Pacific and Indian Oceans, off the eastern and western Atlantic coasts, and in the Mediterranean Sea (Bass et al., 1975), up to 1875 meters deep (Com- pagno et al., 2005). The bluntnose sixgill shark makes day and night excursions, moving from a depth of 250 m up to 20 m, near the surface (Andrews et al., 2009). The biology of H. griseus in the Mediterranean is poor- ly known and the little information published focuses mostly on its ichthyological characteristics (Capapé et al., 2003). Cases of hermaphroditism, although rare in elasmobranchs, seem to be present in bluntnose sixgill shark (Daniel, 1928). The maturity is reached at 309–330 cm of total length (TL) in males and 350–420 cm TL in females, while the maximum size reached is probably 550 cm TL (Compagno et al., 2005). In the present article, authors report an incident of a stranded bluntnose sixgill shark found on the Tuscan coast (cen- tral Tyrrhenian Sea) and provide information on the examined specimen. Furthermore, the authors review the occurrence status of H. griseus in the Mediterrane- an Sea in light of available data. MATERIAL AND METHODS On 16 March 2016, a bluntnose sixgill shark was found on the beach of Marina di Grosseto in Tuscany (coordinates: 42°43’24.5”N 10°58’19.4”E), Italy (Fig. 1a). This area, located in the northwestern Mediterra- nean, more precisely, in the central Tyrrhenian Sea, is characterised by a sandy bottom that slowly degrades Fig. 1: (A) Hexanchus griseus; (B) tooth measurement; (C) teeth; (D) MEDLEM report; (E) claspers; (F) damaged eye. Sl. 1: (A) Hexanchus griseus; (B) merjenje zob; (C) zobovje; (D) MEDLEM poročilo; (E) klasperja; (F) poškodovano oko. ANNALES · Ser. hist. nat. · 31 · 2021 · 1 33 Primo MICARELLI et al.: NOTES ON A RARE CASE OF BLUNTNOSE SIXGILL SHARK HEXANCHUS GRISEUS STRANDED ON THE COAST OF TUSCANY ..., 31–36 before reaching significant depths. The specimen, fo- und in late afternoon, was quickly collected and taken to landfill by the local authorities, thus only allowing for a collection of limited biometric data based on a few samples of teeth, and checking the external con- dition of the specimen. The shark was measured on the beach and its total length (TL) was recorded as a straight line extending from the tip of the snout to the tip of the upper lobe of the caudal fin, with the latter in the depressed position. This type of measurement represents the maximum length according to Compa- gno (1984). The available data were entered in the MEDLEM reporting form (Fig. 1d). RESULTS The male specimen displayed a pair of calcified claspers and was probably mature (Fig. 1e). Its size was 294 cm TL, it had no external abrasions or signs of capture by fishing gear; the mouth was free and without hooks. At the level of the left eye socket there was a deep horizontal cut and the eye was damaged (Fig. 1f). Six dental rows were observed and the dental formula 20/13 corresponded to that of H. griseus according to Last & Stevens (2009). Biometric analyses of two teeth A1 and A2 (Fig. 1c) of the front left region of the lower jaw were performed using a caliper (Fig. 1b). The biometric measurements, taken in mm, are shown in Table 1. The sixgill shark species H. griseus (Bonnaterre, 1788) and Hexanchus nakamurai (Teng, 1962) stand out for the presence of six rows of distinctly comb-shaped teeth in the lower jaw in the former and five rows in the latter species; moreover, H. griseus has a short, blunt, broadly rounded snout and a dorsal-caudal distance approximately equal to its dorsal fin base length, while H. nakamurai has a relatively longer snout that is more pointed and nar- row, and a dorsal-caudal distance that is much longer than the dorsal-fin base length (Ebert et al., 2013). In addition, Adnet (2006) stated that H. griseus and H. nakamurai are hard to distinguish, especially because of the similarity between the lower teeth of juvenile or sub-adult specimens in both species. DISCUSSION A historical survey of Mediterranean reports since 1892 shows that H. griseus has been captured in restricted areas of the western basin more common- ly than in the eastern one (Capapé et al., 2003). H. griseus is included in the I.U.C.N. Red List, and even though its populations are considered stable, they still require careful monitoring; in fact, species with similar life histories, often called ‘K-selected’ (Camhi et al., 1998), can be affected by deepwater fishery (Walls et al., 2015). Between 1666 and 2014, the MEDLEM (Serena et al., 2014) database for the Mediterranean Sea recorded occurrences of bluntnose sixgill shark (H. griseus) in Maltese waters (20 specimens; GSA 15); in the northern Tyrrhenian Sea (45 specimens; GSA 9); in the southern Adriatic Sea; in the northern Ionian Sea; in the southern waters of Sicily (21 specimens; GSA 18, 19, and 16 respectively); along the coasts of Tunisia (GSA 13 and 14) (Capapé et al., 2003; 2004); and in Turkish waters (24 specimens). The Mediterranean Sea has been divided into 30 geographical sub-areas, cal- led GSAs, by the General Fishery Commission for the Mediterranean - GFCM. Kabasakal (2013) states that 150 specimens of H. griseus were caught by commer- cial fishing vessels in the seas of Turkey between 1967 and 2013, 90 of which were recorded in the Marmara Sea. Based on an analysis of internet-based media reports on rare and large sharks of Turkey, Kabasakal & Bilecenoğlu (2020) indicated that nearly 52 percent (139 out of 268 specimens) of sharks captured between 2006 and 2020 were H. griseus. The bluntnose sixgill shark is also regularly captured along the coast of Lebanon (Lteif, 2015) and along the coasts of Calabria (21 specimens; GSA 10 and 19), (Leonetti et al., 2020). Stranding of bluntnose sixgill sharks in the Mediterra- nean Sea is rare, particularly in consideration of their presence at great depths. Kabasakal (2006) reported a female specimen (450 cm TL) stranded in the Dardanel- les Strait on 5 June 1999. Although in the present case it was not possible to collect all the samples needed to provide a more useful contribution to the knowledge of the biology of this species, it was nevertheless possible to establish that the number of rows of teeth equalled 6, which excluded the possibility that the shark could be a H. nakamurai, whose maximum TL does not Tab. 1: Five measurements were collected for each tooth: CH, crown height; RH, root height; TH, total height; BWT, basal width of the tooth; HC, height of the cusp. Tab. 1: Za vsak zob je bilo opravljenih pet meritev: CH, višina krone; RH, višina korenine; TH, celotna višina; BWT, bazalna širina zoba; HC, višina grbice. Biometric measurements of the teeth (mm) A1 A2 CH 10.3 9.84 RH 12.3 11.42 TH 19.97 19.49 BWT 28.99 28.06 HC 6.69 6.36 ANNALES · Ser. hist. nat. · 31 · 2021 · 1 34 Primo MICARELLI et al.: NOTES ON A RARE CASE OF BLUNTNOSE SIXGILL SHARK HEXANCHUS GRISEUS STRANDED ON THE COAST OF TUSCANY ..., 31–36 exceed 180 cm. It is important to remember that it is difficult to distinguish between specimens of the two species without precise information on their body size or maturity and only by comparing the teeth. In fact, Adnet (2006) showed that the two recent species of the genus Hexanchus have a similar dental development but with a different growth rate: at same tooth width, H. griseus retains a “young” morphology compared to that of H. nakamurai and the distinction between the two species in relation to dentition is currently limited to the presence, in some individuals, of a vertical median cusp on the symphyseal tooth in H. nakamurai, and dif- ferent dental formulae. The size of the stranded animal and the presence of hard and well-calcified claspers indicated its probable maturity, although its body size was slightly smaller than the minimum size at maturity indicated by Compagno et al. (2005), which is 309 cm for males. Observations suggest that H. griseus matures at a smaller size in the Mediterranean than elsewhere (Capapé et al., 2004). The examination of the collected teeth confirmed the equation for establishing the size of the animal based on the measurement of the tooth base. As a matter of fact, in large shark species such as H. griseus, the length of the body (Total Length according to Compagno, 1984) and the width of the teeth in each row are well correlated (R = from 0.95 to 0.98, p <0.001). A simple linear regression equation expresses the relationship between the width of the lower teeth and the length of the shark’s body, which can be calculated as follows: shark’s length (in cm) = 111 × tooth’s width (in cm) + 3.9 (R = 0.97, p <0.001; N = 243) (Adnet, 2006). If we were to apply the equa- tion in this instance, it would have been possible to estimate a length of about 325 cm, slightly greater than the measured one, thus confirming the correctness of the proposed equation. With regard to the reasons of the stranding, the absence of apparent damages from fishing tools and the presence of a deep cut at the eye level may suggest the possibility that this male specimen rose to the surface due to various reasons that could have also caused its death by ramming such as, for example, an accident with a boat. Injured sixgill sharks may be at risk for post-release or post-accident disability, or mortality due to long-term pathologic consequences of anthropogenically induced scars (Kabasakal, 2010). Andrews et al. (2009) found that in Puget Sound (USA), sixgill sharks showed consistent diel behavioural patterns throughout the year and inhabited greater depths during the day than during the night, being more active (with greater variation in depth and greater rates of vertical movement) at night. It is interesting to note that, in our case, the stranding occurred in March, right at the beginning of the spring season when, just like in Puget Sound, the movement to the surface of these sharks is more frequent. Seaso- nally, sixgill sharks occupy deeper habitats in autumn and winter than they do in spring, and are more active in autumn (Andrews et al., 2009). Moreover, in the Mediterranean, little is known about the behaviour of these sharks: Capapé et al. (2004) states that H. griseus is probably able to live and reproduce in the Mediter- ranean Sea; however, further observations are needed to confirm that a sustainable bluntnose sixgill shark population has been established here, especially off the Maghrebi coast. Incidental capture of a new-born specimen (60 cm TL) with an unhealed umbilical scar (birthmark) between the pectoral fins suggested the possibility of a nursery ground of H. griseus in northern Aegean Sea bathyal grounds (Kabasakal, 2013). More- over, another possible nursery ground was suggested in the Marmara Sea, where several juveniles (120 to 250 cm TL) were incidentally captured (Kabasakal, 2013). Finally, lack of information on the movements of the specimens along Turkish coasts reveals the necessity of tagging surveys of H. griseus in the mentioned region to understand the spatial and bathymetric movement patterns of this species (Kabasakal, 2013). Meager & Sumpton (2016) suggest that an integrated approach of using stranding and bycatch data may provide an indicator of long-term trends for data-limited cetace- ans, and that stranding programs can give a faithful representation of the species composition of cetacean assemblages, while standardised bycatch rates can provide a measure of relative abundance. Therefore, in the long term, the stranding of elasmobranchs, however rare and even in the case of animals living in the deep but periodically venturing to surface waters, could provide useful insights for an evaluation of their health status. This information provides a useful contri- bution to the biometric data available for this species, with particular reference to teeth, and testifies to a rare case of stranding. ANNALES · Ser. hist. nat. · 31 · 2021 · 1 35 Primo MICARELLI et al.: NOTES ON A RARE CASE OF BLUNTNOSE SIXGILL SHARK HEXANCHUS GRISEUS STRANDED ON THE COAST OF TUSCANY ..., 31–36 ZAPIS O REDKEM PRIMERU MORSKEGA PSA ŠESTEROŠKRGARJA HEXANCHUS GRISEUS, KI JE NASEDEL NA TOSKANSKI OBALI V OSREDNJEM TIRENSKEM MORJU Primo MICARELLI & Francesca Romana REINERO Centro Studi Squali – Istituto scientifico Loc. Valpiana Massa Marittima (GR), Italy e-mail: direzione@centrostudisquali.org Emilio SPERONE Dipartimento di Biologia, Ecologia e Scienze della Terra. Università della Calabria (CS), Italy POVZETEK Avtorji poročajo o redkem primeru, ko je na toskanski obali v osrednjem Tirenskem morju nasedel 297 cm dolg odrasel samec morskega psa šesteroškrgarja (Hexanchus griseus). Nasedli primerek je imel 6 nizov zob, po katerih ga je bilo možno razlikovati od sorodne vrste Hexanchus nakamurai, ki ima 5 nizov. Avtorji so opravili biometrijo na dveh zobeh levega sprednjega dela. Na telesu morskega psa ni bilo videti znakov ulova, le globoka rana v višini očesnega loka priča o morebitnem trku s plovilom. Ključne besede: morski pes šesteroškrgar, Hexanchus griseus, nasedli morski pes, zobovje, Sredozemsko morje ANNALES · Ser. hist. nat. · 31 · 2021 · 1 36 Primo MICARELLI et al.: NOTES ON A RARE CASE OF BLUNTNOSE SIXGILL SHARK HEXANCHUS GRISEUS STRANDED ON THE COAST OF TUSCANY ..., 31–36 REFERENCES Adnet, S. (2006): Biometric analysis of the teeth of fossil and Recent hexanchid sharks and its taxonomic implications. 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Elsevier. https://doi.org/10.1016/j.ecolind.2015.08.052 Serena, F., C. Mancusi & M. Barone (2014): Medi- terranean Large elasmobranch Monitoring. Protocollo di acquisizione dati. Sharklife program. Rome. 130 pp. Walls, R., A. Soldo, M. Bariche, E. Buscher, S.F. Cook & L.J.V. Compagno (2015): Hexanchus griseus. The IUCN Red List of Threatened Species 2015: e.T10030A48939463. Downloaded on 11 December 2020. ANNALES · Ser. hist. nat. · 31 · 2021 · 1 37 received: 2021-05-10 DOI 10.19233/ASHN.2021.06 THE OCCURRENCE OF THE COMMON ANGEL SHARK SQUATINA SQUATINA IN THE ADRIATIC SEA Alen SOLDO Department of Marine Studies, University of Split, Croatia e-mail: soldo@unist.hr ABSTRACT The common angel shark Squatina squatina is considered a critically endangered species in the Mediterra- nean, so much so that in Croatian Adriatic waters it deserves the highest level of protection. While in the 19th and the first half of the 20th century it was a common species here, it has been very rarely encountered over the last few decades. This paper aims to present the data on two additional records of S. squatina from the Adriatic and discuss its recent status with a proposal for effective management measures. Key words: angel sharks, Squatina squatina, critically endangered, Adriatic Sea, Mediterranean Sea PRESENZA DEL PESCE ANGELO SQUATINA SQUATINA IN ADRIATICO SINTESI Il pesce angelo Squatina squatina, specie in grave pericolo di estinzione nel Mediterraneo, merita il più alto livello di protezione nelle acque adriatiche croate. La specie, precedentemente comune nel 19° e nella prima metà del 20° secolo, è stata trovata molto raramente durante gli ultimi decenni. L’articolo mira a presentare i dati su due ritrovamenti aggiuntivi di S. squatina nell’Adriatico e a discutere il suo stato recente, con una proposta di misure di gestione efficaci. Parole chiave: pesce angelo, Squatina squatina, pericolo estinzione, Adriatico, Mediterraneo ANNALES · Ser. hist. nat. · 31 · 2021 · 1 38 Alen SOLDO: THE OCCURRENCE OF THE COMMON ANGEL SHARK SQUATINA SQUATINA IN THE ADRIATIC SEA, 37–44 INTRODUCTION Angel sharks are a group of at least 22 species, all in the genus Squatina (Ellis et al., 2020). Three species of angel shark are present in the Mediterranean with overlapping ranges. Of these, the sawback angelshark Squatina aculeata Cuvier 1829 is mainly documented in the central basin along the southern Mediterranean coast as far as the eastern basin, including the Aegean Sea (Başusta, 2002; Soldo & Bariche, 2016; Gordon et al., 2019), but not in the Adriatic Sea, while the other two species, the smoothback angel shark Squatina oculata Bonaparte, 1840 and the common angel shark Squatina squatina (Linnaeus, 1758), are reported as Adriatic species (Lipej et al., 2004). Angel sharks have dorso-ventrally flattened bodies and broad pectoral fins, which gives them a ray-like appearance. However, the anterior margins of the pectoral fins are not fused to the side of the head, and the five pairs of gill slits are lateral, not ventral, thus distinguishing angel sharks from rays (Compagno, 1984; Gordon et al., 2020). Unfortu- nately, the body shape and preference for coastal waters of many angel sharks makes them susceptible to capture by a variety of demersal fisheries, both commercial and recreational, from the very birth. As a result, angel sharks have been identified as one of the most threatened families of chondrichthyans (sharks, skates, rays, and chimaeras) in the world, with many requiring urgent conservation action (Dulvy et al., 2014). All three Mediterranean species are assessed as critically endangered in the Mediter- ranean due to past population declines, running an extremely high risk of extinction in the wild (Gordon et al., 2019). In relation to the Adriatic Sea, Brusina (1888) wrote that in the Gulf of Trieste and Dalmatia S. oculata was rarer than S. squatina; Jardas (1996) defined S. oculata as rare throughout the Adriatic Sea; and now, after several decades without any new records of S. oculata in the Adriatic, we can presume this species to be locally extinct. The body in S. squatina is strongly flattened dorso- ventrally, with a very wide head and very wide pec- toral and pelvic fins and no anal fin. The origin of the first dorsal fin is above the pelvic fin free rear tip, the caudal fin lower lobe larger than upper lobe. Nasal barbels are not fringed and spiracles are large. There are 5 pairs of gill slits, not visible when the shark rests on the sea bottom. Dorsal surface of light brown-gray color or dark with 1–3 straight dark bands on pectoral fins and small white and dark spots and dark patches; ventral surface white. Upper teeth with one cusp, small and pointed; lower teeth similar. S. squatina can reach a maximum size of 244 cm. The size at birth is 24–30 cm, at maturity the size of males is 80–132 cm, and of females 128–169 cm (Compagno, 1984; Lipej et al., 2004). Fig. 1: Capture and release site of two male specimens of S. squatina. Sl. 1: Mesto ulova in izpustitve dveh samcev sklata (S. squatina). ANNALES · Ser. hist. nat. · 31 · 2021 · 1 39 Alen SOLDO: THE OCCURRENCE OF THE COMMON ANGEL SHARK SQUATINA SQUATINA IN THE ADRIATIC SEA, 37–44 Brusina (1888) reported that (at his time) the common angel shark was abundantly caught in the Adriatic Sea. Jardas (1996) considered S. squatina to be rare throughout the Adriatic while only in the area of the Neretva River and Zadar did it seem to be more common. Bello (1999) wrote that the angel shark was infrequently caught in the southeastern part and rarely netted in the southwestern part of the Adriatic Sea. Matjašič et al. (1976) inserted S. squatina on the list of the fauna and flora of northern Adriatic. In the Kvarner region, this species was not registered between 1973 and 1996 (Jardas et al., 1998). Previous data indicate that S. squatina was often a by-catch of bottom trawls. Angel shark was reported as a caught species in 1948 during the Hvar expedition, but the Medits expedition which took place 50 years later, in 1998, failed to confirm the presence of this species (Jukić-Peladić et al., 2001). Soldo (2006) con- sidered both Adriatic angel shark species as very rare and critically endangered within the local area. Based on that opinion Croatia, within its waters, accorded both angel shark species the highest level of protection (strictly protected status) in the Adriatic. In Croatia, angel sharks were historically targeted, in fact, one of the large mesh size gillnets was called sklatara after the Croatian term for the angel shark – sklat. Something similar was indicated by Fortibuoni et al. (2016), who reported that according to naturalists’ accounts and historical documents, the species was so abundant in the Northern Adriatic in the 19th and early 20th centuries as to sustain targeted fisheries, and large quantities of S. squatina were sold in the main fish mar- kets, but during the 1960s, the species collapsed and became economically extinct. However, Fortibuoni et al. (2016) also concluded that even if S. squatina was never detected in the area during scientific sur- veys conducted between 1948 and 2014, it emerged from interviews with fishermen that the species is not extirpated from the Adriatic Sea. Such conclusion was also supported by occasional records from the Adriatic; Holcer & Lazar (2017), for example, reported 4 records from the 2008–2016 period (two from the Murter area and two from Kvarner). Thus, this paper aims to present new and older data on the occurrence of common angel shark in the Adri- atic and to discuss the recent status of this critically endangered species. MATERIAL AND METHODS The first specimen was caught on 8 March 2007 by a gillnet with 180 mm mesh size, at a depth of 50 m, near Point Križ – the Island of Sestrunj (Fig. 1). The second specimen was caught on 23 April 2021 with a trammel net at the depth of 23 m in front of Debeljak Bay, near Point Kamenjak (the southernmost tip of the Istrian Peninsula) (Fig. 1). The first specimen was caught and landed dead during a scientific survey, and therefore fully measured to the nearest mm and weighed to the nearest 0.01 g. After the dissection of the specimen, its stomach was isolated and examined. The second specimen was landed on a boat alive. The fisherman contacted the Pula Aquarium and their staff collected the specimen, taking it to the water tank in the aquarium, where it was kept alive. RESULTS Based on the diagnostic characteristics described by Compagno (1984) and Lipej et al. (2004), both specimens were identified as males of S. squatina. Mor- phometric measures of the first adult specimen (Fig. 2) taken according to the guidelines of Compagno (1984) are presented in Table 1. Tab. 1: Morphometric measurements of the specimen caught on 8 March 2007. Tab. 1: Morfometrične meritve primerka, ujetega 8. marca 2007. Morphometric parameter mm/g Total length - TOT 1080 Precaudal length - PRC 940 Pre-second dorsal length – PD2 825 Pre-first dorsal length – PD1 690 Preorbital length – POB 52 Prepectoral length – PP1 135 Preanal length – PAL 495 Dorsal caudal margin – CDM 160 Pectoral anterior margin – P1A 310 Pectoral base - P1B 160 Width with fins 635 Body width 245 Clasper inner length – CLI 165 Mouth width – MOW 135 Internarial space – INW 80 First dorsal height – D1H 95 First dorsal inner margin - D1L 80 First dorsal base – D1B 50 Total weight 11204 Liver weight 338 Stomach weight full 381 Stomach content weight 184 ANNALES · Ser. hist. nat. · 31 · 2021 · 1 40 Alen SOLDO: THE OCCURRENCE OF THE COMMON ANGEL SHARK SQUATINA SQUATINA IN THE ADRIATIC SEA, 37–44 The analysis of the stomach content revealed an omnivorous diet for S. squatina as the content included a whole black scorpionfish Scorpaena porcus Linnaeus 1758, remains of gilthead seabream Sparus aurata Linnaeus 1758, as well as several beaks of squid and cuttlefish. Leaves of seagrass Posidonia oceanica were also found in it, but it could not be concluded whether they had been ingested intentionally or accidentally during the pursuit of prey. Interestingly, this specimen was caught in the very Zadar archipelago area that had been historically identified as the habitat of the common angel shark. The second specimen was landed alive (Fig. 3) on a fishing boat on 23 April 2021 and transported and kept alive in the water tank of the Pula Aquarium. Their staff only performed basic measurements in order to keep the handling at a minimum and thus increase the specimen’s chances of recovery. This immature male measured 68 cm in length, 37 cm in width, and weighed 3.2 kg. After nearly two weeks in the Aquarium, the specimen successfully recovered and it was decided it should be released alive on 4 May 2021 in the adjacent waters of the Marine Protected Area of the National Park Brijuni (exact location known but not publicly available). DISCUSSION Historically, S. squatina was common across large areas of coastal, continental and insular shelves of the Northeast Atlantic (southern Norway to Western Sahara), and the Mediterranean and Black Seas. Nowadays, records of this species are reported throughout the Mediterranean including the south- ern coasts of the western and central basins, the Ligurian, Northern Tyrrhenian, and Adriatic Seas on the northern coast, and the Levant and Aegean Seas in the eastern basin (Gordon et al., 2019). It has also been documented in the Sea of Marmara and is the only angel shark species known to have been present in the Black Sea, with contemporary captures around the Bosporus Strait (Serena, 2005). However, although angel sharks are reported, their records are rare. Usually, these rely on fisher- ies data and reports of by-catch, as well as novel approaches such as citizen science, social media, and interviews with fishers aimed at increasing knowledge on distribution (Fortibuoni et al., 2016; Gordon et al., 2019). On the other hand, the use- fulness of scientific surveys, which are normally Fig. 2: The adult male specimen of S. squatina caught on 8 March 2007 by gillnet. Sl. 2: Odrasel samec sklata (S. squatina), ujet 8. marca 2007 v zabodno mrežo. ANNALES · Ser. hist. nat. · 31 · 2021 · 1 41 Alen SOLDO: THE OCCURRENCE OF THE COMMON ANGEL SHARK SQUATINA SQUATINA IN THE ADRIATIC SEA, 37–44 considered a good source of various data, has been questioned in relation to detection of rare species, due to a complete lack of data on angel sharks in scientific trawl surveys conducted in the Adriatic Sea since 1948 (Jukić-Peladić et al., 2001; Fortibuoni et al., 2016; Holcer & Lazar, 2017). An additional problem, quite common in the Mediterranean, is that frequently records from fisher- ies only classify angel sharks at genus level, which affects the possibility to determine the population status at species level. Precise data on angel sharks are thus hidden due to misreporting in fisheries or marketing under alternative common names. In many Mediterranean areas, angel sharks have been confused with other species, e.g. Lophius spp. or rays, particularly guitarfishes (species of the genus Rhinobatus). A recent analysis from the Adriatic Sea (Bakiu & Soldo, 2021) pointed to the reported landing of angel sharks and sand devils nei group (Squatinidae) in Albania. This Adriatic country was regularly reporting angel shark catches, with the largest catch stated in 2010 (78 tons). The last report dates to 2016, when a catch of 3 tons was declared. However, after conducting a scientific survey on shark catches, including interviews with fishermen, Bakiu & Soldo (2021) concluded that the reported catches were likely misidentified, like presumably in some other Mediterranean countries (Gordon et al., 2019). Given the critically endangered status of angel sharks in the Mediterranean, there are several exist- ing protective measures that can be implemented for these species. In a binding Recommendation adopted by the 24 parties to the GFCM (GFCM/36/2012/3, amended to GFCM 42/2018/2) it has been agreed that retention and sale of 24 elasmobranchs listed in Annex II of the Barcelona Convention, includ- ing all three species of the Mediterranean angel shark, should be prohibited. The European Union (EU) transposed the GFCM Recommendation into EU Regulation (EU 2015/2102), prohibiting the retention of all three species of angel shark in the Mediterranean and augmenting the prior listing of S. squatina as a prohibited species under the Common Fisheries Policy annual fisheries quotas (Gordon et al., 2019). However, the implementation of full pro- tection measures at national levels by EU Member States has been poor. A positive example is Croatia, Fig. 3: The immature male specimen of S. squatina caught and landed alive on 23 April 2021. Sl. 3: Mladostni primerek sklata (S. squatina), ki je bil ujet in izpuščen 23. aprila 2021. ANNALES · Ser. hist. nat. · 31 · 2021 · 1 42 Alen SOLDO: THE OCCURRENCE OF THE COMMON ANGEL SHARK SQUATINA SQUATINA IN THE ADRIATIC SEA, 37–44 which is recognized as a champion in the protec- tion of sharks and rays. The group of 28 species of sharks and rays that have been declared as strictly protected species, includes both Adriatic angels sharks. Nevertheless, being granted the maximum level of protection alone will not prevent the spe- cies from being caught, especially the angel sharks inhabiting the inshore area, where the fishing effort and the use of a broad range of bottom fishing gear in small- and large-scale fisheries are the most ex- tensive. Therefore, the efforts of conservation action should not stop at the implementation of relevant international and regional obligations into national legislation, as fishery within angels sharks’ habitats will continue. Although the results of this paper show that some angel sharks can indeed be landed alive and subsequently released back into the sea, proper management cannot rely on the possibility that the shark will be landed on a boat in good con- dition and that the fishermen involved will have the incentive and be motivated to release the protected species properly. Thus, the vital conservation issue is, after the implementation of conservation meas- ures into national legislation, to identify and map the critical habitats occupied by angel sharks. As it can be presumed that those habitats will be defined within the inshore area, where proclaiming a marine protected area is a very sensitive and lengthy (if even possible) process, with different responsibilities, au- thorities, and interests overlapping, usually between fishery and environmental protection administration, the goal should be to determine limited, but large enough habitats where the use of bottom fishing gear will be restricted exclusively to the selective gear that cannot be used to target angel sharks. Having a protected area where the use of large mesh size gillnets and trammel nets, as well as towing fishing gear (which is completely unselective to relatively larger marine species) will be forbidden could result in giving a chance to angel shark populations to re- cover from depletion and hopefully reach the levels where they would not be endangered anymore. ACKNOWLEDGMENTS I would like to express my sincere gratitude to the staff of the Aquarium Pula, led by Milena Mičić, for providing the data on a caught specimen and especially for their enthusiasm and effort in saving and releasing the specimen alive. ANNALES · Ser. hist. nat. · 31 · 2021 · 1 43 Alen SOLDO: THE OCCURRENCE OF THE COMMON ANGEL SHARK SQUATINA SQUATINA IN THE ADRIATIC SEA, 37–44 POJAVLJANJE NAVADNEGA SKLATA (SQUATINA SQUATINA) V JADRANSKEM MORJU Alen SOLDO Department of Marine Studies, University of Split, Croatia e-mail: soldo@unist.hr POVZETEK Navadni sklat (Squatina squatina), danes opredeljen kot kritično ogrožena vrsta v Sredozemskem morju, ima v hrvaškem delu Jadrana najvišji nivo varovanja. To, še v 19. in 20. stoletju pogosto vrsto, so v zadnjih desetletjih le redko ujeli. Avtor v pričujočem prispevku poroča o dveh primerih ulova navadnega sklata v Jadranskem morju in razpravlja o njegovem trenutnem statusu ter predlaga učinkovite mere upravljanja z vrsto. Ključne besede: sklati, Squatina squatina, kritično ogrožena vrsta, Jadransko morje, Sredozemsko morje ANNALES · Ser. hist. nat. · 31 · 2021 · 1 44 Alen SOLDO: THE OCCURRENCE OF THE COMMON ANGEL SHARK SQUATINA SQUATINA IN THE ADRIATIC SEA, 37–44 REFERENCES Bakiu, R & A. Soldo (2021): Shark capture by commer- cial fisheries in Albania. J. Appl Ichthyol., 00, 1– 4. Başusta, N. (2002): Occurrence of a sawback an- gelshark (Squatina aculeata Cuvier, 1829) off the eastern Mediterranean Coast of Turkey. Turk. J. Vet. Anim. Sci., 26, 1177-1179. Bello, G. (1999): The Chondrichthyans of the Adriatic sea. Acta Adriatica, 40(1), 65-76. Brusina, S. (1888): Morski psi Sredozemnoga i Crljenog mora (Sharks of the Adriatic and the Black Sea). Glasnik hrvatskoga naravoslovnoga družtva, Zagreb, III, 167-230. (In Croatian). Compagno, L.J.V. (1984): FAO species catalogue. Sharks of the world. An annotated and illustrated catalogue of shark species known to date. Part 1. Hexanchiformes to Lamni- formes. FAO Fish Synop. No. 125, Vol. 4, 250 pp. Dulvy, N.K., S.L. Fowler, J.A. Musick, R.D. Cavanagh, P.M. Kyne, L.R. Harrison, J.K. Carlson, L.N. Davidson, S.V. Fordham, M.P. Francis, C.M. Pollock, C.A. Simpfendorfer, G.H. Burgess, K.E. Carpenter, L.J. Compagno, D.A. Ebert, C. Gibson, M.R. Heupel, S.R. Livingstone, J.C. Sanciangco, J.D. Stevens, S. Valenti & W.T. White (2014): Extinction risk and conservation of the world’s sharks and rays. eLife, 3, e00590. Ellis, J.R., Barker, J., McCully Phillips, S.R., Meyers, E.K.M. & M. Heupel (2020): Angel sharks (Squatinidae): A review of biological knowledge and exploitation. J. Fish. Biol., 98, 592-621. Fortibuoni, T., D. Borme, G. Franceschini, O. Gio- vanardi & S. Raicevich (2016): Common, rare or extirpat- ed? Shifting baselines for common angelshark, Squatina squatina (Elasmobranchii: Squatinidae), in the Northern Adriatic Sea (Mediterranean Sea). Hydrobiologia, 772(1), 247-59. Gordon, C.A., A.R. Hood, S.A.A. Al Mabruk, J. Barker, A. Bartolí, S. Ben Abdelhamid, M.N. Bradai, N.K. Dulvy, T. Fortibuoni, I. Giovos, D. Jimenez Alvarado, E.K.M. Meyers, G. Morey, S. Niedermuller, A. Pauly, F. Serena & M. Vacchi (2019): Mediterranean Angel Sharks: Regional Action Plan. The Shark Trust, United Kingdom. 36 pp. Holcer, D. & B. Lazar (2017): New data on the occur- rence of the critically endangered common angelshark, Squatina squatina, in the Croatian Adriatic Sea. Nat. Croat., 26(2), 313-320. Jardas, I. (1996): Jadranska ihtiofauna. Školska knjiga Zagreb. (In Croatian with English summary), 533 pp. Jardas, I. , A. Pallaoro & M. Kovačić (1998): Recent ich- thyofauna of the Rijeka Bay. In: Arko-Pijevac, Kovačić, M. & D. Crnković (eds.) Natural History researches of the Rijeka region. Ed. Natural History Library, Rijeka, pp. 671-684. Jukić-Peladić, S., N. Vrgoč, S. Krstulović-Šifner, C. Piccinetti, G. Piccinetti-Manfrin, G. Marano & N. Ungaro (2001): Long-term changes in demersal resources of the Adriatic Sea: comparison between trawl surveys carried out in 1948 and 1998. Fisheries research, 53, 95-104. Lipej, L., A. De Maddalena & A. Soldo (2004): Sharks of the Adriatic Sea. Knjižnica Annales Majora, Koper, 254 pp. Matjašič, J., J. Štirn, A. Avčin, L. Kubik, T. Valentinčič, F. Velkovrh & A. Vukovič (1976): Flora in favna severnega Jadrana. Slovenska Akademija Znanosti in Umetnosti. Raz- red za prirodoslovne vede, 54 pp. (In Slovenian). Serena, F. (2005): Field Identification Guide to the Sharks and Rays of the Mediterranean and Black Sea. FAO Species Identification Guide for Fishery Purposes, FAO, Rome. Soldo, A. (2006): Current status of the sharks in the east- ern Adriatic. Cetaceans, sea turtles and sharks of the Adriatic Sea – Cattolica (RN), Italy – 27-28 Oct. 2006. Conference Proceedings, 8 pp. Soldo, A. & M. Bariche (2016): Squatina acu- leata. The IUCN Red List of Threatened Species 2016: e.T61417A16569265. Downloaded on 06 May 2021. ANNALES · Ser. hist. nat. · 31 · 2021 · 1 45 received: 2020-11-09 DOI 10.19233/ASHN.2021.07 INTENTIONAL STRANDING OF A BLUE SHARK, PRIONACE GLAUCA (CARCHARHINIFORMES: CARCHARHINIDAE), IN PURSUIT OF PREY Hakan KABASAKAL Ichthyological Research Society, Tantavi mahallesi, Menteşoğlu caddesi, İdil ap., No:30, D: 4, 34764 Ümraniye, İstanbul, Turkey e-mail: kabasakal.hakan@gmail.com Deniz AYAS Faculty of Fisheries, Mersin University Yenişehir Campus, 33160, Mersin, Turkey Deniz ERGÜDEN İskenderun Technical University, Marine Sciences and Technology Faculty, Marine Sciences Department, İskenderun, Hatay, Turkey ABSTRACT A short video recorded by a resident on 22 October 2020, on the Tisan-Yeşilovacık coast (northeastern Medi- terranean), revealed the intentional stranding of a large specimen of Prionace glauca in order to pursue prey. Intentional stranding is a hunting strategy that differs from the blue shark’s usual feeding behaviour; however, the reported event was nothing more than a lucky coincidence that shed a different light on the hunting behaviour of P. glauca. Moreover, the present incident is crucial as it shows that large shark species living in open waters can enter coastal waters for feeding purposes, increasing the likelihood of dangerous encounters with humans. Key words: Prionace glauca, blue shark, stranding, hunting, coastal waters, eastern Levant INCAGLIO INTENZIONALE DI UNA VERDESCA, PRIONACE GLAUCA (CARCHARHINIFORMES: CARCHARHINIDAE), ALL’INSEGUIMENTO DELLA PREDA SINTESI Un breve video registrato da un residente il 22 ottobre 2020, lungo la costa di Tisan-Yeşilovacık (Mediterraneo nord-orientale), ha rivelato l’incaglio intenzionale di un grosso esemplare di Prionace glauca, per inseguire una preda. L’arenamento intenzionale è una strategia di caccia che differisce dall’usuale comportamento alimentare della verdesca. Tuttavia, l’evento riportato non è stato altro che una fortunata coincidenza che ha gettato una luce diversa sul comportamento di caccia di P. glauca. Il presente incidente è inoltre cruciale in quanto dimostra che le grandi specie di squali che vivono in acque aperte possono entrare nelle acque costiere per nutrirsi, aumentando la probabilità di incontri pericolosi con l’uomo. Parole chiave: Prionace glauca, verdesca, incaglio, caccia, acque costiere, Levante orientale ANNALES · Ser. hist. nat. · 31 · 2021 · 1 46 Hakan KABASAKAL et al.: INTENTIONAL STRANDING OF A BLUE SHARK, PRIONACE GLAUCA (CARCHARHINIFORMES: CARCHARHINIDAE), IN PURSUIT OF PREY, 45–50 INTRODUCTION The blue shark, Prionace glauca (Linnaeus, 1758), is an oceanic and circumglobal shark inhabiting tem- perate and tropical waters (Ebert & Stehmann, 2013). It is probably the widest-ranging chondrichthyan and nomad of the oceans, occurring from surface to at least 350 m in depth (Ebert & Stehmann, 2013). P. glauca is one of the well-documented pelagic sharks of the Mediterranean Sea (Serena et al., 2020). His- torically, the Mediterranean distribution of the blue shark extended into the Sea of Marmara, at least dur- ing the first quarter of the 20th century (Ninni, 1923), where it is now considered to be extinct (Kabasakal, 2020). Small fishes and cephalopods, especially squids, associated with pelagic and inshore habitats, com- pose the primary prey of P. glauca (Tricas, 1979; Ebert & Stehmann, 2013). Although P. glauca is mainly an oceanic shark (Ebert & Stehmann, 2013), its coastal occurrences in very shallow waters have also been documented (Kabasakal, 2010); however, intentional stranding of the blue shark has not been observed previously. In the present article, the authors report on an incident of intentional stranding of a large P. glauca specimen in pursuit of prey. Intentional stranding is a conspicuous hunting strategy, which is mostly observed in killer whales, Orcinus orca, when hunting for elephant seal pups, in pursuit of prey, the hunter swims directly to the surf zone and intentionally strands itself (Guinet & Bouvier, 1995). MATERIAL AND METHODS On 22 October 2020, a short (22 second) video of the present incident of intentional stranding of blue shark was recorded on the Tisan-Yeşilovacık coast (northeastern Mediterranean; Fig. 1) by a resident, Mr. Mustafa Çınar. The footage was emailed to the second author, who forwarded it to the first author to confirm species identification and analyses of the feeding behaviour. Species identification is based on the field marks provided by Ebert and Stehmann (2013). Feeding responses of the present blue shark were based on the feeding behaviour of P. glauca described by Tricas (1979). The footage has been archived by the authors and is available for further inspection on request. Fig. 1: Map depicting the approximate location (*) of the blue shark’s intentional stranding on the Tisan-Yeşilovacık coast, northeastern Mediterranean Sea. Sl. 1: Zemljevid obravnavanega območja s približno lokaliteto (*), kjer je namerno nasedel sinji morski pes ob obali Tisan-Yeşilovacık v severovzhodnem Sredozemskem morju. ANNALES · Ser. hist. nat. · 31 · 2021 · 1 47 Hakan KABASAKAL et al.: INTENTIONAL STRANDING OF A BLUE SHARK, PRIONACE GLAUCA (CARCHARHINIFORMES: CARCHARHINIDAE), IN PURSUIT OF PREY, 45–50 RESULTS AND DISCUSSION Dorsal coloration of the present specimen is dark blue, turning brighter on sides (Fig. 2); body slender (Fig. 2a, e, f) with long, pointed pectoral fins (Fig. 2e, f); the first dorsal fin is almost on the mid-body, but slightly closer to the pectoral-fin bases than the pelvic fins (Fig. 2a, e); the second dorsal fin is remarkably smaller than the first one (Fig. 2a); the caudal fin is narrow-lobed (Fig. 2a). The observed characters co- incided with the field marks of P. glauca, presented by Ebert and Stehmann (2013). The total length of the shark was estimated to be 200 cm. During the first seconds of the video, the blue shark was observed accelerating in a straight line (charging) into the swash zone (Fig. 2a, b), then turn- ing in an alert state, and subsequently starting a series of slow to fast lateral head swaying movements (Fig. 2c). The head swaying lasted nearly 11 seconds and was performed in an intentionally stranded status in the swash zone (Fig. 2b, c, d, e). During that time a fish, probably the prey, was seen moving around the blue shark’s head (Fig. 2d, e). The shark made sev- eral unsuccessful attempts at grabbing it, then turned to the seaboard and moved away (Fig. 2f). The total duration of the observed intentional stranding of the blue shark was 17 seconds. Killer whales, Orcinus orca (Linnaeus, 1758), are known for employing intentional stranding tech- niques when hunting sea lions and seals (Guinet & Bouvier, 1995; Vila et al., 2008). Intentional stranding observed in O. orca is a very specialised hunting strat- egy. Juvenile killer whales practice it for a remarkably long time, learning through apprenticeship (Guinet Fig. 2: Sequentially captured images of intentional stranding of a P. glauca during hunting: (a) charging of the blue shark; (b) bending tail and body just before turning; (c) turning; (d, e) head swaying; and (f) turning and moving away from the swash zone (Video footage courtesy of Mr. Mustafa Çınar). Sl. 2: Zaporedni posnetki namernega nasedanja sinjega morskega psa P. glauca med lovom: (a) priprava; (b) zvijanje repa in telesa tik pred obratom; (c) obrat; (d, e) zibanje glave; in (f) obrat in umik iz obrežnega pasu (avtor posnetka: Mr. Mustafa Çınar). ANNALES · Ser. hist. nat. · 31 · 2021 · 1 48 Hakan KABASAKAL et al.: INTENTIONAL STRANDING OF A BLUE SHARK, PRIONACE GLAUCA (CARCHARHINIFORMES: CARCHARHINIDAE), IN PURSUIT OF PREY, 45–50 & Bouvier, 1995). Previous studies have shown that beaching play is an essential step in a successful intentional stranding of the killer whale, allowing the capture of prey (Guinet & Bouvier, 1995). Since no beaching play was observed in the present incident, the intentional stranding of the blue shark likely re- sulted from the predator’s charging in the direction of the shoreline in too shallow coastal waters. In an extensive survey on the feeding behaviour of P. glauca, near Santa Catalina Island, California (Tricas, 1979), underwater observation of blue shark during hunting revealed four feeding responses, namely, slow head swaying, turning, charging, and tail standing. In the present incident we observed three of the four feeding movements, all except the tail standing, which in the mentioned survey mani- fested with the shark first circling the lower portion of a school of prey, then moving up to the prey and assuming a near-vertical attitude, using broad tail sweeps to maintain position (Tricas, 1979). Since the blue shark in our case intentionally stranded, the tail standing was not possible; however, a quick sequence of charging, turning, head swaying, and turning again before the blue shark left the swash zone, was observed (Fig. 2). Although P. glauca is an oceanic shark, frequently in pursuit of pelagic prey (Tricas, 1979; Ebert & Stehmann, 2013), the present incident suggests that it may occasionally use the intentional stranding technique to feed on coastal prey. Feeding was also reported as a possible reason for the unusual pres- ence of P. glauca recruits in Galician coastal waters (Bañón et al., 2016). The presence of coastal organ- isms has been observed in stomach contents of the blue shark. Tricas (1979) reported the presence of fishes associated with coastal habitats, such as the jack mackerel (Trachurus symmetricus), the pipefish (Syngnathus californiensis), and the blacksmith (Chromis punctipinnis), in the stomach contents of a P. glauca sampled in Californian waters. Kabasakal (2010) observed the remains of goatfish (Mullus sp.) and cuttlefish (Sepia sp.) in the stomach content of a juvenile blue shark (98 cm TL) incidentally caught in the shallow waters of Edremit Bay (northeastern Aegean Sea). The present incident of intentional stranding was a display of hunting strategy differing from the blue shark’s usual feeding behaviour ((Tricas, 1979). It was, generally speaking, nothing more than a lucky coincidence, which nevertheless provided a different perspective to the hunting behaviour of P. glauca. Although the blue shark is not very aggressive, it is not very timid either and has been known to harass spearfishing divers (Ebert & Stehmann, 2013). It is recognised that, besides P. glauca, several other large shark species, such as the shortfin mako shark (Isurus oxyrinchus) and the sandbar shark (Carcharhinus plumbeus), can also be seen in the coastal waters of the study area. Due to intensive fishing and aquacul- ture activities in the region the possibility of human encounter with large predatory sharks may be increas- ing. In a recent encounter of this kind with sandbar sharks, aquaculture divers have been involved in a provoked attack (Ergüden et al., 2020). The present incident is important as it shows that large shark spe- cies living in open waters can enter coastal waters for feeding purposes, and this increases the likelihood of dangerous encounters with humans. Although P. glauca is the most common shark in the eastern Mediterranean (Bariche, 2012; Damalas & Megalofonou, 2012), it is considered critically endangered in the Mediterranean Sea due to by- catching in pelagic fisheries (Otero et al., 2019). Therefore, monitoring the existence and seasonality of large shark species, such as P. glauca, occurring in the region, especially near aquaculture cages, is of great importance in terms of both the survival of shark species and the safety of people. ACKNOWLEDGMENTS The authors thank to Mr. Mustafa Çınar for pro- viding the footage of an intentionally stranded blue shark. ANNALES · Ser. hist. nat. · 31 · 2021 · 1 49 Hakan KABASAKAL et al.: INTENTIONAL STRANDING OF A BLUE SHARK, PRIONACE GLAUCA (CARCHARHINIFORMES: CARCHARHINIDAE), IN PURSUIT OF PREY, 45–50 NAMERNO NASEDANJE SINJEGA MORSKEGA PSA, PRIONACE GLAUCA (CARCHARHINIFORMES: CARCHARHINIDAE), MED ZASLEDOVANJEM PLENA Hakan KABASAKAL Ichthyological Research Society, Tantavi mahallesi, Menteşoğlu caddesi, İdil ap., No:30, D: 4, 34764 Ümraniye, İstanbul, Turkey e-mail: kabasakal.hakan@gmail.com Deniz AYAS Faculty of Fisheries, Mersin University Yenişehir Campus, 33160, Mersin, Turkey Deniz ERGÜDEN İskenderun Technical University, Marine Sciences and Technology Faculty, Marine Sciences Department, İskenderun, Hatay, Turkey POVZETEK Domačin z obale Tisan-Yeşilovacık (severovzhodno Sredozemsko morje) je 22. oktobra 2020 posnel krajši videoposnetek o namernem nasedanju velikega primerka sinjega morskega psa, Prionace glauca, ki je zasle- doval plen. Namerno nasedanje je plenilska strategija, drugačna od običajnega plenjenja. Slučajna in srečna okoliščina, v kateri je nastal posnetek, je obelodanila nenavadno vedenje. Poleg tega je ta primer pomemben, ker je pokazal da lahko odprtovodni morski psi lahko zaidejo v obalne vode zaradi prehranjevanja, s tem pa do večje možnosti nevarnih srečanj s človekom. Ključne besede: Prionace glauca, sinji morski pes, nasedanje, lov, obalne vode, vzhodni Levant ANNALES · Ser. hist. nat. · 31 · 2021 · 1 50 Hakan KABASAKAL et al.: INTENTIONAL STRANDING OF A BLUE SHARK, PRIONACE GLAUCA (CARCHARHINIFORMES: CARCHARHINIDAE), IN PURSUIT OF PREY, 45–50 REFERENCES Bañón, R., T. Maño & G. Mucientes (2016): Observa- tions of newborn blue sharks Prionace glauca in shallow inshore waters of the north-east Atlantic Ocean. J. Fish Biol., doi:10.1111/jfb.13082 Bariche, M. (2012): Field identification guide to the living marine resources of the Eastern and Southern Medi- terranean. FAO Species Identification Guide for Fishery Purposes. Rome, FAO, 610 p. Damalas, D. & P. Megalofonou (2012): Occurrences of large sharks in the open waters of the southeastern Medi- terranean Sea. J. Nat. Hist., 46, 2701-2723. Ebert, D.A. & M.F.W. Stehmann (2013): Sharks, ba- toids and chimaeras of the North Atlantic. FAO Species Catalogue for Fishery Purposes. No. 7. FAO, Rome, 523 p. Ergüden, D., D. Ayas & H. Kabasakal (2020): Provoked non-fatal attacks to divers by sandbar shark, Carcharhi- nus plumbeus (Carcharhiniformes: Carcharhinidae), off Taşucu coast (NE Mediterranean Sea, Turkey). Annales Ser. Hist. Nat., 30, 1-8. Guinet, C. & J. Bouvier (1995): Development of intentional stranding hunting techniques in killer whale (Orcinus orca) calves at Crozet Archipelago. Can. J. Zool., 73, 27-33. Kabasakal H. (2010): On the occurrence of the blue shark, Prionace glauca (Chondrichthyes: Carcharhinidae), off Turkish coast of northern Aegean Sea. Mar. Biodivers. 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(1979): Relationships of the blue shark, Prionace glauca, and its prey species near Santa Catalina Island, California. Fish. Bull., 77, 175-182. Vila, A. R., C. Campana, M. Iñíguez & V. Falabella (2008): South American sea lions (Otaria flavescens) avoid killer whale (Orcinus orca) predation. Aquat. Mamm., 34, 317-330. ANNALES · Ser. hist. nat. · 31 · 2021 · 1 51 received: 2021-04-20 DOI 10.19233/ASHN.2021.08 USING CITIZEN SCIENCE TO DETECT RARE AND ENDANGERED SPECIES: NEW RECORDS OF THE GREAT WHITE SHARK CARCHARODON CARCHARIAS OFF THE LIBYAN COAST Patrick L. JAMBURA & Julia TÜRTSCHER University of Vienna, Department of Palaeontology, Vienna 1090, Austria, e-mail: patrick.jambura@gmail.com Alessandro DE MADDALENA Shark Museum, Cape Town 7995, South Africa Ioannis GIOVOS iSea, Environmental Organization for the Preservation of the Aquatic Ecosystems, Thessaloniki 54645, Greece Jürgen KRIWET University of Vienna, Department of Palaeontology, Vienna 1090, Austria Jamila RIZGALLA University of Tripoli, Faculty of Agriculture, Department of Aquaculture, Tripoli, Libya Sara A. A. AL MABRUK Higher institute of Science and Technology, Department of General Nursing Technology, Cyrene, Libya Marine Biology in Libya Society, El Bayda, Libya ABSTRACT The presence of the great white shark (Carcharodon carcharias) in the Mediterranean Sea is well documented, but encounters with this species are rare and all assumptions about its spatial and temporal distribution are heavily relying on anecdotal observations. To date, only one record off the Libyan coast has been reported, raising the question if this species is underreported in these waters or simply represents a rare occasional transient. We utilised citizen science-sourced data to document the presence of the great white shark off the Libyan coast, and found six additional records for this species from the period between 2017 and 2020. Our study points out the need for scientific monitoring of this species along the Libyan coast to facilitate the establishment of effective conservation plans to protect this critically endangered species. Key words: Elasmobranchii, cartilaginous fish, conservation biology, fisheries, social media, threatened species USO DELLA SCIENZA DEL CITTADINO PER INDIVIDUARE SPECIE RARE E IN PERICOLO: NUOVI RITROVAMENTI DEL GRANDE SQUALO BIANCO CARCHARODON CARCHARIAS AL LARGO DELLA COSTA LIBICA SINTESI La presenza del grande squalo bianco (Carcharodon carcharias) nel Mediterraneo è ben documentata, ma gli incontri con questa specie sono rari e tutte le ipotesi sulla sua distribuzione spaziale e temporale sono fortemente basate su osservazioni aneddotiche. Fino ad oggi, è stato riportato un solo avvistamento al largo della costa libica, portando alla domanda se questa specie sia sotto-segnalata in queste acque o semplicemente rappresenti un raro transitorio occasionale. Gli autori hanno utilizzato i dati forniti dai cittadini per documentare la presenza del grande squalo bianco al largo della costa libica. Hanno trovato dati inerenti sei avvistamenti aggiuntivi di questa specie tra il 2017 e il 2020. Lo studio sottolinea la necessità di un monitoraggio scientifico di questa specie lungo la costa libica per facilitare l’istituzione di piani di conservazione efficaci per proteggere questa specie minacciata. Parole chiave: Elasmobranchii, pesci cartilaginei, biologia della conservazione, pesca, social media, specie minacciate ANNALES · Ser. hist. nat. · 31 · 2021 · 1 52 Patrick L. JAMBURA et al.: USING CITIZEN SCIENCE TO DETECT RARE AND ENDANGERED SPECIES: NEW RECORDS OF THE GREAT WHITE SHARK ..., 51–60 INTRODUCTION The great white shark Carcharodon carcharias (L., 1758) is, with a total length of at least six meters (Randall, 1973; Castro, 2012), one of the largest marine predators worldwide. This cosmopolitan species inhabits mainly temperate and subtropical waters, with adult individuals rarely entering tropi- cal waters (Compagno, 2001). In the Mediterranean Sea, white sharks have been frequently reported from the Strait of Sicily (Storai et al., 2000; Ben- Amor et al., 2020; Tiralongo et al., 2020), the Tyrrhenian Sea (Storai et al., 2000), the Gulf of Lions (De Maddalena & Zuffa, 2009), the Balearic Islands (Morey et al., 2003), the Adriatic Sea (De Maddalena, 2000; Soldo & Jardas, 2002), the Ionian Sea (Papaconstantinou, 2014), the Marmara Sea, including the Bosphorus Strait (Kabasakal, 2003, 2014, 2016), and the Aegean Sea (Kabasakal, 2014, 2016, 2019; Papaconstantinou, 2014). Based on the occurrence of neonates, small juveniles and preg- nant females, the existence of two possible nursery areas has been proposed in the Mediterranean Sea, one in the Strait of Sicily, Central Mediterranean Sea (Fergusson, 1996; Saïdi et al., 2005; Bradaï & Saïdi, 2013) and another in Edremit Bay, northern Aegean Sea (Kabasakal, 2016, 2020a,b). Molecular studies examining the genetic profile of white sharks via the mt-DNA control region have revealed the presence of an isolated Mediterranean population, which exhibits little genetic variability and only has limited genetic exchange with the At- lantic population (Gubili et al., 2011; 2015; Leone et al., 2020). This lack of genetic diversity coupled with little or no contemporary immigration from the Atlantic renders the Mediterranean popula- tion extraordinarily prone to extinction (Gubili et al., 2011; 2015). According to the IUCN Red List of Threatened Species, white sharks are declared globally vulnerable (VU; Rigby et al., 2019), while the Mediterranean population is listed as critically endangered (CR; Soldo et al., 2016). In an attempt to assess population trends and dynamics for white sharks in the Mediterranean, Moro et al. (2020) compiled a comprehensive database of 773 white shark records between 1860 and 2016 and found a 52–96% overall population decline in different Mediterranean sectors and a contraction in spatial distribution. It should be noted that encounters with white sharks in the Mediterranean Sea are usu- ally rare and very sporadic in nature. Therefore, all hypotheses about distribution, migration patterns, parturition, and the conservation status of white sharks in the Mediterranean Sea rely on anecdotal observations, like historical captures and sighting data (Fergusson, 1996; De Maddalena & Heim, 2012; Boldrochhi et al., 2017; Moro et al., 2020). Due to insufficient fishery data for many shark spe- cies, especially rare ones (Damalas & Megalofonou, 2012; Cashion et al., 2019), and the absence of coordinated scientific surveys, citizen science has frequently been used to monitor the presence of rare shark species in the Mediterranean Sea (e.g., Giovos et al., 2019; Kabasakal & Bilecenoğlu, 2020; Jambura et al., 2021). Landing almost 4.3 tonnes of chondrichthyan fishes in 2015, Libya is the leading country for chondrichthyan catches in the Mediterranean Sea (Jeffries, 2019). However, little is known about the presence of white sharks in Libyan waters and only a single record of a large female white shark off the Libyan coast does exist (Galaz & De Maddalena, 2004). Assessing the presence of white sharks in Lib- yan waters is, consequently, of utmost importance for future conservation planning of this iconic shark species. In our study, a systematic online search on popular social media platforms (i.e., Facebook, YouTube, Instagram, and Twitter) was conducted to document the presence of the great white shark C. carcharias along the Libyan coast and to augment our understanding of the distribution and ecology of this rare species in the Mediterranean Sea. MATERIAL AND METHODS Records of white shark C. carcharias off the Lib- yan coast were accumulated within the context of the citizen-science initiative “Monitoring Elasmo- branchii in Libyan Waters”, which was conducted by “Marine Biology in Libya”. This programme puts a focus on the occurrence of chondrichthyan fishes in the Mediterranean Sea and applies a verified citizen science model, in which citizen- submitted observations are checked by experts (Gardiner et al., 2012). The records either came directly from fishermen reporting their catch, or through systematic online searches on social media platforms, namely Facebook, YouTube, Instagram, and Twitter using the Arabic keyword for great white shark ( species in the Mediterranean Sea (e.g., Giovos et al., 2019; Kabasakal & Bilecenoğlu, 2020; Jambura et al., 2021). Landing almost 4.3 tonnes of chondrichthyan fishes in 2015, Libya is the leading country for chondrichthyan catches in the Mediterranean Sea (Jeffries, 2019). However, little is known about the presence of white sharks in Libyan waters and only one single record of a large female white shark off the Libyan coast does exist (Galaz & De Maddalena, 2004). Assessing the presence of white sharks in Libyan waters is, consequently, of utmost importance for future conservation planning of this iconic shark species. In our study, a systematic online search on popular social media pl tforms (i.e., Faceb ok, YouTube, Instagram, and Twitter) was conducted to document the presence of the great white shark C. carcharias along the Libyan coast and to augm nt our understa ding of the distribution and ecology of this rare species in the Mediterranean Sea. MA ERIAL AND ME HODS Records of white shark C. carcharias off the Libyan coast were accumulated within the context of the citizen-science initiative “Monitoring Elasmobranchii in Libyan Waters”, which was conduct d by “Marine Biology n Libya”. This programme puts a focu on the occurrence of chondrichthyan fishes in the Mediterranean Sea and applies a verified citizen science model, in which citizen-submitted observations are checked by experts (Gardiner et al., 2012). The records either came directly from fishermen reporting their catch, or through systematic online searches on social media platforms, namely Facebook, YouTube, Instagram, and Twitter using the Arabic keyword for great white shar , قرش) alqarsh al'abyad”) and shark“ , القرش األبیض “qarash”; or حركلب ب , “kaleb baher”). Following the ethical code proposed by Monkman et al. (2018), all web scraping w s performed responsibly to avoid compromising any personal data or images. All records had to be accompanied by photographic evidence confirming the , “alqarsh al’abyad”) and shark ( species in the Mediterranean Sea (e.g., Giovos et al., 2019; Kabasakal & Bilecenoğlu, 2020; Jambura et al., 2021). Landing almost 4.3 tonnes of chondrichthyan fishes in 2015, Libya is the leading country for chondrichthyan catches in the Mediterranean Sea (Jeffries, 2019). However, little is known about the presence of white sharks in Libyan waters and only one single record of a large female white shark off the Libyan coast does xist (Galaz & De M ddalena, 2004). Assessing the presence of white sharks in Libyan waters is, consequently, of utmost importance for future conservation planning of this iconic shark species. In our study, a systematic online search on popular social media platforms (i.e., Facebook, YouTube, Instagram, an Twitter) was conducted to document the presence of the great white shark C. carcharias along the Libyan coast and to augment our under t ing f the distribution and ecology of this rare species in the Mediterranean Sea. MATERIAL AND METHODS Records of white shark C. carcharias off the Libyan coast were accumulated within the context of the citizen-science initiative “Monitoring Elasmobranchii in Libyan Waters”, which was conducted by “Marine Biology i Libya”. This programme puts a focus on the occurrence of chondrichthyan fishes in the Mediterranean Sea and applies a verified citizen science model, in which citizen-submitted observations are checked by experts (Gardiner et al., 2012). The records either came directly from fishermen reporting their catch, or through systematic online searches on social media platforms, namely Facebook, YouTube, Instagram, and Twitter using the Arabic keyword for great w ite shark (القرش األبیض , “alqarsh al'abyad”) and shar , قرش) “qarash”; or حركلب ب , “kaleb baher”). Following the ethical code proposed by Monkman et al. (2018), all web scraping was performed responsibly to avoid compromising any personal data or images. All records had to be accompanied by photographic evidence confirming the , “qarash”; or species in the Mediterranean Sea (e.g., Giovos et al., 2019; Kabasakal & Bilecenoğlu, 2020; Jambura et al., 2021). Landing almost 4.3 tonnes of chondrichthyan fishes in 2015, Libya is the leading country for chondrichthyan catches in the Mediterranean Sea (Jeffries, 2019). However, little is known about the presence of white sharks in Libyan waters and only one single record of a large female white shark off the Libyan coast does exist (Galaz & De Maddalena, 2004). Assessing the presence of white sharks in Libyan waters is, consequently, of utmost importance for future conservation planning of this iconic shark species. In our study, a systematic online search on popular social media platforms (i.e., Facebook, YouTube, Instagram, and Twitter) was conducted to docume t the presence of the great white shark C. carcharias along the Libyan coast and to augment our understanding of the distribution and ecology of this rare species in the Mediterrane n Sea. MATERIAL AND METHODS Records of white shark C. carcharias off the Libyan coast were accumulated within the context of the citizen-science initiative “Monitoring Elasmobranchii in Libyan Waters”, which was conducted by “Marine Biology in Libya”. This programme puts a focus on the occurrence of chondrichthyan fishes in the Mediterranean Sea and applies a verified citizen science model, in which citizen-submitted observations are checked by experts (Gardiner et al., 2012). The records either came directly from fi hermen reporting their catch, or through systematic online searches on social media platforms, namely Facebook, YouTube, Instagram, and Twitter using the Arabic keyword for great white shark (القرش األبیض , “alqarsh al'abyad”) and shark (قرش , “ aras ”; r حركلب ب , “kaleb baher”). Following the ethical code proposed by Monkman et al. (2018), all web scraping was performed responsibly to avoid compromising any personal data or images. All records had to be accompanied by photographic evidence confirming the , “kaleb baher”). Following the ethical code proposed by Monkman et al. (2018), all web scraping was performed re- sponsibly to avoid compromising any personal data or images. All records had to be accompanied by ph tographic evidenc confirming the identification of the reported species. Authenticity and originality of the images were checked with the Google auto- matic image recognition tool. Species identification was based on the following features: (1) heavily, long-snouted spindle-shaped body; (2) strong keels on caudal peduncle; (3) large first dorsal fin, very small second dorsal and anal fins; (4) lunate caudal fin; (5) large, flat, triangular, serrated teeth; (6) long ANNALES · Ser. hist. nat. · 31 · 2021 · 1 53 Patrick L. JAMBURA et al.: USING CITIZEN SCIENCE TO DETECT RARE AND ENDANGERED SPECIES: NEW RECORDS OF THE GREAT WHITE SHARK ..., 51–60 gill slits; (7) black eyes; (8) sharp colour change from greyish dorsally to white ventrally; (9) pectoral fins with black tips on the ventral side (Ebert et al., 2013). Subsequent interviews were conducted with citizen scientists to confirm the reported data and obtain further information. If direct contact with the observer was not successful, the record was consid- ered ambiguous and subsequently discarded. In ad- dition to date and location, the following data were added to each record when possible: (1) time, (2) fishing method, (3) condition, (4) sex, (5) estimated total length (TLest), (6) weight (Tab. 1). Estimated total lengths were validated by comparing the shark with objects of known size in the photos. When appli- cable, ontogenetic stages were identified based on the total length following Boldrocchi et al. (2017): young of the year (YOY) (TL ≤ 1.75 m), juvenile (TL 1.75–3.0 m), subadult (♂TL 3.0–3.6 m; ♀TL 3.0–4.5 m), adult (♂TL > 3.6 m; ♀TL > 4.5 m). RESULTS Between 2017 and 2020, six white sharks (C. carcharias) were reported off the Libyan coast, constituting 42.9% of all published records of this species in the entire Mediterranean Sea during the same period (Tab. 1). One record was from 2017, one from 2018, and four were from 2020. Half of the recorded white sharks were reported dead (n=3); two of them were caught in set gillnets and one was washed ashore (see cases 2, 3, and 5). Ontogenetic stage and sex could be determined for four and three individuals, respectively; two sharks were adults (one male, one of unknown sex) and two were juveniles (both female). A short description for each record is provided below. Case 1: On 29 July 2017, a white shark was filmed from an oil platform while swimming near the surface in the Bouri Offshore Field, 120 km north of Country Region Date Fishing type Condition Sex Ontogeny TL [cm] Weight [kg] Coordinates Source Italy Lampedusa 23.05.2020 observation alive female adult 500 - - Tiralongo et al. (2020) Libya Bouri field 29.07.2017 observation alive - adult* 600* - 34.054444°N, 12.789972°E this study Buerat 16.05.2018 gillnet dead female juvenile 230 135 31.399611°N, 15.736333°E this study Brega 12.01.2020 observation dead male adult 520 - 30.3475°N, 19.441528°E this study Daryanah 23.04.2020 observation alive - adult* 600* - 32.398306°N, 20.339444°E this study Tripoli 21.09.2020 gillnet dead female YOY 140 - - this study Tripoli 04.11.2020 observation alive - adult* 600* - 32.959333°N, 13.167389°E this study Turkey Gökçeada 01.2017 gillnet dead - juvenile 180 - - Kabasakal (2020a) Altınoluk 04.2017 gillnet alive - YOY 160 - - Kabasakal (2020a) Didim 04.06.2017 purse seine dead male juvenile 200 60 - Kabasakal et al. (2019) Izmir 14.04.2018 gillnet dead female juvenile 180 - - Kabasakal et al. (2019) Sousse 28.04.2020 drift longline dead female juvenile 232 90 35.016944°N, 12.186389°E Ben-Amor et al. (2020) Kumkale 08.06.2020 gillnet dead - YOY 155 - - Kabasakal (2020b) Enez 14.06.2020 observation alive - juvenile 200 - - Kabasakal (2020b) Tab. 1: Observations of great white sharks (Carcharodon carcharias) reported from the Mediterranean Sea between 2017 and 2020. Abbreviation: YOY, young-of-year. *size and ontogenetic stage estimated by the observer. Tab. 1: Opazovanja belih morskih volkov (Carcharodon carcharias), ki so bila v Sredozemskem morju doku- mentirana v letih 2017-2020. Okrajšava: YOY, enoletni primerek. *velikost in ontogenetski stadij, ki ga je ocenil opazovalec. ANNALES · Ser. hist. nat. · 31 · 2021 · 1 54 Patrick L. JAMBURA et al.: USING CITIZEN SCIENCE TO DETECT RARE AND ENDANGERED SPECIES: NEW RECORDS OF THE GREAT WHITE SHARK ..., 51–60 Fig. 1: Occurrence of the great white shark (Carcharodon carcharias) off the Libyan coast. Recent records (circle) were reported between 2017 and 2020, while the only previously published record (triangle) was reported in 2002. Detailed information about each observation is provided in Table 1. Sl. 1: Pojavljanje belega morskega volka (Carcharodon carcharias) vzdolž libijske obale. Recentni podat- ki (krogci) izvirajo med leti 2017 in 2020, medtem ko je bil edini dokumentirani zapis o pojavljanju te vrste (trikotnik) objavljen leta 2002. Natančni podatki o vsakem od opazovanih primerov so navedeni v Tabeli 1. the Libyan coast, (34.054444°N, 12.789972°E; Figs. 1, 2A; Tab. 1). It was not possible to determine the sex or size of this specimen. The observer, however, estimated it to be 6 m long, and, therefore, likely an adult specimen. Case 2: On 16 May 2018, a small white shark was caught in a gillnet near the village of Buerat, 84 km west of Sirte (31.399611°N, 15.736333°E; Figs. 1, 2B; Tab. 1). The shark was alive when captured, but was landed and sold at the local fish market. The fishermen identified it as a shortfin mako shark (Isurus oxyrinchus), however, the black tips on the ventral side of the pectoral fins and the flat triangular teeth clearly indicate it was a white shark. The speci- men was a female measuring 2.3 m (total length, TL) and, therefore, a juvenile. Case 3: On 12 January 2020, a large white shark was washed ashore near the town of Brega, 300 km east of Sirte (30.3475°N, 19.441528°E; Figs. 1, 2C; Tab. 1). No external injuries that would explain the cause of death could be detected. The specimen was a male with well developed claspers and measuring 5.2 m (TL). We, therefore, conclude that this speci- men represented an adult individual. Case 4: On 23 April 2020, a white shark was observed swimming near the surface following a small fishing vessel, which carried out blast fishing near the town of Daryanah, 32 km east of Benghazi ANNALES · Ser. hist. nat. · 31 · 2021 · 1 55 Patrick L. JAMBURA et al.: USING CITIZEN SCIENCE TO DETECT RARE AND ENDANGERED SPECIES: NEW RECORDS OF THE GREAT WHITE SHARK ..., 51–60 (32.398306°N, 20.339444°E; Fig. 1; Tab. 1). The fishermen estimated the shark to be 6 m long. The video material, however, did not allow confirmation of this estimate. Although the shark was reported to be alive, at the end of the video sequence one of the fishermen threw dynamite towards the shark in order to chase it off and probably killed it. Case 5: On 21 September 2020, a small white shark was caught in a set gillnet and landed in the Bab Albaher fish market in Tripoli (Figs 1, 2D; Tab. 1). The exact locality where this individual was caught could not be reconstructed. However, due to the ongoing civil war in Libya, fishing boats from Tripoli are not allowed to enter the Gulf of Sidra and are restricted to the area between the Libyan-Tunisian boundary to the west and the city of Misrata to the east. Therefore, it is certain that this individual was caught in the area around Tripoli. The shark was a female measuring 1.4 m. The presence or absence of an umbilical scar could not be verified because the whole ventral side of the shark was cut open. Nevertheless, the total length is well within the size category of young of year (YOY < 1.75 m) and, therefore, it is considered as such here. This record represents the southernmost occurrence of a YOY white shark in the Mediterranean Sea. Case 6: On 4 November 2020, a white shark was observed in the proximity of two small fishing vessels near Tripoli (32.959333°N, 13.167389°E; Figs. 1, 2E; Tab. 1). The shark was swimming close to the surface and was accompanied by seven pilot fish (Naucrates ductor). The total length was estimated to be 6 m by the fishermen, but the video sequence did not allow confirmation of this estimate or identification of the sex of the specimen. DISCUSSION The presence of white sharks in the Mediter- ranean Sea has been known since the Middle Ages (476–1453) but is documented solely based on anecdotal reports of rather rare encounters (De Maddalena & Heim, 2012; Boldrocchi et al., 2017). In the present paper, citizen science-sourced data from social media platforms was used to gain a more detailed insight into the occurrence, distribution, and ecology of this elusive species along the Libyan coast. The species was previously only reported from this region in a single record of an adult female shark caught in a tuna cage 55 miles off Tripoli (Galaz & De Maddalena, 2004). Our search resulted in six additional records reported over a relatively short period (between 2017 and 2020), indicating that this species might be more common in this area than previously thought. In a recent study, five specimens of C. carcharias were reported from the North East Aegean Sea, based on social media and internet sources (Kabasakal & Bilecenoğlu, 2020), further indicating the importance and potential of such data sources (and citizen science in general) for white shark research in the Mediterranean Sea. Our results suggest that both immature and mature white sharks exploit the waters off the Libyan coast. The Central Mediterranean Sea is characterised by high biodiversity, especially in the area around the Strait of Sicily (Spanò & De Domenico, 2017), which is also an area displaying a high occurrence of white sharks (Fergusson, 1996; Boldrocchi et al., 2017). Fergusson (1996) proposed that this region was criti- cal for the species’ reproduction and that the neritic waters of Sicily and Tunisia served as nursery areas, a hypothesis that has been supported by subsequent studies (e.g., Saïdi et al., 2005; Bradaï & Saïdi, 2013; Boldrocchi et al., 2017). Our observations of a young of the year and a juvenile white shark along the Libyan coast rep- resent the southernmost occurrence of immature individuals of this species in the Mediterranean Sea and suggest that the Central Mediterranean nursery area might not be restricted to Sicily and Tunisia but may extend as far south as Libya. This seems reasonable, as white sharks can inhabit vast nursery grounds with YOYs travelling up to 700 km within a month (Weng et al., 2007). The Gulf of Gabes, a frequently suggested nursery ground for white sharks (Saïdi et al., 2005; Bradaï & Saïdi, 2013), is situated ca. 350 km west of where the YOY reported here was landed. It should be noted that incidental captures of YOY and juvenile white sharks in Tunisia usually occur in winter and spring, with a peak in February, while no YOY or juvenile has been reported in September so far, when the specimen documented here was caught. Therefore, an eastwards movement of YOY and juvenile white sharks from their primary nursery area in the Gulf of Gabes cannot be excluded either. The juvenile specimen reported here was caught further east, ca. 700 km west of the Gulf of Gabes. Previously, juveniles were reported to travel greater distances than YOYs (Kabasakal, 2020a), further indicating that the Libyan coast might serve as an extension of the nursery ground of the Gulf of Gabes. More data, however, is needed to confirm this. The great white shark C. carcharias is listed as an Appendix II species of the Convention on Inter- national Trade in Endangered Species (CITES) and is also included in the Barcelona Convention Annex II SPA/BD protocol. According to the Fisheries Commis- sion for the Mediterranean Sea (GFCM), white sharks caught during fishing operations have to be released promptly and unharmed to the greatest extent pos- sible. They cannot be retained on board, transferred, landed or sold (Recommendation GFCM/42/2018/2). Our study revealed that critically endangered white ANNALES · Ser. hist. nat. · 31 · 2021 · 1 56 Patrick L. JAMBURA et al.: USING CITIZEN SCIENCE TO DETECT RARE AND ENDANGERED SPECIES: NEW RECORDS OF THE GREAT WHITE SHARK ..., 51–60 Fig. 2: Reports of great white sharks (Carcharodon carcharias) observed off the Libyan coast between 2017 and 2020. Detailed information about each observation is provided in Table 1. Photo credits: (A) Jamal Al hamali, (B) Archive Marine Biology in Libya Society, (C) Mohamed Ahmed Salah, (D) Kamal Zager, (E) Aimen Al jerbie. Sl. 2: Pojavljanje morskega volka (Carcharodon carcharias) vzdolž libijske obale v obdobju med 2017 in 2020. Natančni podatki o vsakem od opazovanih primerov so navedeni v Tabeli 1. Avtorji fotografij: (A) Jamal Al hamali, (B) Archive Marine Biology in Libya Society, (C) Mohamed Ahmed Salah, (D) Kamal Zager, (E) Aimen Al jerbie. ANNALES · Ser. hist. nat. · 31 · 2021 · 1 57 Patrick L. JAMBURA et al.: USING CITIZEN SCIENCE TO DETECT RARE AND ENDANGERED SPECIES: NEW RECORDS OF THE GREAT WHITE SHARK ..., 51–60 sharks are caught and sold in Libya, despite Libya be- ing a member of the GFCM and, therefore, obliged to follow this recommendation. One of the main prob- lems we identified when talking to fishermen about their records was that they were completely unaware of the presence of white sharks in their fishing area and usually mistook the reported specimens for shortfin makos (Isurus oxyrinchus). We therefore urge for the organisation of educational and awareness campaigns aimed at aiding fishermen in correctly identifying white sharks and informing them about the white shark’s conservation status and regulations that are in place to help this species recover in the Mediterranean Sea. ACKNOWLEDGEMENTS This study was carried out as part of the citizen science collaboration “The MECO (Mediterranean Elasmobranch Citizen Observations) Project”. We further want to thank Ali Embarak, Daw Haddoud, Moutaz Mohamed Ehshad, Aymen Al-jerbie, and a reporter who wants to stay anonymous for provid- ing additional photographs and information about the records. We are very grateful to two anonymous reviewers for their comments on a previous version of this manuscript. This research was supported by the Austrian Science Fund (FWF): P 33820 to Jürgen Kriwet. ANNALES · Ser. hist. nat. · 31 · 2021 · 1 58 Patrick L. JAMBURA et al.: USING CITIZEN SCIENCE TO DETECT RARE AND ENDANGERED SPECIES: NEW RECORDS OF THE GREAT WHITE SHARK ..., 51–60 UPORABA LJUBITELJSKE ZNANOSTI ZA PRIDOBIVANJE PODATKOV O REDKI IN OGROŽENI VRSTI: NOVI PODATKI O POJAVLJANJU BELEGA MORSKEGA VOLKA CARCHARODON CARCHARIAS OB LIBIJSKI OBALI Patrick L. JAMBURA & Julia TÜRTSCHER University of Vienna, Department of Palaeontology, Vienna 1090, Austria e-mail: patrick.jambura@gmail.com Alessandro DE MADDALENA Shark Museum, Cape Town 7995, South Africa Ioannis GIOVOS iSea, Environmental Organization for the Preservation of the Aquatic Ecosystems, Thessaloniki 54645, Greece Jürgen KRIWET University of Vienna, Department of Palaeontology, Vienna 1090, Austria Jamila RIZGALLA University of Tripoli, Faculty of Agriculture, Department of Aquaculture, Tripoli, Libya Sara A. A. AL MABRUK Higher institute of Science and Technology, Department of General Nursing Technology, Cyrene, Libya Marine Biology in Libya Society, El Bayda, Libya POVZETEK Čeprav je navzočnost belega morskega volka (Carcharodon carcharias) v Sredozemskem morju dobro raziskana, so srečanja s to vrsto redka, domneve o njeni prostorski in časovni razširjenosti pa temeljijo predvsem na anekdo- tičnih opazovanjih. Do zdaj je bil objavljen le en zapis o pojavljanju ob libijski obali, zaradi katerega ni jasno ali je pojavljanje te vrste podcenjeno ali pa gre za redko in slučajno vrsto. V tem prispevku so avtorji želeli z uporabo podatkov na osnovi ljubiteljske znanosti dokumentirati navzočnost belega morskega volka ob libijski obali. Zbrali so 6 dodatnih primerov pojavljanja te vrste med leti 2017 in 2020, ki se nanašajo na komaj skotene mladiče ter mladostne in odrasle primerke. V prispevku poudarjamo potrebo po raziskovalnem monitoringu te vrste vzdolž libijske obale, ki bi olajšala pripravo učinkovitih varstvenih načrtov za varovanje te kritično ogrožene vrste. Ključne besede: Elasmobranchii, hrustančnice, ohranitvena biologija, ribištvo, družbena omrežja, ogrožena vrsta ANNALES · Ser. hist. nat. · 31 · 2021 · 1 59 Patrick L. JAMBURA et al.: USING CITIZEN SCIENCE TO DETECT RARE AND ENDANGERED SPECIES: NEW RECORDS OF THE GREAT WHITE SHARK ..., 51–60 REFERENCES Boldrocchi, G., J. Kiszka, S. 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ANNALES · Ser. hist. nat. · 30 · 2020 · 1 61 Saul CIRIACO et al.: A RECORD OF RARE SPINY BUTTERFLY RAY, GYMNURA ALTAVELA (LINNAEUS, 1758), IN THE AMVRAKIKOS GULF (GREECE), 39–42 IHTIOLOGIJA ITTIOLOGIA ICHTHYOLOGY ANNALES · Ser. hist. nat. · 30 · 2020 · 1 62 Saul CIRIACO et al.: A RECORD OF RARE SPINY BUTTERFLY RAY, GYMNURA ALTAVELA (LINNAEUS, 1758), IN THE AMVRAKIKOS GULF (GREECE), 39–42 ANNALES · Ser. hist. nat. · 31 · 2021 · 1 63 received: 2021-03-24 DOI 10.19233/ASHN.2021.09 A NEW RECORD OF CLINITRACHUS ARGENTATUS (OSTEICHTHYES: CLINIDAE) FROM THE TUNISIAN COAST (CENTRAL MEDITERRANEAN SEA) Sihem RAFRAFI-NOUIRA Université de Carthage, Unité de Recherches Exploitation des Milieux aquatiques, Institut Supérieur de Pêche et d’Aquaculture de Bizerte, BP 15, 7080 Menzel Jemil, Tunisia Christian REYNAUD Laboratoire Interdisciplinaire en Didactique, Education et Formation, Université de Montpellier, 2 place Marcel Godechot, B.P. 4152, 34092 Montpellier cedex 5, France Christian CAPAPÉ Laboratoire d’Ichtyologie, Université de Montpellier, case 104, 34095 Montpellier cedex 5, France e-mail: capape@univ-montp2.fr ABSTRACT The present note reports a new record of Clinitrachus argentatus (Risso, 1810) from Tunisian waters based on a specimen found in the stomach contents of a black scorpion fish Scorpaena porcus Linnaeus, 1758. The cline was only slightly digested, proving that the prey and the predator occurred in the same area. This finding extends the range of the species off the Tunisian coast, which was previously only reported from southern areas. Key words: Clinitrachus argentatus, prey, predator, stomach content, Scorpaena porcus NUOVO RITROVAMENTO DI CLINITRACHUS ARGENTATUS (OSTEICHTHYES: CLINIDAE) AL LARGO DELLA COSTA TUNISINA (MEDITERRANEO CENTRALE) SINTESI La presente nota riporta un nuovo ritrovamento di Clinitrachus argentatus (Risso, 1810) nelle acque tunisine, basato su un esemplare trovato nel contenuto stomacale di uno scorfano nero Scorpaena porcus Linnaeus, 1758. La bavosella d’alga era solo leggermente digerita, dimostrando che la preda e il predatore si trovavano nella stessa zona. Questa scoperta estende l’areale della specie al largo della costa tunisina, mentre in precedenza era stata segnalata solo da aree meridionali. Parole chiave: Clinitrachus argentatus, preda, predatore, contenuto dello stomaco, Scorpaena porcus ANNALES · Ser. hist. nat. · 31 · 2021 · 1 64 Sihem RAFRAFI-NOUIRA et al.: A NEW RECORD OF CLINITRACHUS ARGENTATUS (OSTEICHTHYES: CLINIDAE) FROM THE TUNISIAN ..., 63–68 INTRODUCTION Clinitrachus argentatus (Risso, 1810) commonly occurs in shallow coastal waters of the north-eastern Atlantic from Portugal (Carneiro et al., 2014) to Morocco (Lloris & Rucabado, 1998). The species is known throughout the western Mediterranean Basin, the Adriatic Sea, the Sea of Marmara, and the Bos- phorus Strait (Wirtz & Zander, 1986), its eastward distribution reaching the Levant Basin (Golani, 2005; Ali, 2108; Bariche & Fricke, 2019). While southwards, C. argentatus is not reported from the coast of Egypt (El Sayed et al., 2017), it does occur along the Libyan shore (El Baraasi et al., 2019). In Tunisia, C. argentatus was first recorded off Salakta, a city located on the eastern part of the coast, where Gharred (1999) observed 21 speci- mens, measuring between 29 and 76 mm in total length. Since then no additional of C. argentatus had been recorded in the wild although several studies focussing on the local ichthyofauna were performed (Bradaï et al., 2004; El Kamel-Moutalibi et al., 2009; Ounifi-Ben Amor et al., 2016; Rafrafi- Nouira, 2016). The present is a report of a new C. argentatus found in the stomach contents of a black scorpion fish Scorpaena porcus Linnaeus, 1758 during a study on the diet of this species (Rafrafi-Nouira et al., 2016). MATERIAL AND METHODS The specimen of C. argentatus was found in the stomach contents of a black scorpionfish, Scor- paena porcus Linnaeus, 1758 caught on 21 October 2013 in a commercial gill net with a mesh size of 26 mm, off Ras Jebel, northern Tunisia, on rocky bottom partially covered by sea grass and algae, at 37°14’331.84”N and 10°09’52.35”E (Fig. 1). The scorpionfish was an adult male measuring 188 mm in total length (TL) and its total body weight (TBW) reached 142 g. The specimen of C. argentatus meas- ured 48 mm TL and weighed at least 3.1 g (Fig. 2). The digestion slightly affected the distal end of its caudal fin and areas of its anal fin. Some measure- ments and meristic counts were recorded and sum- marised in Table 1. The specimen was fixed in 10% buffered formaline and preserved in 75% ethanol. It was deposited in the Ichthyological Collection of Institut Supérieur de Pêche et d’Aquaculture of Bizerte, located in Menzel Jemil (Tunisia), under catalogue number ISPAB Cli-arg 01. RESULTS AND DISCUSSION Although it was slightly affected by the begin- ning of digestion in the stomach of S. porcus, the present specimen was identified as C. argentatus through the combination of the following mor- phological characters: body flattened laterally, covered with cycloid scales deeply embedded in skin; caudal peduncle thin; head conical and more pointed than in specimens from the Blenniidae family according to Wirst & Zander (1986); dorsal fin with deep incision, anterior part consisting of three spines, posterior part high, especially in its distal area, the meristic formula of dorsal fin simi- lar to that recorded by Orlando-Bonaca & Trkov (2016). The colour of the specimen was orange- reddish with yellow areas, which was rather unu- sual compared to Orlando-Bonaca & Trkov (2016), who noted that the species is dark green or brown- ish with a marbled pattern, displaying some white or silver areas. Additionally, Orlando-Bonaca & Trkov (2016) added that the colour pattern of the species varies according to the macroalgal species used by C. argentatus as a hiding place, and can Fig. 1: Map of Tunisia indicating the capture sites of Clinitrachus argentatus in the Tunisian coast. 1. Off Salakta, eastern Tunisia (Gharred, 1999; Bradaï, 2000). 2. Off Ras Jebel, northern Tunisia (this study). GT, Gulf of Tunis. GH, Gulf of Hammamet. GG, Gulf of Gabès. Sl. 1: Zemljevid Tunizije z označenimi lokalitetami, kjer je bila potrjena srebrnica (Clinitrachus argenta- tus) na tunizijski obali. 1. Salakta, vzhodna Tunizija (Gharred, 1999; Bradaï, 2000). 2. Ras Jebel, Severna Tunizija (ta študija). GT, Tuniški zaliv. GH, Hamame- ški zaliv. GG, Gabeški zaliv. ANNALES · Ser. hist. nat. · 31 · 2021 · 1 65 Sihem RAFRAFI-NOUIRA et al.: A NEW RECORD OF CLINITRACHUS ARGENTATUS (OSTEICHTHYES: CLINIDAE) FROM THE TUNISIAN ..., 63–68 be brown, reddish, or purplish. The unusual colour of the present specimen could be explained by the chemical secretions of the predator affecting the prey’s skin during the early phase of digestion. The description, morphometric measurements, and meristic counts recorded in the present speci- men were in total accordance with Wirtz & Zander (1986) and Orlando-Bonaca & Trkov (2016). There- fore, these patterns confirm the occurrence of C. argentatus in Tunisian waters and extend the distri- bution range of the species in the area. However, a migration of the species from southern to northern areas remains doubtful and improbable, as the species is not prone to long-distance migrations. Additionally, the presence of an only slightly di- gested C. argentatus in the gut of a S. porcus clearly demonstrated that the prey and the predator inhabit the same area. The non-occurrence of C. argentatus between Ras Jebel (northern Tunisia) and Salakata (eastern Tunisia) does not indicate that the species’ distribution is fragmented throughout the Tunisian coast. C. argentatus is a rather overlooked species due to poor sampling efforts; similar instances were reported for other fish species in Tunisian waters (Rafrafi-Nouira, 2016). Similarly, the relative scarcity of C. argentatus throughout the wider Mediterranean Sea is prob- ably due to the fact that it is a cryptic species inhabiting macroalgal assemblages and sea grass meadows at very low depths, where it is difficult to observe (Orlando-Bonaca & Trkov, 2016; Tira- longo et al., 2016). Additionally, such biotopes are poorly exploited by commercial fishing gears and colonised by small fish species generally belonging to the gobiidae and blenniidae families (Tiralongo Fig. 2: Clinitrachus argentatus from the northern Tunisian coast (ref. ISPAB-Cli-arg 01), specimen found in the stomach contents of a black scorpion fish Scorpaena porcus, scale bar = 20 mm. Sl. 2: Primerek srebrnice (Clinitrachus argentatus) (ref. ISPAB-Cli-arg 01), najden v želodcu rjavega škarpoča (Scorpaena porcus), ujetega na severni tunizijski obali. Merilo = 20 mm. Tab. 1: Morphometric measurements with percentages of standard length (% SL), meristic counts, and total weight recorded in Clinitrachus argentatus from the northern Tunisian coast (ref. ISPAB-Cli-arg 01), speci- men found in the stomach contents of a black scorpion fish Scorpaena porcus. Tab. 1: Morfometrične meritve z deleži standardne dolžine (% SL), meristična štetja in celokupna masa srebrnice (Clinitrachus argentatus) iz severne tunizij- ske obale (ref. ISPAB-Cli-arg 01), najdene v vsebini želodca rjavega škarpoča (Scorpaena porcus). Ref. ISPAB-Cli-arg 01 Value Morphometric measurements mm % SL Total length 48 129.7% Standard length (SL) 37 100% Head length 7 18.9% Eye diameter 3 8.1% Pre-orbital length 4 10.8% Meristic counts Dorsal fin rays III + XXVIII/3 Anal fin rays ? Pectoral fin rays 9 Pelvic fin rays 2 Total weight in gram 3.2 (?) ANNALES · Ser. hist. nat. · 31 · 2021 · 1 66 Sihem RAFRAFI-NOUIRA et al.: A NEW RECORD OF CLINITRACHUS ARGENTATUS (OSTEICHTHYES: CLINIDAE) FROM THE TUNISIAN ..., 63–68 et al., 2016). Therefore, misidentification between close related species cannot be totally ruled out. All these species are of low commercial interest and discarded at sea or not delivered in fish mar- kets, but kept by fishermen for their own consump- tion. They are also affected by predation pressure for food, a good instance is herein provided by C. argentatus; Tiralongo et al. (2016) noted the oc- currence of scorpaenid species such as S. scrofa Linnaeus, 1758 and S. maderensis Valenciennes, 1833, living together with small fishes, which are also their preferential prey (Hureau & Litvinenko, 1986). Additionally, shallow coastal waters are facing anthropogenic pollution, which progres- sively reduces benthic vegetation and negatively affects fish biodiversity (Lipej et al., 2003) and likely certain small species that inhabit these eco- systems, such as C. argentatus (Orlando-Bonaca & Trkov, 2016), as well. ACKNOWLEDGEMENTS The authors wish to thank Mr Al Arbi Ibn Habib Nouira and his wife, Mrs Asyia Ibnat Marhaz Nouira, fishermen from Ras Jebel, who kindly provided us several Scorpaena porcus and among them the speci- men which ingested Clinitrachus argentatus. They are also grateful to two anonymous referees for helpful and useful comments allowing to enlarge and improve the scientific quality of the manuscript. ANNALES · Ser. hist. nat. · 31 · 2021 · 1 67 Sihem RAFRAFI-NOUIRA et al.: A NEW RECORD OF CLINITRACHUS ARGENTATUS (OSTEICHTHYES: CLINIDAE) FROM THE TUNISIAN ..., 63–68 NOVI ZAPIS O POJAVLJANJU SREBRNICE CLINITRACHUS ARGENTATUS (OSTEICHTHYES: CLINIDAE) IZ TUNIZIJSKE OBALE (OSREDNJE SREDOZEMSKO MORJE) Sihem RAFRAFI-NOUIRA Université de Carthage, Unité de Recherches Exploitation des Milieux aquatiques, Institut Supérieur de Pêche et d’Aquaculture de Bizerte, BP 15, 7080 Menzel Jemil, Tunisia Christian REYNAUD Laboratoire Interdisciplinaire en Didactique, Education et Formation, Université de Montpellier, 2 place Marcel Godechot, B.P. 4152, 34092 Montpellier cedex 5, France Christian CAPAPÉ Laboratoire d’Ichtyologie, Université de Montpellier, case 104, 34095 Montpellier cedex 5, France e-mail: capape@univ-montp2.fr POVZETEK V pričujočem zapisu avtorji poročajo o novi najdbi srebrnice Clinitrachus argentatus (Risso, 1810) iz tunizijskih voda na podlagi primerka, najdenega v želodcu rjavega škarpoča Scorpaena porcus Linnaeus, 1758. 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Paladini De Mendoza, C. Melchiorri & M. Marcelli (2016): Habitat preference of combtooth blennies (Actinopterygii: Perciformes: Blenniidae) in very shallow waters of the Ionian Sea, south-eastern Sicily, Italy. Acta Ichthyol. Piscat., 46(2), 67-75. Wurst, P. & C.D. Zander (1986): Clinidae. In: P.J.P. Whitehead, M.L. Bauchot, J.C. Hureau., J. Nielsen J.& Tortonese. E. (Editors), p. 1117. Fishes of the North- western Atlantic and the Mediterranean, Vol III, UN- ESCO, Paris. ANNALES · Ser. hist. nat. · 31 · 2021 · 1 69 received: 2021-01-07 DOI 10.19233/ASHN.2021.10 VARIAZIONI PLURIENNALI DEL FENOMENO DELLO SPIAGGIAMENTO DI SPECIE ITTICHE NELLO STRETTO DI MESSINA, CON PARTICOLARE ATTENZIONE ALLE SPECIE MESOPELAGICHE Mauro CAVALLARO Departement of Veterinary Sciences, University of Messina, Polo Universitario dell’Annunziata, 98168 Messina - Italy e-mail: mcavallaro@unime.it Giovanni AMMENDOLIA Via C. Pompea, 3 – 98168 Messina – Italy Ignazio RAO Viale Principe Umberto, 119 – 98122 Messina - Italy Alberto VILLARI Salita Villa Contino, 30 - 98124 Messina - Italy Pietro BATTAGLIA Stazione Zoologica Anton Dohrn, Department of Integrative Marine Ecology, SZN, 98168 Messina - Italy SINTESI I risultati di un anno solare di monitoraggio del fenomeno dello spiaggiamento di specie ittiche lungo la costa siciliana dello Stretto di Messina, hanno permesso di mettere a confronto i dati raccolti, sia quantitativi che qualitativi, con i risultati delle ricerche realizzate da autori del passato. Le osservazioni sono state condotte con cadenza giornaliera prescindendo dalle condizioni meteomarine, e astronomiche fondamentali nella regolazione di questo peculiare fenomeno. I dati, devono essere interpretati in maniera non assoluta poiché lo spiaggiamento è un fenomeno che assume caratteristiche di occasionalità ed è regolato da leggi probabilistiche. Dall’indagine è emersa una evidente variazione rispetto al passato, con una rilevante diminuzione di specie. Sono stati effettuati approfondimenti sulle 17 specie di pesci mesopelagici in comune con le ricerche degli autori del passato, in modo da avere un quadro sull’andamento di tali variazioni. Parole chiave: spiaggiamento, Stretto di Messina, specie mesopelagiche MULTI-YEAR CHANGES IN FISH STRANDING PHENOMENA IN THE STRAIT OF MESSINA, WITH PARTICULAR ATTENTION TO MESOPELAGIC SPECIES ABSTRACT This study provides data on one-year monitoring of the stranding phenomenon in the Strait of Messina, reporting information on the abundance and frequency of beached fish species. A comparison with previous studies performed in the area has allowed to describe the changes in this phenomenon over the course of a century. Key words: stranding phenomenon, Strait of Messina, mesopelagic species ANNALES · Ser. hist. nat. · 31 · 2021 · 1 70 Mauro CAVALLARO et al.: VARIAZIONI PLURIENNALI DEL FENOMENO DELLO SPIAGGIAMENTO DI SPECIE ITTICHE NELLO STRETTO DI MESSINA ... , 69–84 INTRODUZIONE Lo Stretto di Messina deve la sua notorietà alle forti cor- renti di marea i cui effetti sono conosciuti sin dall’antichità. Alle prime osservazioni scientifiche operate da Galileo nel “Dialogo sopra i due massimi sistemi” seguirono successiva- mente quelle di numerosi altri Autori come Ribaud (1824), Longo (1882), Platania (1905), Mazzarelli (1909), Marini (1910), sebbene il primo trattato di dinamica fisica fu scritto da Vercelli (1925) e approfondito successivamente insieme a Picotti (Vercelli & Picotti, 1926). Studi relativamente recenti hanno esaminato le tematiche inerenti l’andamento di tali correnti di marea (Defant, 1940; De Domenico, 1987; Mosetti, 1988; Cortese et al., 1990; Ammendolia et al., 2018). Uno degli aspetti più interessanti, legati ai fenomeni idrodinamici nello Stretto di Messina è lo spiaggiamento di numerose specie di organismi marini, che è un fenomeno naturale che si verifica in quest’area e consiste nel rinve- nimento di esemplari appartenenti a diversi phyla animali e vegetali sulla battigia (Mazzarelli, 1909; Genovese et al., 1971; Battaglia et al., 2017). La causa primaria è dovuta al regime idrodinamico molto intenso che si sviluppa in quest’area (Mazzarelli, 1909), determinato da correnti di ma- rea pulsanti, che ogni sei ore circa, tra i bacini del Mar Ionio e del Mar Tirreno, provocano il verificarsi di una inversione del flusso della corrente (Vercelli, 1925; Vercelli & Picotti, 1926). Uno degli effetti di questi fenomeni idrodinamici è la risalita di acque profonde provenienti dal bacino ionico fino alle acque superficiali. Tale risalita, anche grazie alla fisiografia dello Stretto, gioca un ruolo fondamentale nello spiaggiamento, poiché trasporta in pochissimo tempo la fauna profonda verso la superficie. Questo trasporto provoca negli organismi choc pressori, che spesso causano agonia e morte. In seguito il moto ondoso, la corrente e il vento ne determinano lo spiaggiamento sul litorale (Mazzarelli, 1909; Genovese et al., 1971; Battaglia et al., 2017). Sono diversi i fattori, oltre al regime idrodinamico e le correnti di marea, che possono favorire o influenzare il fenomeno dello spiaggiamento: direzione del vento, ciclo lunare, pressione atmosferica, stagionalità, pa- rametri ecologici e biologici (Battaglia et al., 2017). In particolare, per quanto concerne gli organismi mesope- lagici, l’abitudine a compiere migrazioni nictimerali può amplificare il fenomeno (Battaglia et al., 2017). Infatti, la migrazione verticale giornaliera del zooplancton nelle ore notturne verso la superficie (Marshall, 1960), innesca lo spostamento di moltissime specie mesopelagiche che per motivi trofici seguono le loro prede negli strati d’ac- qua superficiali. La risalita verso strati batimetrici meno profondi espone queste specie (molto spesso di piccole dimensioni) al rischio di essere “intercettate” dalla cor- rente di risalita (Battaglia et al., 2017). Le pionieristiche osservazioni del naturalista messinese Anastasio Cocco hanno permesso, per la prima volta in Mediterraneo, la descrizione tassonomica delle specie ittiche profonde rinvenute spiaggiate sulla costa siciliana dello Stretto di Messina (Ammendolia et al., 2014). Da allora, il feno- meno dello spiaggiamento ha richiamato l’attenzione di numerosi studiosi provenienti da tutta Europa, tra i quali spicca la figura di Auguste Krohn, che definì lo Stretto di Messina come “il paradiso degli zoologi”. Mazzarelli (1909) mise per la prima volta in relazione le peculiarità idrodinamiche dello Stretto con il fenomeno dello spiag- giamento di specie definite a quel tempo “abissali” e ciò, per la prima volta in Mediterraneo, consentì studi sugli stadi larvali, giovanili e sullo sviluppo di diverse specie Fig. 1: Area di campionamento di 2,3 km lungo la costa siciliana dello Stretto di Messina. Sl. 1: 2,3 km dolgo območje vzorčenja ob sicilijanski obali Mesinske ožine. ANNALES · Ser. hist. nat. · 31 · 2021 · 1 71 Mauro CAVALLARO et al.: VARIAZIONI PLURIENNALI DEL FENOMENO DELLO SPIAGGIAMENTO DI SPECIE ITTICHE NELLO STRETTO DI MESSINA ... , 69–84 Fig. 2: Specie mesopelagiche utilizzate per la comparazione tra i diversi censimenti considerati (scale bar: 1 cm) – 1) Argyropelecus hemi- gymnus; 2) Ceratoscopelus maderensis; 3) Chauliodus sloani; 4) Cyclothone braueri; 5) Diaphus holti; 6) Diaphus rafinesquei; 7) Electrona rissoi; 8) Gonostoma denudatum; 9) Hygophum benoiti; 10) Ichthyococcus ovatus; 11) Maurolicus muelleri; 12) Mictophum punctatum; 13) Microstoma microstoma; 14) Nansenia oblita; 15) Trachypterus trachypterus; 16) Vinciguerria attenuata; 17) Vinciguerria poweriae. Sl. 2: Mezopelaške vrste, uporabljene za primerjavo med različnimi obravnavanimi popisi (merilo: 1 cm) – 1) Argyropelecus hemigymnus; 2) Ceratoscopelus maderensis; 3) Chauliodus sloani; 4) Cyclothone braueri; 5) Diaphus holti; 6) Diaphus rafinesquei; 7) Electrona rissoi; 8) Gonostoma denudatum; 9) Hygophum benoiti; 10) Ichthyococcus ovatus; 11) Maurolicus muelleri; 12) Mictophum punctatum; 13) Microstoma microstoma; 14) Nansenia oblita; 15) Trachypterus trachypterus; 16) Vinciguerria attenuata; 17) Vinciguerria poweriae. ANNALES · Ser. hist. nat. · 31 · 2021 · 1 72 Mauro CAVALLARO et al.: VARIAZIONI PLURIENNALI DEL FENOMENO DELLO SPIAGGIAMENTO DI SPECIE ITTICHE NELLO STRETTO DI MESSINA ... , 69–84 ittiche, soprattutto mesopelagiche (Sanzo, 1912; 1913a; 1913b; 1914; 1915; 1918a; 1918b). Successivamente molti altri autori hanno investigato gli aspetti legati al fenomeno (Genovese et al., 1971; Berdar et al., 1977; 1983; 1988; Guglielmo et al., 1995, Battaglia et al., 2017). In tempi recenti, numerosi studiosi si sono inoltre interessati della biologia riproduttiva (Bonina & Contini, 1974; Donato et al., 1976), dell’ecologia trofica (Berdar et al., 1979a; Battaglia et al., 2014; Esposito et al., 2014; Battaglia et al., 2018), delle parassitosi (Berdar et al., 1979b; Spalletta et al., 1995; Gaglio et al., 2018;), delle analisi biometriche (Donato et al., 1976; 1977; Potoschi et al., 2000; 2003; Battaglia et al., 2010; 2015), della pre- senza di microplastiche nei contenuti stomacali (Romeo et al., 2016), della struttura e l’ultrastruttura degli organi luminosi (Cavallaro et al., 2004; 2015; 2019; 2020) e della bioluminescenza (Baguet & Marechal, 1976; Chri- stophe et al., 1979;; Baguet et al., 1980, 1995) presente in specie ittiche mesopelagiche spiaggiate. Scopo del presente lavoro è stato quello di operare una comparazione in termini di abbondanza numerica e frequenza di specie tra i censimenti del passato e quello qui descritto, focalizzando l’attenzione su alcune specie ittiche al fine di poter descrivere alcuni aspetti dell’evo- luzione nel tempo del fenomeno dello spiaggiamento lungo il litorale siciliano dello Stretto di Messina. MATERIALI E METODI La raccolta delle specie ittiche spiaggiate sull’arenile siciliano dello Stretto di Messina (Fig. 1) è stata effettuata con frequenza giornaliera durante le prime ore del mattino, lungo la fascia che si estende per alcuni metri dalla linea di battigia (Battaglia et al., 2017). Il campionamento è stato effettuato durante l’anno solare compreso tra il 1 giugno 2015 e il 31 maggio 2016 da tutti gli autori. Il materiale biologico raccolto è stato immediatamente trasportato in laboratorio ed esaminato per l’identificazione tassonomica, seguendo le chiavi di identificazione di Whi- tehead et al. (1984-1986), e per le successive analisi quan- titative. È stata effettuata una analisi qualitativa delle specie ittiche rinvenute, registrando anche il numero di esemplari ritrovati in ogni giornata di campionamento. Sono state calcolate le abbondanze complessive per ciascuna specie e famiglia nel periodo di ricerca e per ogni mese. Focalizzando l’attenzione sulle specie mesopelagiche, al fine di poter meglio esaminare l’andamento del fenomeno dello spiaggiamento nel tempo, sono stati considerati i cen- Fig. 3: Abbondanza percentuale dei teleostei spiaggiati sulla costa dello Stretto di Messina nel periodo 1.6.2015 – 31.5.2016, raggruppati per famiglie. Sl. 3: Številčnost (v odstotkih) kostnic, ki so v obdobju od 1.6.2015 do 31.5.2016 nasedle na obali Mesinske ožine, razvrščene po družinah. ANNALES · Ser. hist. nat. · 31 · 2021 · 1 73 Mauro CAVALLARO et al.: VARIAZIONI PLURIENNALI DEL FENOMENO DELLO SPIAGGIAMENTO DI SPECIE ITTICHE NELLO STRETTO DI MESSINA ... , 69–84 simenti del passato in cui venivano riportati per ogni specie dati esaurienti di abbondanze di tali organismi con cadenza mensile (Genovese et al., 1971, Berdar et al., 1977; 1988- 1989) e comparati col presente studio. Inoltre, per integrare i dati di presenza/assenza delle specie è stata anche consi- derata la ricerca di Mazzarelli (1909), cioè la prima a fornire un quadro sul fenomeno dello spiaggiamento, sebbene non siano in essa riportati dati di abbondanze numeriche. Sulla base di quanto detto, sono state selezionate le 17 specie mesopelagiche (Fig. 2) che sono risultate presenti in tutti i censimenti oggetto del confronto. Sono stati comparati quindi valori di abbondanza delle specie, considerando anche i periodi (mesi) di spiaggiamento. Inoltre, per ciascuna specie, è stata calcolata la frequenza di spiaggiamento in termini percentuali di giorni/anno e in termini di presenza/assenza nei 12 mesi del periodo di campionamento. RISULTATI E DISCUSSIONE I risultati delle osservazioni e delle raccolte effettuate nell’arco dell’annualità presa in esame, sono riportati nel Supplemento 1. Sono state censite un totale di 78 specie di pesci, distribuite in 46 famiglie, per un numero complessivo di 3043 individui. Sono stati esclusi da questo conteggio gli 83 esemplari di larve leptocefaliche in quanto la loro corretta classificazione è ancora oggetto di studi tassonomici parallelamente condotti alla nostra indagine ed in corso di realizzazione. La specie più abbondante è risultata l’Ar- gyropelecus hemigymnus (n = 977), seguita da Hygophum hygomii (n=311) e Hygophum benoiti (n=315). In Figura 3 è riportato il grafico relativo all’abbondanza percentuale dei pesci spiaggiati, raggruppati per famiglia, nel periodo preso in esame. Si nota una netta prevalenza di esemplari appartenenti alle famiglie Sternoptychidae (32,6% del totale degli individui, rappresentati principalmente dalla specie A. hemigymnus) e Myctophidae (29%). Quest’ultima famiglia è quella più rappresentata in termini di specie rinve- nute, ben undici (11) a fronte di 32 famiglie censite con una singola specie. L’andamento dell’abbondanza dei ritrovamenti nei diversi periodi dell’anno è riportata in Figura 4. Il grafico mette in evidenza che gli intervalli temporali più favorevoli sono certamente quelli invernali - primaverili, dalla seconda metà del mese di febbraio fino al mese di maggio. In questi periodi si è infatti registrato un primo picco dei ritrovamenti. Un secondo picco, meno elevato rispetto al periodo prima- vera-inverno, è stato registrato nel mese di novembre. Fig. 4: Andamento dei ritrovamenti per mese e per famiglia di teleostei spiaggiati nel periodo di campionamento considerato (1.6.2015 – 31.5.2016). Sl. 4: Gibanje števila najdb po mesecih in družinah nasedlih kostnic v obravnavanem obdobju vzorčenja (1.6.2015-31.5.2016). ANNALES · Ser. hist. nat. · 31 · 2021 · 1 74 Mauro CAVALLARO et al.: VARIAZIONI PLURIENNALI DEL FENOMENO DELLO SPIAGGIAMENTO DI SPECIE ITTICHE NELLO STRETTO DI MESSINA ... , 69–84 I valori percentuali delle frequenze di spiaggiamento per le 17 specie mesopelagiche considerate, calcolate in termi- ni di n° mesi/anno e n° giorni/anno sono descritte nei grafici riportati in Figura 5. Le specie più frequenti sono risultate M. punctatum, A. hemigymnus e H. benoiti. In termini di frequenza mensile a queste si aggiungono anche E. risso e V. poweriae. I risultati della comparazione con i censimenti del pas- sato (Genovese et al., 1971; Berdar et al., 1977; 1988-1989) vengono riassunti nel Supplemento 2, in cui sono riportate rispettivamente le abbondanze di spiaggiamento negli anni 1971, 1977, 1987-88 e 2015-2016. Da questa valutazione è stata esclusa l’indagine di Maz- zarelli (1909) poiché l’autore non operò valutazioni quanti- tative sulle specie spiaggiate ma ne osservò esclusivamente la presenza nel corso del periodo del suo campionamento. Il lavoro di Mazzarelli è invece compreso nella valutazione dei periodi di spiaggiamento delle 17 specie considerate, in modo da valutare la presenza delle stesse nei mesi dell’anno (Suppl. 3). I periodi considerati abbracciano un arco tempo- rale di 107 anni e dalla loro analisi si evince che Mazzarelli (1909) rinviene la quasi totalità delle specie durante tutto l’arco dell’anno 1909 tranne cinque di esse che ritrova solo in determinati periodi. Si riporta a seguire la valutazione della comparazione effettuata per singola specie considerata. Argyropelecus hemigymnus Cocco, 1829 Tra le specie che spiaggiano lungo le coste dello Stretto di Messina, è tra quelle numericamente più significative, sia in termini di abbondanza che di frequenza. I nostri dati sul reperimento di questo teleosteo sono simili a quelli di Mazzarelli (1909), Genovese et al. (1971) e Berdar et al. (1977), mentre Berdar et al. (1988-1989) nel 1988-1989 non lo rinvengono nel mese di luglio. Anche Goode & Bean (1895), riportano che Giglioli reperì diverse centinaia di esemplari in soli tre giorni a causa delle forti correnti. Si può affermare che la specie spiaggia stabilmente tutto l’anno, nonostante flessioni in termini quantitativi nei periodi estivi. Ceratoscopelus maderensis Lowe, 1839 C. maderensis è piuttosto comune sia in Mediterraneo che in Atlantico in quanto tra le specie più numerose in termini di quantità di individui, a comporre lo strato riflet- tente profondo (Backus et al., 1968; Olivar et al., 2012). Mazzarelli (1909) lo ritrova spiaggiato nei mesi da gennaio a marzo mentre secondo Genovese et al. (1971) è presente su tutti i litorali indagati e per tutto l’anno. I nostri dati riportano esigui ritrovamenti limitati ai mesi di aprile e maggio. Anche i due censimenti operati da Berdar et al. (1977; 1988-1989) fanno registrare dati contrastanti, infatti, a fronte di grande abbondanza e frequenza durante il corso della prima inda- gine si riscontra forte diminuzione nella seconda. Chauliodus sloani, Bloch & Schneider, 1801 È una specie che si rinviene comunemente spiaggiata lungo tutti i litorali dello Stretto di Messina. Mazzarelli (1909) la segnala in tutti i mesi dell’anno mentre Genovese et al. (1971) la ritrovano da dicembre fino a primavera inoltrata, con numerosità di individui piuttosto elevate. Anche Berdar et al. (1977) registrano abbondanti ritrovamenti in tutti i mesi dell’anno, esclusi luglio e agosto, mentre nel 1988-1989 osservano la presenza di questa specie solo da gennaio a giugno. A testimonianza del fatto che il fenomeno dello spiaggiamento sia di non facile interpretazione e di come gli eventi atmosferici ed idrodinamici lo condizionino senza regole ben precise e stabilite. Durante il nostro censimento sono stati ritrovati solo due esemplari di C. sloani: uno a novembre ed uno a maggio. Cyclothone braueri Jespersen & Tâning, 1926 La specie è considerata come quella che annovera, tra tutti i vertebrati, la maggiore consistenza numerica delle sue popolazioni e quindi il reperimento della stessa si verifica con grandi quantità di biomassa che spesso sono costituite appunto da più specie congeneri (Palma, 1982). Mazzarelli (1909) non lo cita tra i teleostei spiaggiati come C. braueri, bensì come C. microdon, ed annovera questa specie come rinvenibile per tutto l’anno. Genovese et al. (1971) riportano ritrovamenti nei mesi di marzo e maggio con un picco a marzo. Berdar et al. (1977) rinvengono la specie quasi tutto l’anno, con l’eccezione dei mesi di agosto e settembre, mentre Berdar et al. (1988-1989) la rinvengono dal mese di gennaio fino a marzo. I nostri dati riportano una costanza di reperimento di C. braueri da febbraio a maggio con mode- rate frequenze numeriche, per un totale di 150 esemplari. Incrociando i dati, la frequenza della specie è pertanto da ritenersi stabile. Diaphus holti Tåning, 1918 Mazzarelli (1909) non la citò fra le specie soggette al fenomeno poiché è stata istituita da Tåning nel 1918, confondendola probabilmente con la specie affine D. rafine- squii. Genovese et al. (1971) ne registrano il reperimento da novembre a maggio ed in tutte le località da essi esplorate. Il censimento effettuato da Berdar et al. (1977) riporta dati interessanti poiché si registrano campioni reperiti quasi tutto l’anno, esclusi i mesi estivi. Tale dato non è però confermato dalla successiva indagine di Berdar et al. (1988-1989) che segnalano individui spiaggiati solo nei mesi di gennaio e febbraio. I nostri risultati sono simili a quelli di Genovese et al. (1971) con un leggero slittamento dell’inizio del periodo dei ritrovamenti (cinque esemplari tra dicembre e maggio). Alla luce di questi dati la reperibilità della specie è da consi- derarsi in lieve diminuzione. Diaphus rafinesquii Cocco, 1838 La specie non è molto comune. Discordanti sono i dati tra i censimenti di Mazzarelli (1909), quelli di Geno- vese et al. (1971) ed il nostro, infatti Mazzarelli (1909) la ritrova durante tutto l’anno, mentre Genovese et al. (1971) la rinvengono da gennaio a maggio. Berdar et al. (1977) riportano nel censimento del 1977 una notevole frequenza di ritrovamenti, mentre nella ricerca del 1988-1989 registra- ANNALES · Ser. hist. nat. · 31 · 2021 · 1 75 Mauro CAVALLARO et al.: VARIAZIONI PLURIENNALI DEL FENOMENO DELLO SPIAGGIAMENTO DI SPECIE ITTICHE NELLO STRETTO DI MESSINA ... , 69–84 Fig. 5: Valori di frequenza percentuale calcolata in numero di mesi/anno e numero di giorni/anno per le 17 specie mesopelagiche considerate. Sl. 5: Frekvenca v odstotkih, izračunana na podlagi števila mesecev/leto in števila dni/ leto za 17 obravnavanih mezopelaških vrst. ANNALES · Ser. hist. nat. · 31 · 2021 · 1 76 Mauro CAVALLARO et al.: VARIAZIONI PLURIENNALI DEL FENOMENO DELLO SPIAGGIAMENTO DI SPECIE ITTICHE NELLO STRETTO DI MESSINA ... , 69–84 rono ritrovamenti di pochi esemplari unicamente nei mesi di gennaio e febbraio (Berdar et al. 1988-1989). Il presente lavoro ha permesso di registrare il ritrovamento di un totale di 8 esemplari nell’arco di tempo compreso tra novembre ed aprile. D. rafinesquii sembra quindi aver subito una flessione di abbondanza e frequenza di reperimento. Electrona risso Cocco, 1829 Specie piuttosto comune, viene segnalata da Mazzarelli (1909), in località Faro (ME) durante tutti i mesi dell’anno, con un’abbondanza maggiore nei mesi invernali. I risul- tati di Genovese et al. (1971) riportano la comparsa della specie sui litorali dello Stretto di Messina da novembre a maggio, mentre Berdar et al. (1977), censisce la specie per tutto l’arco dell’anno ed in maniera abbondante in termini numerici e di frequenze. Gli stessi autori nel 1988-1989 osservano uno spiaggiamento poco abbondante, con un picco isolato nel mese di agosto (Berdar et al., 1988-1989). I nostri dati riportano una significativa frequenza di E. rissoi nel periodo che va da novembre a maggio, con un totale di 311 esemplari, permettendo così di affermare che la specie ha una reperibilità stabile. Gonostoma denudatum Rafinesque, 1810 Sia Mazzarelli (1909) che Genovese et al. (1971) rin- vengono individui di G. denudatum spiaggiati nei mesi da febbraio a maggio. Gli autori sottolineano come in questo periodo gli esemplari ritrovati fossero maturi sessualmente. Berdar et al. (1977), rinvengono la specie tutto l’anno tranne nel mese di ottobre, mentre nel 1988-1989 la osser- vano nei mesi di gennaio, febbraio ed aprile (Berdar et al., 1988-1989). Durante il nostro censimento la specie non è stata ritrovata in quantità significative, infatti solo due esemplari sono stati trovati spiaggiati nel mese di maggio. Tali risultati ascrivono la specie alla categoria di quelle in forte diminuzione. Hygophum benoiti Cocco, 1838 Secondo Mazzarelli (1909) e Genovese et al. (1971), H. benoiti è tra i mictofidi più comuni, sia in termini di frequenza che di abbondanza. Tali dati sono confermati anche da Berdar et al. (1977) che ritrovano esemplari an- che nel mese di agosto. Berdar et al. (1988-1989) registra- no una diminuzione nella frequenza degli spiaggiamenti di questa specie (esemplari vengono rinvenuti spiaggiati solo nei mesi da gennaio a marzo), sebbene le abbondanze re- stino elevate. Dai dati raccolti nel presente lavoro, la spe- cie ha fatto registrare invece importanti raccolte nei mesi da novembre a maggio (in totale 315 esemplari), con un incremento in termini sia di frequenza che di abbondanza. Ichthyococcus ovatus Cocco, 1838 Mazzarelli (1909) osserva spiaggiamenti di I. ovatus durante tutto l’anno, con notevoli concentrazioni nei mesi di novembre e dicembre. Genovese et al. (1971) lo ritrovano in un numero esiguo di esemplari, con massima concentrazione nei mesi da dicembre a maggio. Berdar et al. (1977) la rinvengono invece tutto l’anno tranne nei mesi di luglio, agosto ed ottobre, mentre nel 1988-1989 non rinvengono alcun esemplare (Berdar et al., 1988-1989). Nel nostro censimento tale specie è stata reperita in basse quantità (12 esemplari in totale) solo nel periodo compreso tra febbraio e maggio. Pertanto, lo spiaggiamento di questa specie può essere considerato caratterizzato da un anda- mento altalenante, con una recente diminuzione. Maurolicus muelleri Gmelin, 1789 Gli spiaggiamenti di questa specie sono piuttosto comuni nello Stretto di Messina. Mazzarelli nel 1909, scrive che gli esemplari si rinvengono spiaggiati in tutti i mesi dell’anno, come confermato più tardi anche da Genovese et al. (1971) e Berdar et al. (1977) (questi ultimi autori la rinvengono tutto l’anno tranne nel mese di luglio). Oltre 10 anni dopo, Berdar et al. (1988-1989) la ritrovano soltanto dal mese di gennaio a quello di marzo. I nostri ritrovamenti sono limitati ai mesi compresi tra novembre e maggio, sebbene con una scarsa abbondanza (in totale n° 16 esemplari). Riteniamo dunque lo spiaggiamento della specie in regressione. Microstoma microstoma Risso, 1810 Secondo Mazzarelli (1909) è possibile ritrovare questa specie spiaggiata in tutti i mesi dell’anno, specialmente da novembre a marzo. Genovese et al. (1971) la rinvengono sui litorali siciliani dello Stretto nel periodo da gennaio a maggio. Berdar et al. (1977) la ritrovano per tutto l’anno tranne nei mesi di luglio ed ottobre, mentre nel 1988-1989 la rinvengono nei mesi di gennaio e di marzo (Berdar et al., 1988-1989). I nostri risultati sono simili a quelli di Genovese et al. (1971), ma gli esemplari hanno fatto regi- strare frequenze e abbondanze più basse (venti in totale). Genericamente possiamo considerarla come specie che spiaggia stabilmente e con lievi incrementi. Myctophum punctatum Rafinesque, 1810 Assieme ad A. hemigymnus è la specie ittica più fre- quente e fa registrare anche abbondanze considerevoli. Mazzarelli (1909) la segnala nei mesi da aprile a giugno. Genovese et al. (1971), riportano ritrovamenti durante tutto l’anno, come confermato anche dalle nostre osservazioni sia in termini di frequenza che di abbondanza. Berdar et al. (1977, 1988-1989), confermano tale andamento anche se con dati di abbondanza superiori rispetto a tutti gli altri censimenti qui presi in esame. Possiamo affermare che la reperibilità della specie sia stabile nel tempo. Nansenia oblita Facciolà, 1887 Mazzarelli (1909) osserva lo spiaggiamento della spe- cie nei mesi da aprile a maggio. Genovese et al. (1971), la segnalano da marzo a maggio, con un’alta frequenza in quest’ultimo mese, mentre qualche esemplare è stato rinvenuto anche nel mese di dicembre. Berdar et al. (1977) la rinvengono nei mesi di gennaio, da marzo a maggio ed a ottobre, mentre successivamente Berdar et al. (1988-1989) ANNALES · Ser. hist. nat. · 31 · 2021 · 1 77 Mauro CAVALLARO et al.: VARIAZIONI PLURIENNALI DEL FENOMENO DELLO SPIAGGIAMENTO DI SPECIE ITTICHE NELLO STRETTO DI MESSINA ... , 69–84 la osservano dal mese di gennaio fino a marzo. Le nostre osservazioni registrano ritrovamenti di esemplari da marzo a maggio con una frequenza piuttosto bassa. Trachipterus trachypterus Gmelin, 1789 Mazzarelli (1909) riporta la notizia che T. trachypterus veniva comunemente catturato nel porto di Messina nei mesi primaverili. Nei mesi di marzo ed aprile ricadono i ritrovamenti di Genovese et al. (1971), che riportano il repe- rimento di sei esemplari. Berdar et al. (1977, 1988-1989), lo segnalano con simili frequenze nei mesi di marzo e aprile. L’unico esemplare da noi ritrovato è stato rinvenuto nel mese di aprile. Tali osservazioni portano a ritenere che la specie sia poco comune e che la sua frequenza di spiaggiamento sia stabile nel tempo. Vinciguerria attenuata Cocco, 1838 Mazzarelli (1909) e Genovese et al. (1971) registravano spiaggiamenti di questa specie in tutti i mesi dell’anno. Ber- dar et al. (1977) la rinvengono tutto l’anno tranne nel mese di luglio, mentre successivamente (Berdar et al., 1988-1989), la reperiscono nei mesi di gennaio e febbraio. I nostri dati riportano una discreta abbondanza di esemplari spiaggiati, con buona continuità nel periodo da febbraio a maggio, con ritrovamenti anche a novembre, per un totale di 144 esemplari. Possiamo considerare lo spiaggiamento di questa specie in lieve flessione. Vinciguerria poweriae Cocco, 1838 Questa specie, morfologicamente molto simile alla con- genere V. attenuata, è stata reperita, nel censimento oggetto del presente lavoro, una volta nel mese di febbraio e due volte nel mese di maggio. Mazzarelli (1909) non la rinviene mentre, Genovese et al. (1971) hanno raccolto ben 123 esemplari in tutto l’arco dell’anno. Il trend positivo è confer- mato nel censimento Berdar et al. (1977), con un notevole incremento. Tuttavia, Berdar et al. (1988-1989) segnalano pochi ritrovamenti limitati al mese di febbraio. La specie spiaggia dunque con frequenze incostanti e abbondanze variabili. CONCLUSIONI Nel presente studio, l’analisi dei dati relativi al monito- raggio del fenomeno dello spiaggiamento ha evidenziato un decremento numerico in termini di specie di teleostei rinvenuti sull’arenile (78 specie), rispetto ai censimenti passati (135 specie rinvenute da Genovese et al. (1971) e 159 rinvenute da Berdar et al. (1977)). Nonostante il forte decremento nel numero di specie e nelle abbondanze di alcuni teleostei, i pesci mesopelagici C. braueri, D. holti, E. rissoi, H. benoiti, I ovatus, M. microstoma, V. attenuata e V. poweriae hanno fanno registrare lievi incrementi di frequen- za e abbondanza. Inoltre, a differenza dei risultati presenti in letteratura (Mazzarelli, 1909; Genovese et al., 1971; Berdar et al., 1988-1989) solo due specie sono state da noi reperite per tutto il corso dell’anno, ovvero A. hemigymnus e M. punctatum. La valutazione comparativa eseguita limitatamente alle stime di abbondanza e reperibilità delle 17 specie prese in considerazione, ha fornito dati interessanti circa l’an- damento del fenomeno dello spiaggiamento nel tempo. Il dato principale è una oggettiva diminuzione delle biomasse reperibili spiaggiate. Quali siano le cause della dimostrata diminuzione quali-quantitativa degli organismi spiaggiati, non è facile da stabilire. Certamente tale fenomeno è da attribuire ad un complesso di combinazioni che vanno dalle variazioni morfologiche delle linee di costa, dovuta alla costante erosione delle spiagge del litorale (Berdar et al., 1993; Boschi & Dragoni, 2000) alla variabilità delle con- dizioni meteomarine fortemente influenzate da fenomeni di inquinamento globale come l’effetto serra (CDP Italy Report 2017), dall’inquinamento della fascia costiera alle pressioni sempre più imponenti della pesca industriale sugli stock ittici con conseguente incidenza sul funzionamento delle catene trofiche (Guglielmo et al., 1995; Potoschi et al., 1996; Battaglia et al., 2013). Differenze e variabilità tra le specie spiaggiate sono inoltre attribuibili ai diversi adattamenti ecologici ed alla morfologia delle specie mesopelagiche. Infatti, pesci di piccole dimen- sioni, come A. hemigymnus, C. braueri e V. attenuata sono maggiormente soggetti a trasporto passivo dovuto alle forti correnti, rispetto a quelli che hanno una maggiore capacità di nuoto e spostamento (Battaglia et al., 2017). Gli individui appartenenti a queste specie risultano più vulnerabili e in particolari condizioni di forti correnti, non sono in grado di contrastare le rapide risalite verticali dalle acque profonde verso gli strati superficiali. Per questo motivo rappresentano le specie più abbondanti tra la fauna spiaggiata. Lo spiaggiamento deve comunque essere considerato un fenomeno non costante e modulato da regole legate ad un numero piuttosto consistente di variabili biologiche, idrodinamiche, meteorologiche, ecc. Pochi sono invece i fattori costanti, quali ad esempio il periodo dell’anno in cui il fenomeno si verifica con più alta frequenza. Tale periodo presenta il picco di massima incidenza durante i mesi in- vernali e primaverili (da Ottobre fino a Maggio) con punte minime nei mesi estivi. Presumibilmente una delle cause è da imputare allo stato di omotermia invernale che favorendo la massima circolazione nella colonna d’acqua, facilita i movimenti attivi verso la superficie. Inoltre, vista la massima frequenza ed abbondanza nei mesi primaverili, un’altra causa è sicuramente l’innescarsi della catena trofica al ter- mine dei mesi invernali che beneficia della mobilizzazione dei nutrienti e dell’aumento della produzione primaria, che favorisce le migrazioni verticali di specie profonde verso le risorse trofiche superficiali e favorisce i cicli riproduttivi delle specie. ANNALES · Ser. hist. nat. · 31 · 2021 · 1 78 Mauro CAVALLARO et al.: VARIAZIONI PLURIENNALI DEL FENOMENO DELLO SPIAGGIAMENTO DI SPECIE ITTICHE NELLO STRETTO DI MESSINA ... , 69–84 VEČLETNE SPREMEMBE V NASEDANJU RIBJIH VRST V MESINSKI OŽINI S POSEBNIM OZIROM NA MEZOPELAŠKE VRSTE Mauro CAVALLARO Departement of Veterinary Sciences, University of Messina, Polo Universitario dell’Annunziata, 98168 Messina - Italy e-mail: mcavallaro@unime.it Giovanni AMMENDOLIA Via C. Pompea, 3 – 98168 Messina – Italy Ignazio RAO Viale Principe Umberto, 119 – 98122 Messina - Italy Alberto VILLARI Salita Villa Contino, 30 - 98124 Messina - Italy Pietro BATTAGLIA Stazione Zoologica Anton Dohrn, Department of Integrative Marine Ecology, SZN, 98168 Messina - Italy POVZETEK Na podlagi rezultatov enoletnega monitoringa nasedanja ribjih vrst vzdolž sicilijanske obale v Mesinski ožini so avtorji primerjali dobljene kvalitativne in kvantitativne podatke s podatki, objavljenimi v predhodnih raziskavah. Opazovanja so bila opravljena vsak dan, ne glede na meteorološke in astronomske razmere, ki so temeljne pri tem pojavu. Podatke je treba tolmačiti s previdnostjo, saj je nasedanje občasen pojav in je odvisen od različnih spremenljivk. Podatki raziskave so pokazali občutno zmanjšanje vrst v primerjavi s predhodnimi raziskavami. Avtorji so poglobili poznavanje o 17 mezopelaških vrstah, ki so bile potrjene tudi v predhodnih raziskavah, da bi poskusili razumeti razvoj tovrstnih sprememb. Ključne besede: nasedanje, Mesinska ožina, mezopelaške vrste ANNALES · Ser. hist. nat. · 31 · 2021 · 1 79 Mauro CAVALLARO et al.: VARIAZIONI PLURIENNALI DEL FENOMENO DELLO SPIAGGIAMENTO DI SPECIE ITTICHE NELLO STRETTO DI MESSINA ... , 69–84 Supplemento 1: Abbondanza numerica delle specie ittiche spiaggiate sulla costa dello Stretto di Messina nel periodo 1.6.2015 – 31.5.2016. Priloga 1: Število primerkov posameznih ribjih vrst, nasedlih na obalah vzdolž Mesinske ožine v obdobju od 1.6.2015 do 31.5.2016. FAMIGLIA SPECIE 2015 2016 TOT G L A S O N D G F M A M Ammodytidae Gymnammodytes cicerelus (Rafinesque, 1810) 1 2 2 2 2 3 24 12 48 Anguillidae Anguilla anguilla Linneo, 1758 2 2 Apogonidae Apogon imberbis (Linneo, 1758) 1 1 2 4 Argentinidae Argentina sphyraena Linneo, 1758 2 2 Atherinidae Atherina boyeri Risso, 1810 7 1 8 Atherinidae Atherina hepsetus Linneo, 1758 2 1 3 Carangidae Trachinotus ovatus (Linneo, 1758) 1 1 2 Carangidae Trachurus trachurus Linneo, 1758 30 30 Carangidae Trachurus picturatus (Bowdich, 1825) 2 2 Carangidae Trachurus mediterraneus (Steindachner, 1758) 52 20 72 Carapidae Carapus acus Brünnich, 1768 1 1 Centriscidae Macroramphosus scolopax (Linneo, 1758) 1 1 Centriscidae Macroramphosus gracilis Lowe, 1839 3 30 137 205 375 Centrolophidae Centrolophus niger (Gemlin, 1789) 3 3 6 Centrolophidae Schedophilus medusophagus Cocco, 1839 3 3 Cepolidae Cepola macrophthalma (Linneo, 1758) 1 1 Chlorophthalmidae Chlorophthalmus agassizi Bonaparte, 1840 2 2 Clinidae Clinitrachus argentatus (Risso, 1810) 1 1 Clupeidae Sardinella aurita Valenciennes, 1847 26 6 3 4 2 7 1 49 Congridae Conger conger Linneo, 1758 2 2 Congridae Gnathophis mystax Delaroche, 1809 3 1 4 Dasyatidae Pteroplatytrygon violacea (Bonaparte, 1832) 1 1 Engraulidae Engraulis encrasicolus Linneo, 1758 5 5 Exocetidae Hirundichthys rondeletii Valenciennes, 1847 16 28 44 Gobiidae Pomatoschistus minutus (Pallas, 1770) 1 1 Gobiidae Lesueurigobius suerii (Risso, 1810) 1 1 Gonostomatidae Cyclothone braueri Jespersen & Tâning,1926 x 50 x 100 150 Gonostomatidae Gonostoma denudatum Rafinesque, 1810 2 2 Labridae Symphodus roissali (Risso, 1810) 1 1 Labridae Labridae ind. 1 1 Lotidae Lotidae ind. 40 40 Lotidae Gaidropsarus mediterraneus Linneo, 1758 3 3 Macrouridae Coelorinchus caelorhincus Risso, 1810 1 1 Macrouridae Nezumia aequalis (Günther, 1878) 1 1 Merluccidae Merluccius merluccius Linneo, 1758 1 1 Microstomatidae Microstoma microstoma Risso, 1810 4 3 2 3 8 20 Microstomatidae Nansenia oblita Facciolà, 1887 4 11 1 16 Moronidae Dicentrarchus labrax (Linneo, 1758) 1 1 Mugilidae Mugilidae ind. 3 3 Mullidae Mullus barbatus Linneo, 1758 1 1 2 Myctophidae Myctophum punctatum Rafinesque, 1810 26 3 2 14 2 30 1 1 12 23 52 20 186 Myctophidae Electrona risso Cocco, 1829 1 30 10 102 34 24 110 311 Myctophidae Hygophum benoiti Cocco, 1838 2 6 5 12 136 134 20 315 Myctophidae Hygophum hygomii Lütken, 1892 1 40 3 44 Myctophidae Diaphus rafinesquii Cocco, 1838 3 4 1 8 Myctophidae Diaphus dumerilii (Bleeker, 1856) 1 1 Myctophidae Diaphus holti Tåning, 1918 1 1 1 2 5 Myctophidae Ceratoscopelus maderensis Lowe, 1839 3 2 5 Myctophidae Notoscopelus elongatus Costa, 1844 4 1 5 Myctophidae Lampanyctus crocodilus Risso, 1810 1 1 Myctophidae Lobianchia gemellarii Cocco, 1838 1 1 Nomeidae Cubiceps gracilis (Lowe, 1843) 1 3 3 7 Paralepididae Lestidiops sphyrenoides (Risso, 1820) 1 1 Paralepididae Paralepis coregonoides Risso, 1826 2 2 Phosichthyidae Vinciguerria attenuata (Cocco, 1838) 2 2 50 45 45 144 Phosichthyidae Ichthyococcus ovatus Cocco, 1838 3 8 1 12 Phosichthyidae Vinciguerria poweriae (Cocco, 1838) 1 2 3 Phycidae Phycis phycis Linneo, 1776 24 4 28 Pomacentridae Chromis chromis Linneo, 1758 13 13 Scomberesocidae Scomberesox saurus Walbaum, 1792 1 1 2 Scombridae Auxis rochei (Risso, 1810) 2 2 4 Scorpaenidae Scorpaenodes arenai Torchio 1962 1 1 Scorpenidae Scorpaena porcus Linneo, 1758 2 1 2 5 Serranidae Anthias anthias (Linneo, 1758) 1 9 2 12 Sparidae Pagellus acarne (Risso 1827) 1 1 1 3 Sparidae Sarpa salpa (Linneo, 1758) 3 1 4 Sparidae Diplodus annularis (Linneo, 1758) 1 1 Sparidae Boops boops (Linneo, 1758) 2 2 Sphyraenidae Sphyraena sphyraena (Linneo, 1758) 1 1 Sternoptychidae Argyropelecus hemigymnus (Cocco, 1829) 2 1 61 1 3 41 204 308 356 977 Sternoptychidae Maurolicus muelleri (Gmelin, 1789) 4 1 5 3 3 16 Stomiidae Chauliodus sloani Bloch & Schneider, 1801 1 1 2 Trachipteridae Zu cristatus Bonelli, 1820 1 1 Trachipteridae Trachipterus trachypterus (Gmelin, 1789) 1 1 Trichiuridae Lepidopus caudatus (Euphrasen, 1788) 1 2 3 Tripterygiidae Tripterygion melanurum Guichenot, 1850 1 1 Tripterygiidae Tripterygion tripteronotum (Risso, 1810) 1 1 2 Xiphidae Xiphias gladius Linneo, 1758 1 1 Larve leptocefaliche 2 10 5 27 39 83 ANNALES · Ser. hist. nat. · 31 · 2021 · 1 80 Mauro CAVALLARO et al.: VARIAZIONI PLURIENNALI DEL FENOMENO DELLO SPIAGGIAMENTO DI SPECIE ITTICHE NELLO STRETTO DI MESSINA ... , 69–84 Supplemento 2: Valutazione comparativa dei dati del presente studio con quelli di Genovese et al. (1971) e di Berdar et al. (1977, 1988-1989). (+ 1-10; ++ 10-50; +++ 50-200; ++++ oltre i 200). Priloga 2: Primerjalna opredelitev podatkov pričujoče raziskave s podatki iz raziskav Genovese et al. (1971) in Berdar et al. (1977, 1988-1989). (+ 1-10; ++ 10-50; +++ 50-200; ++++ več kot 200). SPECIE RIFERIMENTO BIBLIOGRAFICO Gen Feb Mar Apr Mag Giu Lug Ago Set Ott Nov Dic Argyropelecus hemigymnus Genovese et al. (1971) Berdar et al. (1977) Berdar et al. (1988-1989) Presente lavoro ++++ ++++ ++++ + ++++ ++++ ++++ ++ ++++ ++++ +++ ++++ ++++ ++++ +++ ++++ ++++ ++++ +++ ++++ + ++++ +++ + + ++++ ++++ ++++ + ++++ ++++ +++ + ++++ ++++ ++ ++ ++++ ++++ +++ + Ceratoscopelus maderensis Genovese et al. (1971) Berdar et al. (1977) Berdar et al. (1988-1989) Presente lavoro ++ ++ ++ + ++ + ++ ++ + ++ + + + + + + + + + + + + + + Chauliodus sloani Genovese et al. (1971) Berdar et al. (1977) Berdar et al. (1988-1989) Presente lavoro + ++ ++ ++ ++ ++ ++ +++ + +++ + + ++++ ++++ ++ + + +++ + + ++ + + + ++ ++ Cyclothone braueri Genovese et al. (1971) Berdar et al. (1977) Berdar et al. (1988-1989) Presente lavoro ++++ ++++ ++++ + ++ ++++ ++++ +++ ++ ++++ ++ ++ ++++ +++ + + + + + ++ Diaphus holti Genovese et al. (1971) Berdar et al. (1977) Berdar et al. (1988-1989) Presente lavoro + + ++ + ++ ++ ++ + + ++ + + + + + ++ + + Diaphus rafinesquii Genovese et al. (1971) Berdar et al. (1977) Berdar et al. (1988-1989) Presente lavoro ++ + ++ + + + + ++ ++ ++ + + ++ + + + ++ + Electrona rissoi Genovese et al. (1971) Berdar et al. (1977) Berdar et al. (1988-1989) Presente lavoro + ++ + +++ + +++ ++ +++ + ++ ++ ++ ++ ++ +++ +++ ++ ++ +++ + +++ +++ ++++ +++ + ++ ++++ ++ +++ ++ ++ Gonostoma denudatum Genovese et al. (1971) Berdar et al. (1977) Berdar et al. (1988-1989) Presente lavoro + + ++ ++ ++ + ++ + +++ ++ ++++ ++ + + + ++ + + + ++ ++ + Hygophum benoiti Genovese et al. (1971) Berdar et al. (1977) Berdar et al. (1988-1989) Presente lavoro +++ +++ ++++ + ++++ ++++ ++++ ++ ++++ +++ ++ +++ ++++ ++ +++ +++ ++ ++ +++ +++ + ++++ +++ ++ ++++ +++ + ++++ +++ + ++++ +++ + Ichthyococcus ovatus Genovese et al. (1971) Berdar et al. (1977) Berdar et al. (1988-1989) Presente lavoro + ++ ++ + +++ ++ +++ + + ++ ++ + ++ + + + + Maurolicus muelleri Genovese et al. (1971) Berdar et al. (1977) Berdar et al. (1988-1989) Presente lavoro ++ ++ + + ++ +++ ++++ ++++ ++ + ++++ ++ + +++ +++ + + ++ + + + + + ++ + +++ ++ + Microstoma microstoma Genovese et al. (1971) Berdar et al. (1977) Berdar et al. (1988-1989) Presente lavoro + ++ + + ++ ++ + + ++ + + + + + ++ + ++ + + + + Mictophum punctatum Genovese et al. (1971) Berdar et al. (1977) Berdar et al. (1988-1989) Presente lavoro + ++ +++ + ++ ++ ++ ++ +++ ++++ ++ ++ + + ++ ++ +++ +++ ++ ++ +++ +++ ++ + + +++ +++ ++++ + ++ +++ ++ ++++ ++++ + ++ +++ ++ +++ +++ + Nansenia oblita Genovese et al. (1971) Berdar et al. (1977) Berdar et al. (1988-1989) Presente lavoro + ++ ++ ++ +++ + + ++ ++ ++ ++ ++ + + + Trachypterus trachypterus Genovese et al. (1971) Berdar et al. (1977) Berdar et al. (1988-1989) Presente lavoro + + ++ ++ + ++ + ++ Vinciguerria attenuata Genovese et al. (1971) Berdar et al. (1977) Berdar et al. (1988-1989) Presente lavoro ++ +++ + +++ +++ + + ++++ +++ ++ ++++ +++ ++ ++++ +++ ++ + ++ + + ++ + ++ ++ ++ + ++++ +++ Vinciguerria poweriae Genovese et al. (1971) Berdar et al. (1977) Berdar et al. (1988-1989) Presente lavoro + + ++ + ++ +++ + ++ ++ + ++ + + + + + + ++ + +++ ++ ANNALES · Ser. hist. nat. · 31 · 2021 · 1 81 Mauro CAVALLARO et al.: VARIAZIONI PLURIENNALI DEL FENOMENO DELLO SPIAGGIAMENTO DI SPECIE ITTICHE NELLO STRETTO DI MESSINA ... , 69–84 Supplemento 3: Descrizione comparativa dei periodi di ritrovamento delle 17 specie campione nell’ambito dei censi- menti operati da: Mazzarelli (1909), Genovese et al. (1971), Berdar et al. (1977; 1988-1989) ed il presente studio. Priloga 3: Primerjava obdobij, v katerih je bilo najdenih 17 tarčnih vrst v okviru opravljenih vzorčevalnih popisov v študijah Mazzarelli (1909), Genovese et al. (1971), Berdar et al. (1977; 1988-1989) in v pričujoči raziskavi. Specie Mazzarelli (1909) Genovese et al. (1971) Berdar et al. (1977) Berdar et al. (1988-1989) Presente lavoro Argyropelecus hemigymnus tutto l'anno tutto l'anno tutto l'anno da Gennaio a Giugno e da Settembre a Dicembre tutto l'anno Ceratoscopelus maderensis da Gennaio a Marzo Maggio e Agosto da Gennaio a Marzo Gennaio da Aprile a Maggio Chauliodus sloani tutto l'anno da Gennaio a Giugno e Dicembre da Gennaio a Febbraio e da Aprile a Maggio da Gennaio a Marzo e da Maggio a Giugno Maggio Cyclothone braueri tutto l'anno Marzo e Maggio Gennaio e Marzo Da Gennaio a Marzo da Febbraio a Maggio Diaphus holti - da Novembre a Maggio Gennaio - da Dicembre a Maggio Diaphus rafinesquii tutto l'anno da Gennaio a Maggio da Gennaio a Febbraio Gennaio da Novembre a Aprile Electrona rissoi tutto l'anno da Novembre a Maggio da Gennaio a Marzo e Agosto Agosto da Novembre a Maggio Gonostoma denudatum da Febbraio a Maggio da Febbraio a Maggio da Gennaio a Febbraio e Maggio Gennaio Marzo Hygophum benoiti tutto l'anno tutto l'anno da Gennaio a Marzo da Gennaio a Marzo da Novembre a Maggio Ichthyococcus ovatus tutto l'anno da Dicembre a Maggio - - da Febbraio a Maggio Maurolicus muelleri tutto l'anno da Gennaio a Giugno e da Ottobre a Dicembre da Gennaio a Marzo da Febbraio a Marzo da Novembre a Maggio Microstoma microstoma tutto l'anno da Gennaio a Maggio Gennaio e Marzo Gennaio da Gennaio a Maggio Mictophum punctatum da Aprile a Giugno tutto l'anno Gennaio, da Marzo a Giugno e da Agosto a Settembre da Gennaio a Marzo, da Maggio a Giugno, da Agosto a Settembre tutto l'anno Nansenia oblita da Aprile a Maggio da Marzo a Maggio da Gennaio a Marzo da Gennaio a Febbraio da Marzo a Maggio Vinciguerria attenuata tutto l'anno da Gennaio a Giugno, Agosto e da Ottobre a Dicembre da Gennaio a Febbraio - da Febbraio a Maggio Vinciguerria poweriae - da Gennaio a Giugno, Agosto e da Novembre a Dicembre Febbraio - da Marzo a Maggio Trachipterus trachypterus da Marzo a Maggio da Marzo a Maggio da Marzo ad Aprile da Marzo ad Aprile Aprile ANNALES · Ser. hist. nat. · 31 · 2021 · 1 82 Mauro CAVALLARO et al.: VARIAZIONI PLURIENNALI DEL FENOMENO DELLO SPIAGGIAMENTO DI SPECIE ITTICHE NELLO STRETTO DI MESSINA ... , 69–84 BIBLIOGRAFIA Ammendolia, G., M. 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ANNALES · Ser. hist. nat. · 31 · 2021 · 1 85 received: 2021-03-08 DOI 10.19233/ASHN.2021.11 SKELETAL AND PUGHEAD DEFORMITIES IN THE SADDLE BREAM OBLADA MELANURA (OSTEICHTHYES: SPARIDAE) FROM THE TUNISIAN COAST (CENTRAL MEDITERRANEAN SEA) Sihem RAFRAFI-NOUIRA Université de Carthage, Unité de Recherches Exploitation des Milieux aquatiques, Institut Supérieur de Pêche et d’Aquaculture de Bizerte, BP 15, 7080 Menzel Jemil, Tunisia Christian REYNAUD Laboratoire Interdisciplinaire en Didactique, Education et Formation, Université de Montpellier, 2 place Marcel Godechot, B.P. 4152, 34092 Montpellier cedex 5, France Christian CAPAPÉ Laboratoire d’Ichtyologie, Université de Montpellier, case 104, 34095 Montpellier cedex 5, France e-mail: capape@univ-montp2.fr ABSTRACT The article describes the abnormalities of the vertebral column and lateral line observed in a specimen of saddle bream Oblada melanura (Linnaeus, 1758) collected from the northern coast of Tunisia, and an anomaly of the head, i.e., pug-headedness, observed in a second O. melanura from the same area. Despite these mor- phological deformities, both abnormal specimens were able to live in the wild together with normal specimens. The origin of these abnormalities is commented on and discussed. Key words: Oblada melanura, hyperkyphosis, lordosis, environmental pollution, mouth asymmetry, length-weight relationship DEFORMITÀ DI SCHELETRO E TESTA NELL’ORATA OBLADA MELANURA (OSTEICHTHYES: SPARIDAE) LUNGO LA COSTA TUNISINA (MEDITERRANEO CENTRALE) SINTESI L’articolo descrive le anomalie della colonna vertebrale e della linea laterale osservate in un esemplare di orata Oblada melanura (Linnaeus, 1758) pescato lungo la costa settentrionale della Tunisia, e un’anomalia della testa, cioè la testa a carlino, osservata in una seconda O. melanura della stessa area. Nonostante queste deformità morfologiche, entrambi gli esemplari anomali sono stati in grado di vivere in natura assieme agli esemplari normali. L’origine di queste anomalie viene commentata e discussa. Parole chiave: Oblada melanura, ipercifosi, lordosi, inquinamento ambientale, asimmetria della bocca, rapporto lunghezza-peso ANNALES · Ser. hist. nat. · 31 · 2021 · 1 86 Sihem Rafrafi-NOUIRA et al.: SKELETAL AND PUGHEAD DEFORMITIES IN THE SADDLE BREAM OBLADA MELANURA (OSTEICHTHYES: SPARIDAE) FROM ... , 85–94 INTRODUCTION The saddled bream Oblada melanura (Linnaeus, 1758) is known to inhabit shallow coastal waters of the eastern Atlantic from the Bay of Biscay to Angola and marine areas surrounding Madeira, the Cape Verde and Canary Islands (Bauchot & Hureau, 1986). O. melanura is very common in the wider Mediterranean Sea and rather rare in the Black Sea (Louisy, 2002). The reproductive biology of O. melanura has been the object of various studies conducted in the Azores (Morato et al., 2003) and different Mediterranean re- gions, such as Italian waters (Cefali et al., 1987), the Egyptian coast (Zaki et al., 1995), the Adriatic Sea (Pallaoro et al., 2003) and the Syrian coast (Sobar & Lallh, 2017). The species is gregarious, semi-pela- gic, commonly caught in shallow coastal waters not exceeding 30 m (Bauchot & Hureau, 1986), feeding on zooplankton and small invertebrates and fishes (Pallaoro et al., 2003). O. melanura, like other sparid species occurring throughout the Tunisian coast, has commercial value (Khaldi & Chakroun-Marzouk, 2016; Rafrafi- -Nouira, 2016). It is also the fifth most abundant wild fish inhabiting the waters around sea-cage fish farms in the Turkish Aegean Sea (Akyol et al., 2020); specimens reaching up to 357 mm total length have been confirmed in a fish farming area located off Kokar Cove, in Turkish waters (Akyol et al., 2014). The species is rather abundantly caught in northern areas, where it is targeted by fishermen, as its flesh appreciated by the local population (Rafrafi-Noui- ra, 2016). During investigations conducted in the northern Tunisian area since 2010, some specimens have been collected, with two of them displaying morphological deformities. Both abnormal spe- cimens are described in the present article and comments on these abnormalities are provided. MATERIAL AND METHODS A total of 34 specimens of Oblada melanura were sampled between 2010 and 2017 off Ras Jebel, lo- cated on the northern Tunisian coast, of which two specimens found on 23 June 2017 presented physi- cal abnormalities. All specimens were caught by a commercial gill net with 26 mm stretched mesh size, at 37°14’57.53”N and 10°11’52.85”E, on a sandy bottom together with other sparid and labrid speci- es (Fig. 1). The fresh specimens were measured for total length (TL), recorded to the nearest millimetre, and weighed for total body weight (TBW) to the nearest 0.1 gram. Morphometric measurements and meristic counts followed Bauchot & Hureau (1986) and Akyol et al. (2014); they were recorded in both abnormal specimens and compared with the same parameters recorded in a normal specimen (see Tab. 1). The three specimens were fixed in 10% buffered formalin, preserved in 75% formaldehyde and de- posited in the Ichthyological Collection of Institut Supérieur de Pêche et d’Aquaculture de Bizerte (Tunisia), under catalogue numbers: ISPAB-Obl-mel 01 for the normal specimen, ISPAB-Obl-mel 02 for the specimen exhibiting deformities of the vertebral column, and ISPAB-Obl-mel 03 for the pug-headed specimen. Abnormalities of the vertebral column were described following definitions by Elie & Girard (2014) and Jawad & Ibrahim (2018), such as scoliosis (lateral curvature), lordosis (ventral cur- vature), kyphosis (dorsal curvature), and ankylosis (fusion of vertebrae), reported in many cultured and wild species. Additionally, three body regions were taken into consideration, partially following Louiz et al. (2007): anterior or cephalic region, interme- diate or abdominal region, and terminal or caudal region. The second abnormal specimen displayed pug-headedness. Such anomaly is characterised Fig. 1: Map of Tunisia indicating the capture area (rectangle) of Oblada melanura in the northern Tuni- sian coast. GT, Gulf of Tunis. GH, Gulf of Hammamet. GG, Gulf of Gabès. Sl. 1: Zemljevid Tunizije z označeno lokaliteto (pra- vokotnik), kjer sta bila ujeta primerka črnorepke na severni tunizijski obali. GT, zaliv Tunis. GH, zaliv Hammamet. GG, zaliv Gabès. ANNALES · Ser. hist. nat. · 31 · 2021 · 1 87 Sihem Rafrafi-NOUIRA et al.: SKELETAL AND PUGHEAD DEFORMITIES IN THE SADDLE BREAM OBLADA MELANURA (OSTEICHTHYES: SPARIDAE) FROM ... , 85–94 Tab. 1: Morphometric measurements with percentages of standard length (% SL), meristic counts, and total body weight recorded in the three specimens of Oblada melanura collected off the northern Tunisian coast, the normal specimen (ref. ISPAB-Obl-mel 01), the specimen with skeletal deformities (ref. ISPAB-Obl-mel 02), and the pug- -headed specimen (ref. ISPAB-Obl-mel 03). Tab. 1: Morfometrične meritve, izražene v deležih glede na standardno dolžino (% SL), meristična štetja, in celokupna telesna masa treh primerkov črnorepke (Oblada melanura), ujetih ob severni tunizijski obali: normalni primerek (ref. ISPAB-Obl-mel 01), primerek s skeletnimi deformacijami (ref. ISPAB-Obl-mel 02), in primerek z buldoško glavo (ref. ISPAB-Obl-mel 03). References ISPAB-Obl-mel 01 ISPAB-Obl-mel 02 ISPAB-Obl-mel 03 Morphometric measurements mm %TL mm %TL mm %TL Total length 135 100 136 100.0 220.0 100.0 Fork length 115 85.2 115 84.6 195 88.6 Standard length 107 79.3 104 76.5 165 75.0 Head length 30.4 22.5 35 25.7 52 23.6 Eye diameter 16.4 12.1 13 9.6 15 6.8 Pre-orbitary length 12.3 9.1 10 7.4 17 7.7 Post-orbitary length 16.5 12.2 14 10.3 23 10.5 Dorsal fin length 56.2 41.6 56 41.2 95 43.2 Pectoral fin length 10.4 7.7 6 4.4 10 4.5 Pelvic fin length 11 8.1 8 5.9 8.2 3.7 Anal fin length 29.7 22 23 16.9 43 19.5 Caudal fin length 15.2 11.3 12 8.8 16 7.3 Snout length 14.9 11 12 8.8 20 9.1 Body height 43.8 32.4 49 36.0 60 27.3 Pre-dorsal fin length 44.6 33 42 30.9 64 29.1 Pre-pectoral fin length 35.3 26.1 36 26.5 55 25.0 Pre-pelvic fin length 41.01 30.4 41 30.1 66 30.0 Pre-anal fin length 66.6 49.3 68 50.0 110 50.0 Longest spine length of the pectoral 36.6 27.1 38 27.9 5.5 2.5 Thickness 19.9 14.7 18 13.2 23 10.5 Meristic counts ISPAB-Obl-mel 01 ISPAB-Obl-mel 02 ISPAB-Obl-mel 03 Scales on lateral line 67 74 67 Vertebrae 27 36 27 Dorsal fin rays XI+14 XI+14 XI+14 Pectoral fin rays 14 14 14 Pelvic fin rays II+10 II+10 II+10 Anal fin rays III+11 III+11 III+11 Caudal fin rays 20 20 20 Weight (g) 25.2 36.73 104.2 ANNALES · Ser. hist. nat. · 31 · 2021 · 1 88 Sihem Rafrafi-NOUIRA et al.: SKELETAL AND PUGHEAD DEFORMITIES IN THE SADDLE BREAM OBLADA MELANURA (OSTEICHTHYES: SPARIDAE) FROM ... , 85–94 by a malformation occurring on the upper jaw and associated bones of the head. As a result, the upper jaw is shorter than the lower jaw, but both jaws are in relation together (Catelani et al., 2017). A t-test was performed to point out the diffe- rences in the number of line scales and vertebrae between the abnormal and normal specimens of O. melanura. The relation between total length (TL) and total body weight (TBW) was used as a com- plement following Froese et al. (2011), including all specimens, normal and abnormal, to see if these latter could develop in the wild like other normal specimens. This LWR equalled TBW = aTLb, and was converted into its linear regression, expressed in decimal logarithmic co-ordinates, and correla- tions were assessed by least-squares regression as: log TBW = log a + b log TL. Significance of constant b differences was assessed against the hypothesis of isometric growth if b = 3, positive allometry if b > 3, negative isometry if b < 3 (Pauly, 1983). These two latter tests were performed using the STAT VIEW 5.0 logistic model. RESULTS AND DISCUSSION All the collected specimens were identified as O. melanura based on the combination of main morpho- logical characters from Bauchot & Hureau (1986), Golani et al. (2006) and Akyol et al. (2014), such as: body elongated ovoid, snout short, eye large, scales on cheeks, mouth small, anterior margin preopercle and opercle; colour silvery grey, back darker; fine longitudinal dark lines on caudal peduncle, large black saddle surrounding white ring. The 34 sampled specimens ranged between 135 and 220 mm TL and between 27.9 and 108.3 g TBW. The specimen exhibiting skeletal deformities (ref. ISPAB-Obl-mel 02) measured 136 mm TL and weighed 36.7 g (Fig. 2; Tab. 1). An X-ray of this abnormal specimen showed the upper margin to be strongly curved at the level of cephalic region, forming a hump. The lateral line was sinuous, more than it is generally observed in normal specimens, especially in the caudal region. At the level of cephalic and caudal regions, the vertebral column was strongly arched forming hyperkyphosis. The abdominal region displayed hyperlordosis with a similar arch as in the other two deformities (Fig. 3). Conversely, no scoliosis was observed. The lateral line deformation was the main consequence of the vertebral column’s malformation. Jardas & Homen (1977) observed similar deformities in a whiting Merlangius merlangus (Linnaeus, 1758) and a bogue Fig. 2: Oblada melanura from the northern Tunisian coast. A: Abnormal specimen (ref. ISPAB-Obl-mel 02). B: Normal specimen (ref. ISPAB-Obl-mel 01), scale bar = 40 mm. Sl. 2: Oblada melanura iz severne tunizijske obale. A: De- formirani primerek (ref. ISPAB-Obl-mel 02). B: Normalen primerek (ref. ISPAB-Obl-mel 01), merilo = 40 mm. Fig. 3: X-ray of Oblada melanura from the northern Tunisian coast. A: Abnormal specimen (ref. ISPAB-Obl-mel 02). B: Nor- mal specimen (ref. ISPAB-Obl-mel 01), scale bar = 30 mm. Sl. 3: Rentgenski posnetek črnorepke, Oblada melanura, iz severne tunizijske obale. A: Deformiran primerek (ref. ISPAB- -Obl-mel 02). B: Normalen primerek (ref. ISPAB-Obl-mel 01), merilo = 30 mm. ANNALES · Ser. hist. nat. · 31 · 2021 · 1 89 Sihem Rafrafi-NOUIRA et al.: SKELETAL AND PUGHEAD DEFORMITIES IN THE SADDLE BREAM OBLADA MELANURA (OSTEICHTHYES: SPARIDAE) FROM ... , 85–94 Boops boops (Linnaeus, 1758) from the Adriatic Sea and noted that such anomalies are very rare in teleost species from the Adriatic, suggesting that parasitic infection could be the cause of skeletal deformations. On the other hand, Fatnassi et al. (2017) noted that spinal abnormalities found in specimens of gre- ater weever Trachinus draco (Linnaeus, 1758) from the Bay of Bizerte were rather due to environmen- tal conditions, such as high levels of pollutants in the wild. The area was affected by anthropogenic pollution from neighbouring agglomerations and industrial zones, reaching maximum values in the Lagoon of Bizerte (Mzoughi et al., 2002). This latter area is in direct communication with the sea through a navigation canal that spreads the flue of pollutants throughout the Bay of Bizerte (Fatnassi et al., 2017). Additionally, several papers have already pointed out the pollution of the Lagoon of Bizerte as conducive to the abundance of ab- normal fishes inhabiting the area, such as gobiid fish species (Louiz et al., 2007), sparid species (Khenfech et al., 2011) and elasmobranch species (Mnasri et al., 2010) displaying abnormalities of the vertebral column. The pollution of the Bay of Bizerte could also be considered as the main cause of the abnormality observed in the present speci- men of O. melanura. Additionally, Jardas & Homen (1977) noted that such skeletal anomalies are not very rare in teleost species from the Adriatic and suggested parasitic infection as another possible cause. The pug-headed specimen of O. melanura measured 220 mm TL and weighed 104.2 g. An X-ray of this specimen revealed a large deformity of the upper jaw, with the suspensorium and all bones associated with the anterior portion of the neurocranium altered (Fig 4). The pre-maxilla was shorter than in normal specimens, its shape and dis- position were deformed, and the snout was almost absent. The maxilla was almost normal, except in its distal end, where it was slightly altered. The branchial arches, however, appeared to be unaffec- ted. The specimen exhibited an asymmetry between the upper and lower jaws. Following Palmas et al. (2020), the causes of such deformities remain rather obscure, but could be due to epigenetic factors, Fig. 4: A. Pug-headed specimen of Oblada melanura (ref. ISPAB-Obl-mel 03), scale bar = 60 mm. B. X-ray of the pug-headed specimen Oblada melanura, scale bar = 60 mm. C. Head of the same specimen, scale bar = 15 mm. D. X-ray of the head of the same specimen, scale bar = 15 mm. Sl. 4: A. Primerek črnorepke Oblada melanura (ref. ISPAB-Obl-mel 03) s tako imenovano buldoško glavo, merilo = 60 mm. B. Njegov rentgenski posnetek, merilo = 60 mm. C. Glava, merilo = 15 mm. D. Rentgenski posnetek glave, merilo = 15 mm. ANNALES · Ser. hist. nat. · 31 · 2021 · 1 90 Sihem Rafrafi-NOUIRA et al.: SKELETAL AND PUGHEAD DEFORMITIES IN THE SADDLE BREAM OBLADA MELANURA (OSTEICHTHYES: SPARIDAE) FROM ... , 85–94 such as temperature and oxygen fluctuations during egg incubation, prenatal stress of mature females, diet composition in larval stages, and, somewhat less likely, environmental pollution. In relation to the present specimen, a combination of these fac- tors cannot be totally ruled out, however, the area of its capture allows us to consider the pollutants as the main cause of such deformity. On the other hand, Catelani et al. (2017) noted that pug-head deformity is more often observed in teleost species from freshwaters than in those from marine waters, probably due to chemical pollutants. However, Dawson & Heal (1971) reported that specimens in captivity are more affected by such deformity. In accordance with the description by Bauchot & Hureau (1986), the number of scales disposed along the lateral line ranged from 64 to 67. As shown in Table 1, the scales counted in the spe- cimen displaying skeletal deformities (74) signifi- cantly outnumbered those recorded in the normal specimen and the pug-headed specimen (67), with t-test = 29.7, df = 2, p < 0.05. Similarly, the number of vertebrae in the specimen with skeletal deformities (36) significantly outnumbered those recorded in the normal and the pug- -headed specimens (27), with t-test =10, df = 2, p < 0.05. Rafrafi et al. (2019) noted that in L. mormyrus such increased numbers were probably due to the curves of the lateral line and the deformities of the vertebral column. It was also confirmed that the vertebrae were not fused and the specimen did not display an ankylo- sis. Similar patterns were observed in the present specimen. Conversely, deformities of the head played no role in these parameters, the numbers of vertebrae and scales on the lateral line were similar to those recorded in the normal specimen. The deformities observed in the two abnormal specimens did not af- fect their health or development in the wild as a comparison with other normal specimens from the same size class has shown based on line- ar regression between total length versus total body weight (TM, in g) plotted in Fig. 3, with: log TBW = -4.95 + 3.01 * log TL; r = 0.97: n = 34 (Fig. 5) displaying positive allometry. Despite these deformiti- es the residuals generated by this relation did not point out relevant differences between normal and deformed specimens, indicating that the latter were healthy and robust (Palmas et al., 2020). Similar patterns were observed by Khenfech et al. (2011) in the annular sea bream Diplodus annularis (Linnaeus, 1758) and Rafrafi- -Nouira et al. (2019) in the L. mormurys from Tunisian waters. Conversely, Matsuoaka (1987) and Boglione et al. (2006) noted a lethal effect of severe skeletal deformities in teleost species living in natural conditions. Jawad et al. (2010) showed that anomalies hinder the performance of the specimen affecting its capacity to get food and avoid predators. Skeletal deformities are an important factor that downgrades fish production and has a high econo- mic impact, since consumers are wary of purchasing abnormal fish (Panagiotis, 2015). Deformities are a complex mixture of various bone disorders, possibly induced by such unfavourable nutritional factors as phosphorus deficiency, vitamin C deficiency, vitamin K deficiency, and hypervitaminosis, which play an important role in their development in fish farming (Silverstone & Hammell, 2002), but slightly less so in the wild, where, on the other hand, the role environmental factors, such as current veloci- Fig. 5: The total length (TL) versus total body weight (TBM) relation expressed in logarithmic co-ordinates in the specimens of Oblada melanura collected off the northern Tunisian coast. Sl. 5: Odnos med celotno dolžino (TL) in celokupno telesno maso (TBM) primerkov črnorepke iz severne tunizijske obale, izražen v logaritemskih koordinatah. ANNALES · Ser. hist. nat. · 31 · 2021 · 1 91 Sihem Rafrafi-NOUIRA et al.: SKELETAL AND PUGHEAD DEFORMITIES IN THE SADDLE BREAM OBLADA MELANURA (OSTEICHTHYES: SPARIDAE) FROM ... , 85–94 ty, water temperature, and increased exposure to pollutants cannot be ruled out as possible causes (Panagiotis, 2015). Following Jawad & Ibrahim (2018) the increasing temperatures of marine waters throughout the world could play a role in skeletal deformities as well. It is clear from the work of Francour et al. (1994) that the entire Mediterranean has been facing this ecological problem for several decades. Such trou- ble unfortunately also affects the northern coast of Tunisia, which has been progressively invaded by alien species, and cases of abnormalities in fish are more abundant than previously recorded in the area (Rafrafi-Nouira, 2016). ANNALES · Ser. hist. nat. · 31 · 2021 · 1 92 Sihem Rafrafi-NOUIRA et al.: SKELETAL AND PUGHEAD DEFORMITIES IN THE SADDLE BREAM OBLADA MELANURA (OSTEICHTHYES: SPARIDAE) FROM ... , 85–94 DEFORMACIJE SKELETA IN GLAVE PRI ČRNOREPKI, OBLADA MELANURA (OSTEICHTHYES: SPARIDAE) IZ TUNIZIJSKE OBALE (OSREDNJE SREDOZEMSKO MORJE) Sihem RAFRAFI-NOUIRA Université de Carthage, Unité de Recherches Exploitation des Milieux aquatiques, Institut Supérieur de Pêche et d’Aquaculture de Bizerte, BP 15, 7080 Menzel Jemil, Tunisia Christian REYNAUD Laboratoire Interdisciplinaire en Didactique, Education et Formation, Université de Montpellier, 2 place Marcel Godechot, B.P. 4152, 34092 Montpellier cedex 5, France Christian CAPAPÉ Laboratoire d’Ichtyologie, Université de Montpellier, case 104, 34095 Montpellier cedex 5, France e-mail: capape@univ-montp2.fr POVZETEK Avtorji obravnavajo deformacije hrbtenice in pobočnice pri enem primerku črnorepke, Oblada melanura (Linnaeus, 1758), in anomalijo na glavi (tako imenovana buldoška glava) pri drugem primerku; oba sta bila ujeta ob severni obali Tunizije. Kljub morfološkim deformacijam sta bila primerka sposobna življenja v divjini skupaj z normalnimi primerki. Avtorji razpravljajo o izvoru teh anomalij. Ključne besede: Oblada melanura, hiperkifoza, lordoza, onesnaževanje okolja, asimetrija ust, odnos med dolžino in maso ANNALES · Ser. hist. nat. · 31 · 2021 · 1 93 Sihem Rafrafi-NOUIRA et al.: SKELETAL AND PUGHEAD DEFORMITIES IN THE SADDLE BREAM OBLADA MELANURA (OSTEICHTHYES: SPARIDAE) FROM ... , 85–94 REFERENCES Akyol, O., A. Kara & C. Saglam (2014): Maximum size of saddle bream, Oblada melanura (Linnaeus, 1758) (Osteichthyes: Sparidae), in the southern Ae- gean Sea, Turkey. J. Black Sea/Medit. Environ., 20(3), 270-273. Akyol, O., A. Özgül, F.O. Düzbastılar, H. Şen, J.M. Ortiz de Urbina & T. Ceyhan (2020): Seasonal variati- ons in wild fish aggregation near sea-cage fish farms in the Turkish Aegean Sea. Aquac. Rep., 18. DOI: https:// www.x- 10.1016/j.aqrep.2020.100478. Bauchot, M.-L. & C. Hureau (1986): Sparidae. In: J.P. 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ANNALES · Ser. hist. nat. · 31 · 2021 · 1 94 Sihem Rafrafi-NOUIRA et al.: SKELETAL AND PUGHEAD DEFORMITIES IN THE SADDLE BREAM OBLADA MELANURA (OSTEICHTHYES: SPARIDAE) FROM ... , 85–94 Pauly, D. (1983): Some simple methods for assessment of tropical fishes. FAO Fish. Tech. Papers, 234, 3-10. Rafrafi-Nouira, S. (2016): Catalogue raisonné des espèces de poissons capturées devant Ras Jebel et au- tres régions marines de Tunisie septentrionale: aspects morphologiques, biométriques et bio-écologiques. Thesis, Faculty of Sciences of Bizerte, University of Carthage (Tunisia), 509 pp. Rafrafi-Nouira S., C. Reynaud & C. Capapé (2019): Morphological deformities in a striped sea bream Lithognathus mormyrus (Osteichthyes: Sparidae) from northern Tunisian waters (Central Mediterranean Sea). Annales, ser. Hist. Nat., 29(2), 211-218. Silverstone, A.M. & L. Hammell (2002): Spinal de- fromities in farmed Atlantic salmon. The Canad. Veteri J., 43(10), 782-784. Sobar, R. & M. Lallh (2017): Study of morphometric gonads maturity stages and determination reproducti- ve period for saddled bream (Oblada melanura L.) in the coastal waters of Tartous. J. El-bass Univ., 39(28), 157-186. Zaki, M.I., M.B. Abu Shabana & S.S. Assem (1995): The reproductive biology of the saddled bream (Obla- da melanura , L. 1758) from the Mediterranean coasts of Egypt, Oebalia, 31, 17-26. ANNALES · Ser. hist. nat. · 31 · 2021 · 1 95 received: 2021-02-06 DOI 10.19233/ASHN.2021.12 UNCOMMON THERMOPHILIC FISHES FROM THE MARMARA AND BLACK SEAS Murat BILECENOGLU Aydın Adnan Menderes University, Faculty of Arts & Sciences, Department of Biology, 09010 Aydın, TURKEY e-mail: mbilecenoglu@adu.edu.tr Seydi Ali DOYUK Ministry of Agriculture and Forestry, Department of Fisheries and Aquatic Products, Çanakkale, Turkey ABSTRACT The paper discusses the occurrences of three fish species in previously unrecorded localities in Turkey. Centrolophus niger (Gmelin, 1789) is a new addition to the fauna of the Sea of Marmara, while Alectis alex- andrina (Geoffroy Saint-Hilaire, 1817) and Coryphaena hippurus Linnaeus, 1758 are recorded for the first time in the Black Sea ecosystem. The range expansion of these taxa is most likely facilitated by increased seawater temperatures in the region. Key words: Centrolophus niger, Alectis alexandrina, Coryphaena hippurus, Sea of Marmara, Black Sea PESCI TERMOFILI NON COMUNI DEL MAR DI MARMARA E DEL MAR NERO SINTESI Nell’articolo vengono presentate nuove segnalazioni di tre specie di pesci in località della Turchia dove pre- cedentemente non erano state ritrovate. Centrolophus niger (Gmelin, 1789) è una nuova aggiunta alla fauna del Mar di Marmara, mentre Alectis alexandrina (Geoffroy Saint-Hilaire, 1817) e Coryphaena hippurus Linnaeus, 1758 vengono ritrovati per la prima volta nell’ecosistema del Mar Nero. L’espansione dell’areale di questi taxa è molto probabilmente facilitata dall’innalzamento della temperatura dell’acqua marina nella regione. Parole chiave: Centrolophus niger, Alectis alexandrina, Coryphaena hippurus, Mar di Marmara, Mar Nero ANNALES · Ser. hist. nat. · 31 · 2021 · 1 96 Murat BILECENOGLU & Seydi Ali DOYUK: UNCOMMON THERMOPHILIC FISHES FROM THE MARMARA AND BLACK SEAS, 95–100 INTRODUCTION Several thermophilic fish species native to subtropical or tropical environments are extending their biogeographical ranges to northern sectors of the Mediterranean Sea, primarily as a result of seawater warming (Francour et al., 1994; Azzurro, 2008; Azzurro et al., 2011; Bianchi et al., 2017). This phenomenon has also been observed along the Turkish coastline, especially in the Marmara and Black Seas, where rapid change in fish fauna has been observed during the past decade. The mean surface water temperature of both seas, which was 15.1°C during the 1970–1979 period, experienced a significant increase to 16.3 °C and 16.6 °C in the Black Sea and the Sea of Marmara, respectively, during the 2010–2019 period (TSMS, 2021). The change of hydrographical conditions of these two unique semi-enclosed seas is manifest in the influx to the region of an increasing number of non- native fish with warm water affinities. For example, Trachinotus ovatus (Linnaeus, 1758) has recently penetrated as far as the Strait of Istanbul, the en- trance to the Black Sea, with possible indications of population establishment (Bilecenoglu & Öztürk, 2019). Likewise, occurrences of typical Mediterra- nean taxa, such as Mustelus asterias Cloquet, 1819 and Serranus hepatus (Linnaeus, 1758) in the Black Sea (Eryılmaz et al., 2011; Dalgıç et al., 2013), and Dasyatis tortonesei Capapé, 1975 and Aetomylaeus bovinus (Geoffroy Saint-Hilaire, 1817) in the Sea of Marmara (Yıldız et al., 2016, Bilecenoglu, 2019) can be interpreted as a consequence of global warming. In this paper, we are presenting new information on the distribution range expansion of three ther- mophilic fish species: Centrolophus niger (Gmelin, 1789), which was recorded for the first time in the Sea of Marmara, and Alectis alexandrina (Geoffroy Saint-Hilaire, 1817) and Coryphaena hippurus Lin- naeus, 1758, which are new to Black Sea fauna. MATERIAL AND METHODS On 15 November 2020, a single specimen of C. niger measuring 79 cm in total length and weighing 6880 g was captured by trammel net off Hamzaköy (Çanakkale, Sea of Marmara, Fig. 1), at a depth of 2 m. Owing to the uncommon occurrence of this spe- cies, the fishermen immediately informed the local fisheries authorities (second author) and provided several photographs of the captured individual. During regular screening of online Turkish news- papers for any uncommon marine fish reports, an occurrence of a large-sized A. alexandrina (8400 g in weight) captured from Sinop coasts (central Black Sea, Fig. 1) was unexpectedly encountered. The news appeared on 17 November 2020 in sev- eral local and national newspapers, and is worth including herein due to its taxonomical importance. The length of the fish was not mentioned, but the associated photograph indicated a total length of at least 80 cm. On 3 January 2021, a skin diver captured a single individual of C. hippurus of an approximate total length of 50 cm, using a speargun at a depth of 10 m, in the Akçakoca coast of Zonguldak (western Black Sea, Fig. 1). The diver shared the photographs of the fish on the social media (Facebook) and later forwarded them to the first author for taxonomic identification. RESULTS AND DISCUSSION Based on the combination of characters includ- ing elongate body, large mouth, single dorsal fin (originating slightly behind the end of pectoral fin), very small scales, anteriorly arched lateral line, and uniformly dark brown body color, the Marmara specimen of C. niger was positively identified from the photograph (Fig. 2A), matching the descrip- tion by Haedrich (1986). Previously regarded as rare in the Mediterranean Sea, based on several records from distant localities in recent years, C. niger has proved to be more common and wide- spread, and the increasing number of observations of the species is likely related to climate change (Capapé et al., 2017). Adults of the species tend Fig. 1: Capture and observation localities of Centro- lophus niger (1), Coryphaena hippurus (2) and Alectis alexandrina (3) along the Turkish coast. Sl. 1: Lokalitete, kjer so bile ujete ali opažene vrste Cen- trolophus niger (1), Coryphaena hippurus (2) in Alectis alexandrina (3) vzdolž turških obal. ANNALES · Ser. hist. nat. · 31 · 2021 · 1 97 Murat BILECENOGLU & Seydi Ali DOYUK: UNCOMMON THERMOPHILIC FISHES FROM THE MARMARA AND BLACK SEAS, 95–100 Fig. 2: A) The Centrolophus niger individual captured from Gelibolu coast, Sea of Marmara (photograph courtesy of C. Konur); B) Alectis alexandrina from Sinop, central Black Sea (source: https://www.haber- ler.com/sinop-ta-yakalanan-dev-iskender-baligi-gorenleri-13741950-haberi/), C) Coryphaena hippurus spearfished from the Akçakoca shore in the western Black Sea (photograph courtesy of V. Erdogan). Sl. 2: A) Primerek črnuha, Centrolophus niger, iz obale pri Geliboli, Marmarsko morje (Foto: C. Konur); B) primerek vrste Alectis alexandrina iz Sinop, osrednje Črno morje (vir: https://www.haberler.com/si- nop-ta-yakalanan-dev-iskender-baligi-gorenleri-13741950-haberi/), C) primerek delfinke, Coryphaena hippurus, ulovljen s podvodno puško na obali Akçakoca v zahodnem Črnem morju (Foto: V. Erdogan). ANNALES · Ser. hist. nat. · 31 · 2021 · 1 98 Murat BILECENOGLU & Seydi Ali DOYUK: UNCOMMON THERMOPHILIC FISHES FROM THE MARMARA AND BLACK SEAS, 95–100 to inhabit deep waters (Haedrich, 1986), however, our recent finding is from a very shallow shore (2 m) in the Gelibolu coast, where maximum depths do not exceed 70 m. The hydrography of the Strait of Çanakkale is governed by a two-layered flow system, i.e., a surface layer flowing from the Black Sea towards the Aegean Sea, and a bottom layer comprising Mediterranean waters flowing towards the Black Sea (Beşiktepe et al., 1994). The most plausible explanation would thus be that the spe- cies has penetrated the Strait of Çanakkale from the Aegean Sea through the bottom flow layer and was incidentally captured at the southwestern margin of the Sea of Marmara. Monitoring the distribution of marine taxa through data obtained from online newspapers is a quite new low-cost and non-destructive approach, which has proved to be efficient in providing valu- able information, including existence of previously unknown species and/or significant range expan- sions (Kabasakal & Bilecenoglu, 2020). The occur- rence data of an adult individual of A. alexandrina in the central Black Sea coast (Fig. 2B) are also provided accordingly. This thermophilic carangid is prevalent along the entire northern Levant shores extending as far as Gökova Bay in the southern Aegean coast of Turkey, but prior to this occurrence there were no observations in relation to the species from the northern Aegean or Marmara or Black Seas (Bilecenoglu et al., 2014). This recent occurrence in the Sinop coast, at least 900 nautical miles away from Gökova Bay, is therefore surprisingly interest- ing. The unique coloration and, even more so, the body shape of C. hippurus captured from the western Black Sea were instrumental in the identification of the species based on the photograph (Fig. 2C), and its distinction from the congeneric C. equiselis, as the body depth equaled less than 25% of standard length in adults, and the pectoral fin represented over a half of the length of the head (Collette, 1986; Froese & Pauly, 2019). The epipelagic C. hippurus is distributed worldwide in tropical and subtropical seas, including the Mediterranean Sea (Collette, 1986). Naturally occurring in the Levant and Aegean Sea shores of Turkey (Bilecenoglu et al., 2014), the species has penetrated into the western part of the Sea of Marmara over the past decade (Artüz & Kubanç, 2015). Since the species displays a highly migratory behavior (Froese & Pauly, 2019), its influx into the Black Sea via the Strait of Istanbul is a reasonable explanation. The Marmara and Black Seas have quite similar ichthyofaunas (56% similarity based on presence vs. absence of species, Bilecenoglu et al., 2002), which is to be expected considering that they evolved together during the same geological eras. The in- creasing number of thermophilic fish recorded from the region should be considered a serious threat that might lead to an undeterred biological homogeniza- tion, commonly known as “Mediterraneanization” (Boltachev & Karpova, 2014). Fish species near the limits of their thermal distribution are obvious can- didates for range shifts given the rising temperatures (Campana et al., 2020), so we may assume that sev- eral other species have the potential to advance to- wards the colder sectors of the Mediterranean Basin. The monitoring of the distribution patterns of native fish taxa can therefore provide valuable bioecologi- cal information, which should be collected using all novel methodological means (i.e., citizen science, social media, print/online media, etc.) in addition to traditional methods. ACKNOWLEDGEMENTS The authors would like to thank to the local fish- ermen Cengiz Konur and Veli Erdogan for providing data and photographs of Centrolophus niger and Cory- phaena hippurus, respectively. ANNALES · Ser. hist. nat. · 31 · 2021 · 1 99 Murat BILECENOGLU & Seydi Ali DOYUK: UNCOMMON THERMOPHILIC FISHES FROM THE MARMARA AND BLACK SEAS, 95–100 NENAVADNE TOPLOLJUBNE RIBE IZ MARMARSKEGA IN ČRNEGA MORJA Murat BILECENOGLU Aydın Adnan Menderes University, Faculty of Arts & Sciences, Department of Biology, 09010 Aydın, TURKEY e-mail: mbilecenoglu@adu.edu.tr Seydi Ali DOYUK Ministry of Agriculture and Forestry, Department of Fisheries and Aquatic Products, Çanakkale, Turkey POVZETEK Avtorji poročajo o novih pojavih treh vrst rib iz lokalitet, na katerih doslej še niso bile potrjene v Turčiji. Centrolophus niger (Gmelin, 1789) je nova vrsta v favni Marmarskega morja, medtem, ko sta bili vrsti Alectis alexandrina (Geoffroy Saint-Hilaire, 1817) in Coryphaena hippurus Linnaeus, 1758 prvič potrjeni v ekosistemu Črnega morja. Širjenje areala teh vrst je najverjetneje povezano z višjimi temperaturami vode v regiji. Ključne besede: Centrolophus niger, Alectis alexandrina, Coryphaena hippurus, Marmarsko morje, Črno morje ANNALES · Ser. hist. nat. · 31 · 2021 · 1 100 Murat BILECENOGLU & Seydi Ali DOYUK: UNCOMMON THERMOPHILIC FISHES FROM THE MARMARA AND BLACK SEAS, 95–100 REFERENCES Azzurro, E. (2008): The advance of thermophilic fishes in the Mediterranean Sea: overview and meth- odological questions. In: Briand, F. (ed.): Climate Warming and Related Changes in Mediterranean Marine Biota, CIESM Workshop Monographs 35, CIESM, Monaco, pp. 39-46. Artüz, M.L. & N. Kubanç (2015): First record of Coryphaena hippurus (Linnaeus, 1758) from the Sea of Marmara. Thalassas, 31(1), 9-13. Azzurro, E., P. Moschella & F. Maynou (2011): Tracking signals of change in Mediterranean fish diversity based on local ecological knowledge. PLoS One, 6: e24885. Besiktepe, S.T., H.I. Sur, E. Ozsoy, M.A. Latif, T. Oguz & U. Unluata (1994): The circulation and hydrography of the Marmara Sea. Progr. Oceanogr., 34, 285-334. 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El Kamel- Moutalibi (2017): On the occurrence of blackfish Centrolophus niger (Osteichthyes: Centrolophidae) from the Tunisian coast (central Mediterranean). Cah. Biol. Mar., 58(1), 117-120. Collette, B.B. (1986): Coryphaenidae. In: Whitehead, P. J. P., M. L. Bauchot, J.-C. Hureau, J. Nielsen & E. Tor- tonese (eds.): Fishes of the North-eastern Atlantic and the Mediterranean, Vol. 2. Unesco, Paris, pp. 845-846. Dalgıç, G., A. Gümüş, & M. Zengin (2013): First re- cord of brown comber Serranus hepatus (Linnaeus, 1758) for the Black Sea. Tr. J. Zool., 37(4), 523-524. Eryılmaz, L., E. Yemişken & C. Dalyan (2011): The first documented record of genus Mustelus (Chondrichthyes: Triakidae) in the Black Sea. Tr. J. Fish. Aquat. Sci., 11(1), 157-160. Francour, P., C. Boudouresque, J. Harmelin, M.L. Harmelin-Vivien, & J.P. Quignard (1994): Are the Medi- terranean waters becoming warmer? Information from biological indicators. Mar. Pollut. Bull., 28, 523-526. Froese, R. & D. Pauly (2019): FishBase. World Wide Web electronic publication [version 12/2019]. http:// www.fishbase.org. Haedrich R.L. (1986): Centrolophidae. In: White- head, P. J. P., M. L. Bauchot, J.-C. Hureau, J. Nielsen & E. Tortonese (eds.): Fishes of the North-eastern Atlantic and the Mediterranean, Vol. 3. Unesco, Paris, pp. 1177-1182. Kabasakal, H. & M. Bilecenoglu (2020): Shark infested internet: an analysis of internet-based media reports on rare and large sharks of Turkey. FishTaxa, 16, 8-18. Turkish State Meteorological Service (2021): Of- ficial statistics, sea water temperature analysis. https:// www.mgm.gov.tr/veridegerlendirme/il-ve-ilceler- istatistik.aspx?k=K [Accessed on 28 January 2021) Yıldız, T., E. Yemişken, F.S. Karakulak, U. Uzer, C. Dalyan & I.K. Oray (2016): A new record of dasyatid fish from the Sea of Marmara: Tortonese’s stingray, Dasyatis tortonesei Capapé, 1975 (Dasyatidae). J. App. Ichthyol., 32(4), 721-723. ANNALES · Ser. hist. nat. · 31 · 2021 · 1 101 received: 2021-02-01 DOI 10.19233/ASHN.2021.13 FIRST SUBSTANTIATED RECORD OF ARMLESS SNAKE EEL DALOPHIS IMBERBIS (OSTEICHTHYES: OPHICHTHIDAE) FROM THE SYRIAN COAST (EASTERN MEDITERRANEAN SEA) Christian CAPAPÉ Laboratoire d’Ichtyologie, case 104, Université de Montpellier, 34 095 Montpellier cedex 5, France e-mail: capape@univ-montp2.fr Adib SAAD, Ahmad SOLAIMAN, Issa BARAKAT & Waad SABOUR Marine Sciences Laboratory, Faculty of Agriculture, Tishreen University, Lattakia, Syria ABSTRACT The present note reports the first record of armless snake eel Dalophis imberbis (Delaroche, 1809) from the coast of Syria. It describes the specimen and provides comments about its distribution. This record marks the easternmost extension range of the species in the Mediterranean Sea, but the establishment of a viable popula- tion in the Levant Basin remains questionable; more captures are needed to confirm this hypothesis. Key words: Dalophis imberbis, description, morphometric measurements, extension range, eastern Levant Basin PRIMO RITROVAMENTO DOCUMENTATO DELLA BISCIA DI MARE MEZZANA DALOPHIS IMBERBIS (OSTEICHTHYES: OPHICHTHIDAE) LUNGO LA COSTA SIRIANA (MEDITERRANEO ORIENTALE) SINTESI La presente nota riporta il primo ritrovamento della biscia di mare mezzana Dalophis imberbis (Delaroche, 1809) lungo la costa della Siria. Gli autori descrivono l’esemplare e commentano la distribuzione della specie. Questo ritrovamento rappresenta il punto più orientale dell’estensione della specie nel Mar Mediterraneo, ma la presenza di una popolazione vitale nel bacino del Levante rimane discutibile. Saranno necessarie ulteriori catture per confermare questa ipotesi. Parole chiave: Dalophis imberbis, descrizione, misure morfometriche, range di estensione, bacino orientale del Levante ANNALES · Ser. hist. nat. · 31 · 2021 · 1 102 Christian CAPAPÉ et al.: FIRST SUBSTANTIATED RECORD OF ARMLESS SNAKE EEL DALOPHIS IMBERBIS (OSTEICHTHYES: OPHICHTHIDAE) FROM THE SYRIAN COAST ..., 101–106 INTRODUCTION The armless snake eel Dalophis imberbis (De- laroche, 1809) is reported from the eastern North Atlantic as far north as Portugal (Quéro et al., 2003) and south of the Strait of Gibraltar, off Morocco (Lloris & Rucabado, 1998) and Mauritania (Maurin & Bonnet, 1970). Southward, the species is unknown between Senegal (Cadenat, 1951; Diatta, pers. comm., 2021) and the Gulf of Guinea (Blache et al., 1970; Leiby, 1990). Following Bauchot (1986) the species is recorded in the wider Mediterranean, is prob- ably rare off the French coast (Bauchot & Pras, 1980; Béarez et al., 2017), but quite common in Italian waters (Bonifazi et al., 2019). Likic et al. (2015) noted that D. imberbis is caught in low densities in the Adriatic Sea. Southward, the species spawned in the Bay of Algiers (Bauchot, 1986) but gener- ally remains poorly known off the Maghreb shore, Algeria (Dieuzeide et al., 1954; Refes et al., 2010) and Tunisia (Bradaï et al., 2004). Eastward, the species is reported in Greek waters (Pa- paconstantinou, 2014) and in the Turkish coasts (Bilecenoğlu et al., 2014), and the Levant Basin constitutes its eastern- most extension range in the Mediterranean Sea (El Sayed et al., 2017; Golani, 2005; Bariche & Fricke, 2019). Routine monitoring has been conducted for several decades to assess the fish diversity in Syrian marine waters and sev- eral species unknown among the local ichthyofauna have periodically been found and described (Saad, 2005; Ali, 2018). Recently, a specimen of D. imberbis was collected for the first time in this area. The specimen is presented in this note and some comments are provided concerning its distri- bution in the local area and in the wider Mediterranean Sea. MATERIAL AND METHODS On 25 April 2020, a specimen of armless snake eel Dalophis inberbis (Delaroche, 1809) was caught with a hand fishing net off Tartous Beach, at 35 86’93’’E and 34°90’39’’N, at a depth of 13 metres, on rocky bottom (Fig. 1). It was delivered Fig. 1: Map of the Syrian coast indicating (black star) the capture site of Dalophis imberbis (off Tartous Beach). Sl. 1: Zemljevid sirske obale z označbo lokalitete, kjer je bil ujet primerek kačaste jegulje (Dalophis imberbis), ujete ob plaži Tartous Beach. ANNALES · Ser. hist. nat. · 31 · 2021 · 1 103 Christian CAPAPÉ et al.: FIRST SUBSTANTIATED RECORD OF ARMLESS SNAKE EEL DALOPHIS IMBERBIS (OSTEICHTHYES: OPHICHTHIDAE) FROM THE SYRIAN COAST ..., 101–106 to the laboratory for thorough examination fol- lowing Bello et al. (2014). Some morphological measurements of the specimen were made and recorded to the nearest millimetre and the nearest gram (see Tab. 1). The specimen was fixed in 10 % buffered formalin, preserved in 75% ethanol and deposited in the Ichthyological Collection of the Laboratory of Marine Sciences and Aquatic Environment at Tishreen University, in Lattakia (Syria) under catalogue number MSL 23-2020-D. imb. RESULTS AND DISCUSSION The Syrian specimen (Fig. 2) was identif ied as D. imberbis via a combination of the fol- lowing main morphological characters: body very elongate, snake-like and cylindrical, with similar thickness from head to tail , and scale- less; vent in anterior region of body; snout short conical, eye small compared to the head, dorsal part of head and lips covered with vil losit ies; teeth slightly curved and conical; gil l openings latero-ventral; caudal and pelvic f ins absent, pectoral f ins rudimentary, dorsal and anal f ins low, placed in a deep dermal groove; colour of head, back and base of dorsal f in grey-violet, dotted with black, belly and underside of head yellowish. The description of the species, including mor- phological characters, colour and morphometric measurements (see Tab. 1), is in total accordance with Tortonese (1970), Bauchot (1986), Quéro et al. (2003) and Bonifazi et al. (2019). D. imberbis could be added to the list of fish species record- ed in the Syrian coast, completing the previous works of Saad (2005) and Ali (2018). Following Bonifazi et al. (2019), the scarcity of the species throughout its capture areas is probably due to its low economical interest. The species is rather considered as common by-catch by fishermen (Busalacchi et al., 2010). However, Bonifazi et al. (2019) reported records of massive beaching of D. imberbis from the coast of Ostia (central Mediterranean Sea), observed on 6 March 2017, after a huge wintry storm. Such a phenomenon Tab. 1: Morphometric measurements and total body weight of Dalophis imberbis (caught off Tartous Beach). Tab. 1: Morfometrične meritve in celokupna telesna masa kačaste jegulje (Dalophis imberbis), ujete ob plaži Tartous Beach. Reference MSL-23-2020-D. imb Morphometric characters (mm) mm %TL Total length (TL) 260 100 Preanal length (LPA) 97.5 37.5 Predorsal length (LPD) 25.2 9.7 Prepectoral length (LPP) 21.9 8.4 Dorsal fin length (LD) 229.1 88.1 Anal fin length (La) 167.7 64..5 Pectoral fin length (Lp) 4.8 1.8 Body depth (H) 4.8 1.8 Head length (C) 20.1 7.7 Eye diameter (O) 1.3 0.5 Preorbital length (PO) 6.2 2.4 Interorbital length (Io) 1.5 0.6 Length of lower jaw 12.7 4.8 Total body weight (gram) 10.16 Fig. Specimen of Dalophis imberbis (caught off Tartous Beach), Syrian coast, scale bar = 50 mm. Sl. 2: Primerek kačaste jegulje (Dalophis imberbis), ujete ob plaži Tartous Beach (sirska obala), merilo = 50 mm. ANNALES · Ser. hist. nat. · 31 · 2021 · 1 104 Christian CAPAPÉ et al.: FIRST SUBSTANTIATED RECORD OF ARMLESS SNAKE EEL DALOPHIS IMBERBIS (OSTEICHTHYES: OPHICHTHIDAE) FROM THE SYRIAN COAST ..., 101–106 could occur anywhere in the Mediterranean Sea because D. imberbis is commonly hiding in burrows in the sand and mud of shallow coastal waters at up to 80 m of depth (Bauchot, 1986). The present capture of D. imberbis confirms the presence of the species in the Levant Basin, and together with the captures reported by Golani (2005) and Bariche & Fricke (2019) marks the easternmost extension range of the species in the Mediterranean Sea. However, more records are required to establish the occurrence of a viable population of D. imberbis in the region. ANNALES · Ser. hist. nat. · 31 · 2021 · 1 105 Christian CAPAPÉ et al.: FIRST SUBSTANTIATED RECORD OF ARMLESS SNAKE EEL DALOPHIS IMBERBIS (OSTEICHTHYES: OPHICHTHIDAE) FROM THE SYRIAN COAST ..., 101–106 PRVI DOKUMENTIRAN PRIMER POJAVLJANJA KAČASTE JEGULJE, DALOPHIS IMBERBIS (OSTEICHTHYES: OPHICHTHIDAE), VZDOLŽ SIRSKE OBALE (VZHODNO SREDOZEMSKO MORJE) Christian CAPAPÉ Laboratoire d’Ichtyologie, case 104, Université de Montpellier, 34 095 Montpellier cedex 5, France e-mail: capape@univ-montp2.fr Adib SAAD, Ahmad SOLAIMAN, Issa BARAKAT & Waad SABOUR Marine Sciences Laboratory, Faculty of Agriculture, Tishreen University, Lattakia, Syria POVZETEK Avtorji poročajo o prvem primeru pojavljanja kačaste jegulje Dalophis imberbis (Delaroche, 1809) iz sirske obale. Opisujejo ujeti primerek in razpravljajo o razširjenosti vrste. Gre za najbolj vzhodno pojavljanje te vrste v Sredozemskem morju. Kljub temu je prisotnost vitalne populacije te vrste v Levantskem bazenu vprašljiva. 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Calderini, Bologna, 564 pp. ANNALES · Ser. hist. nat. · 31 · 2021 · 1 107 received: 2021-04-20 DOI 10.19233/ASHN.2021.14 LENGTH-WEIGHT RELATIONSHIPS AND METRIC CHARACTERS OF THE ATLANTIC HORSE MACKEREL, TRACHURUS TRACHURUS (PERCIFORMES: CARANGIDAE), CAUGHT IN BÉNI-SAF BAY, WESTERN MEDITERRANEAN (ALGERIA) Khaled RAHMANI & Fatiha KOUDACHE University Djillali Liabes, Ecodeveloppement of spaces Laboratory, Sidi Bel Abbès 22000, Algeria e-mail: khaled46310@gmail.com Amaria Latefa BOUZIANI & Alae Eddine BELMAHI Laboratory Network for Environmental Monitoring (LRSE), Department of Biology, Faculty of Life and Nature, University of Ahmed Benbella Oran 1, BP 1524 El M’naouer, 31000 Oran, Algeria ABSTRACT The present study is to describe the morphometric characteristics of the Atlantic horse mackerel, Trachurus trachurus (Linnaeus, 1758), from Béni-Saf Bay (Algeria). A total of 355 specimens were investigated, sampled between November 2016 and October 2017, and consisting of 47.04% males, 44.79% females, and 8.17% unde- termined individuals. The total length of the observed fish ranged from 7.4 to 35.4 cm. Seventeen measurements were carried out for each specimen. The length-weight relationship was investigated, and the results showed that the increase in size is proportional to the increase in weight (isometric allometry). The analysis of 17 metric characters allowed us to determine the type of growth allometry; all the characters presented a lowering allometry, with six characters displaying sexual dimorphism, five in favor of the males and one in favor of females. Key words: Atlantic horse mackerel, Trachurus trachurus, length-weight relationship, metric characters, Béni-Saf Bay, Algeria RELAZIONI LUNGHEZZA-PESO E CARATTERI METRICI DEL SUGARELLO, TRACHURUS TRACHURUS (PERCIFORMES: CARANGIDAE), CATTURATO NELLA BAIA DI BÉNI-SAF, MEDITERRANEO OCCIDENTALE (ALGERIA) SINTESI L’articolo riporta le caratteristiche morfometriche del sugarello, Trachurus trachurus (Linnaeus, 1758), pro- veniente dalla baia di Béni-Saf (Algeria). Un totale di 355 esemplari sono stati campionati tra novembre 2016 e ottobre 2017, con il 47,04 % di maschi, il 44,79 % di femmine e l’8,17 % di indeterminati. La lunghezza totale degli esemplari variava da 7,4 a 35,4 cm. Sono state eseguite 17 misure per ogni esemplare. In merito al rapporto lunghezza-peso è stato evidenziato che l’aumento della taglia è proporzionale all’aumento del peso (allometria isomerica). L’analisi di 17 caratteri metrici ha permesso di determinare il tipo di allometria di crescita. Tutti i caratteri presentano un’allometria decrescente. Sei caratteri sono legati al dimorfismo sessuale, cinque a favore dei maschi e uno a favore delle femmine. Parole chiave: sugarello, Trachurus trachurus, rapporto lunghezza-peso, caratteri metrici, baia di Béni-Saf, Algeria ANNALES · Ser. hist. nat. · 31 · 2021 · 1 108 Khaled RAHMANI et al.: LENGTH-WEIGHT RELATIONSHIPS AND METRIC CHARACTERS OF THE ATLANTIC HORSE MACKEREL, TRACHURUS TRACHURUS ... , 107–122 INTRODUCTION The Atlantic horse mackerel, Trachurus trachu- rus (Linnaeus, 1758), is a gregarious species of the Carangidae family. It can be found in circa-littoral bottoms and even in the higher horizon of the bathyal zone (Athanassios & Konstantinos, 2015). The species is common in shallow coastal waters of the north-eastern Atlantic, from Iceland to the Islands of Cape Verde. It is also found in the Medi- terranean, including the Sea of Marmara and, more rarely, in the Black Sea (Polonsky, 1969; Arneri, 1983), the Eastern Channel, and the North Sea. T. trachurus is a migratory species; it lives and hunts in shoals. Usually, it migrates towards the coast in summer, and returns to offshore waters in winter; it can be found close to the sea bottom, where it lives between 50 and 400 m of depth; the species also has the capacity to adapt to brackish water (Santic et al., 2003). In the Mediterranean Basin, T. trachurus is very common (Fezzani et al., 2002), living in open water and near sandy bottoms; it feeds primarily on fish, such as gobies, anchovy, sardine, and only on certain shellfish (Ameri, 1983; Kerstan, 1985). Horse mackerel has been the subject of sev- eral studies on reproduction (Korichi, 1988; Ta- hari, 2011; Aydin & Erdoğan, 2018; Gherram, 2019; Rahmani & Koudach, 2020; Rahmani et al., 2020a), growth (Karlou-Riga & Sinis, 1997; Moutopoulos et al., 2002; Abaunza et al., 2003; Jardas et al., 2004; ğlkyaz et al., 2008; Ak et al., 2009; Costa, 2010; Torres et al., 2012; Kerkich et al., 2013; Erdoğan et al., 2016; Bensahla et al., 2017; Azzouz et al., 2018; Gherram, 2019; Rahmani, 2020), and diet (Olaso-Toca et al., 1999; Cabral & Murta, 2002; Jardas et al., 2004; Šantić et al., 2005; Bahar & Tuncay, 2009; Bayhan et al., 2013; Shawket et al., 2015; Rahmani et al., 2020b). This paper focuses on the growth of the Atlantic horse mackerel, T. trachurus, living in Béni-Saf Bay (North-West Algeria), with an emphasis on the length-weight relationship and metric characters, aiming to complete the gaps in the life cycle of this Carangidae fish species and help manage this resource better in that part of the Algerian coast. MATERIAL AND METHODS A total of 355 specimens of Trachurus trachurus were collected from Béni-Saf trawl fishery, captured by trawlers operating between 30–130 m of depth (Fig. 1), from November 2016 to October 2017. The specimens sampled were subjected to biometric analysis. For each specimen, we recorded 17 meas- urements (Fig. 2). The biometric data were recorded in the laboratory, the different lengths measured using a caliper to the nearest mm, and the sex was determined macroscopically based on the morphol- ogy and the color of gonads (Rahmani et al., 2020). Sex-ratio The sex ratio is defined as the share of male or female individuals in the total number of individuals. It also gives an idea on the balance of the sexes within the population. It generally translates as the rate of femininity or masculinity in the population: SR = F / (M+F) x 100 F= number of females; M = number of males. The length-weight relationship (LWR) The Length-weight relationship (LWR) was calcu- lated from the equation: Wt = a Ltb (Korichi, 1988) where: Wt = fish body weight in grams, Lt = fish total length in centimeters, a = intercept or constant, b = slope or length exponent, and r = correlation coef- ficient. Isometric growth means that an organism’s body shape does not change as it grows, and that weight increases as the third power of length, i.e., the al- lometric parameter (b) is 3. A b < 3 value indicates negative allometric growth, which means the fish be- comes more slender as it grows longer. A b > 3 value indicates positive allometric development, which means the fish becomes stouter or deeper-bodied as it increases in weight. It should be remembered that the coefficient a is only a rough indicator of shape Fig. 1: Geographical location of the Beni-Saf Bay (we- stern coast of Algeria). Sl. 1: Zemljevid obravnavanega območja zaliva Béni-Saf (zahodna obala Alžirije). ANNALES · Ser. hist. nat. · 31 · 2021 · 1 109 Khaled RAHMANI et al.: LENGTH-WEIGHT RELATIONSHIPS AND METRIC CHARACTERS OF THE ATLANTIC HORSE MACKEREL, TRACHURUS TRACHURUS ... , 107–122 when growth is not isometric, or of shape variation when two species or sexes have different allometric parameters. The degree to which one species or sex is considered slender or stouter than another would change with length in the latter case. The a value is directly interpretable as the weight of a fish in grams when it is one centimeter in length, as measured here (Riedel et al., 2007). Metric characters To characterize the morphology of T. trachurus, the various parameters measured are expressed as a function of the total length by the following regression formula: Y = a Ltb Polynomial regression was applied to the examina- tion of morphometric relations compared to increase in total length (Kováč et al., 1999). RESULTS Sex Ratio In total, 355 specimens of Trachurus trachurus were collected, 167 males (47.04%), 159 females (44.79%), and 29 unsexed (8.17%). The length frequency dis- tribution of the entire population is shown in Fig. 3. Male length range was 9.3 to 33.5 cm; female length range 8.8 to 35.4 cm. Male weight ranged from 5.55 to 292.83 g, female weight from 5.24 to 312.78 g (Fig. 3). The variations of sex ratio according to size, veri- fied by the khi2 test, revealed significant differences Fig. 2: Morphometric measurements taken on each fish. (Lt: Total length; LF: At fork length; Ls: Standard length; Lpdo: Length pre-dorsal; Lpan: Length pre-anal; Lcep: Cephalic length; Lppc: Length pre-pectoral; Doan: Dorsal / anal distance; Doca: Dorsal / caudal distance; Lmax: Maxillary length; Dor: Diameter orbital; Pror: Length pre-orbital; Hpc: Pectoral Height; Hdo: Dorsal Height; Han: Anal Height; Hpdc: Peduncle Height; Dopc: Distance dorsal / pectoral). Sl. 2: Morfometrične meritve na vsakem primerku rib. (Lt: Skupna dolžina; LF: dolžina do vilice; Ls: standardna dolžina; Lpdo: dolžina do hrbtne plavuti; Lpan: dolžina do zadnjične plavuti; Lcep: cefalična dolžina; Lppc: dolžina do prsne plavuti; Doan: hrbtna / analna razdalja; Doca: dorzalna / kavdalna razdalja; Lmax: maksilarna dolžina; Dor: premer očesa; Pror: predorbitalna dolžina; Hpc: dolžina prsne plavuti; Hdo: dolžina baze hrbtne plavuti; Han: dolžina baze analne plavuti; Hpdc: višina pedunkla; Dopc: oddaljenost med hrbtno in prsno plavutjo). ANNALES · Ser. hist. nat. · 31 · 2021 · 1 110 Khaled RAHMANI et al.: LENGTH-WEIGHT RELATIONSHIPS AND METRIC CHARACTERS OF THE ATLANTIC HORSE MACKEREL, TRACHURUS TRACHURUS ... , 107–122 Fig. 7: Weight-length relationships for Trachurus trachu- rus (Males). Sl. 7: Odnos med maso in dolžino telesa pri samcih šnjura (Trachurus trachurus). Fig. 6: Weight-length relationships for Trachurus trachu- rus (total population). Sl. 6: Odnos med maso in dolžino telesa pri šnjuru (Tra- churus trachurus) (celotna populacija). Fig. 5: Evolution of Sex ratio by seasons of Trachurus trachurus caught in Béni-Saf Bay. Sl. 5: Sezonska dinamika spolnega deleža primerkov šnjura (Trachurus trachurus), ujetih v zalivu Béni-Saf. Fig. 4: Monthly evolution of Sex ratio of Trachurus trachurus caught in Béni-Saf Bay. Sl. 4: Mesečna dinamika spolnega deleža primer- kov šnjura (Trachurus trachurus), ujetih v zalivu Béni-Saf. Fig. 3: Length frequency distribution of Trachurus trachurus caught in Béni-Saf Bay. Sl. 3: Dolžinska razporeditev primerkov šnjura (Trachurus trachurus) ujetih v zalivu Béni-Saf. Fig. 8: Weight-length relationships for Trachurus trachu- rus (Females). Sl. 8: Odnos med maso in dolžino telesa pri samicah šnjura (Trachurus trachurus). ANNALES · Ser. hist. nat. · 31 · 2021 · 1 111 Khaled RAHMANI et al.: LENGTH-WEIGHT RELATIONSHIPS AND METRIC CHARACTERS OF THE ATLANTIC HORSE MACKEREL, TRACHURUS TRACHURUS ... , 107–122 in favor of females for length classes between 9.5 and 11 cm of TL (χ2=11 > χ2t,0.05=3.84); beyond the 16.5 cm of total length, males have the advantage, but without significance (khi2). Beyond the 34.5 cm of TL females are dominant. Monthly variations of sex ratio (Fig. 4) reveal that females dominate during the months of November, October, December, January, March, and July. Males outnumbered females during April, May, June and September, with numerical equality in August and February. Evolution of sex ratio related to seasons (Fig. 5) showed that females outnumbered males during the autumn-winter period, while males outnumbered females during the spring-summer period (χ2=5.54 > χ2t ,0.05=3.84) corresponding to the spawning period of T. trachurus in Béni-Saf Bay. The length-weight relationship (LWR) Model parameters for the Wt =f(Lt) relations of T. trachurus are given in Table 1 and Figures 6, 7, and 8. T. trachurus n Lt (min-max) Wt (min-max) a b R2 Growth total 355 7.4-35.4 3.11-312.78 0.0079 2.9981 0.9963 isometric males 167 12-33.5 5.55-292.83 0.0076 3.0168 0.9907 isometric females 158 8.7-35.4 5.24-312.78 0.0085 2.9874 0.9899 isometric Tab. 1: Estimated parameters of the weight-length relationship for Trachurus trachurus - males, females and the two sexes combined. Tab. 1: Ocenjeni parametri odnosa med maso in dolžino telesa za samce in samice šnjurov (Trachurus trachurus) ter ne glede na spol. Y=f(Lt) Equation R2 Growth Type Range Ls=f(Lt) Ls = 0.8457Lt0.9871 0.9946 Allometric (-) 7 ≤ Ls ≤ 28.6 Lpdo=f(Lt) Lpdo = 0.4268Lt0.906 0.9038 Allometric (-) 2.8 ≤ Lpdo ≤ 10.8 Lpan=f(Lt) Lpan = 0.5349Lt0.9702 0.9923 Allometric (-) 4.2 ≤ Lpan ≤ 17 Lcep=f(Lt) Lcep= 0.2684Lt0.9659 0.9836 Allometric (-) 2.1 ≤ Lcep ≤ 8.3 Lppc=f(Lt) Lppc = 0.3371Lt0.9037 0.987 Allometric (-) 2.3 ≤ Lppc ≤ 8.5 Doan=f(Lt) Doan = 0.2489Lt1.0564 0.9941 Allometric (-) 2.4 ≤ Doan ≤ 10.8 Doca=f(Lt) Doca= 0.4713Lt1.0293 0.9979 Allometric (-) 4.4 ≤ Doca ≤ 18.5 Lmax=f(Lt) Lmax = 0.1409Lt0.8626 0.9105 Allometric (-) 0.9 ≤ Lmax ≤ 3.1 Dor=f(Lt) Dor = 0.0914Lt0.8864 0.9543 Allometric (-) 0.6 ≤ Dor ≤ 2.2 LF=f(Lt) LF = 0.9841Lt0.9682 0.9949 Allometric (-) 8 ≤ LF ≤ 31.1 Pror=f(Lt) Pror = 0.0946Lt0.9802 0.9879 Allometric (-) 0.8 ≤ Pror ≤ 3.1 Hpc=f(Lt) Hpc = 0.1258Lt1.1604 0.9736 Allometric (-) 1.5 ≤ Hpc ≤ 8.2 Hdo=f(Lt) Hdo = 0.1113Lt1.0639 0.9606 Allometric (-) 1.1 ≤ Hdo ≤ 4.8 Han=f(Lt) Han = 0.1004Lt0.9856 0.9376 Allometric (-) 0.8 ≤ Han ≤ 3.6 Hpdc=f(Lt) Hpdc = 0.0301Lt1.022 0.8548 Allometric (-) 0.3 ≤ Hpdc ≤ 1.2 Dopc=f(Lt) Dopc = 0.1085Lt1.0766 0.9802 Allometric (-) 1.1 ≤ Dopc ≤ 5 Tab. 2: Correlation coefficients and regression equations of the various parameters measured as a function of total length in Trachurus trachurus (female sex, n = 158). Tab. 2: Koeficienti korelacije in regresijske enačbe raznih parametrov, povezanih s celotno dolžino pri šnjuru (Trachurus trachurus) (število samic, n = 158). ANNALES · Ser. hist. nat. · 31 · 2021 · 1 112 Khaled RAHMANI et al.: LENGTH-WEIGHT RELATIONSHIPS AND METRIC CHARACTERS OF THE ATLANTIC HORSE MACKEREL, TRACHURUS TRACHURUS ... , 107–122 The best fit was for male Trachurus (R2=0.9907) and the poorest for female Trachurus (R2=0.9899). T. trachurus presented an isometric allometry (b≈3), the weight increasing slightly less rapidly than the length. Metric characters The regression equations of observed values of all measurements are represented in Tables 2 and 3, and plotted in Figures 9, 10, 11, and 12. The proximity of observed values indicates that the regression equa- tions obtained for each of the different morphometric measurements have a good fit. Whatever the sex, all parameters show a lower growth allometry (negative allometry). The high values of correlation coefficient of all measurements with total length confirm the close coincidence be- tween them. DISCUSSION The sex ratio is slightly in favor of the males, the evolution of this index does not have phrenologi- cal regularity and is close to 1 for the March-June period, whereas females dominate in July. The Atlantic mackerel is a pelagic fish living in dense fish benches. It is possible that certain fish popula- tions display a predominance of males or females. According to Carbonara et al. (2012) and Wahbi et al. (2015), fluctuations of the sex ratio are due to ethological phenomena (stray species, demographic segregations) responsible for over-dispersion and segregated distribution of the sexes. Due to several factors, such as behavior of the species, spawning period, mortality, sampling procedure, and aggrega- tion of same sex individuals, the changes of this ratio are not readily understood. The present study shows that the values of parameter b remain close to 3 regardless of the sex, the small differences indicating that the weight increases slightly faster than the height. The size-weight relationship of T. trachurus shows isometric type allometric growth for females, males, and for the total population. The values of the coefficient of determination (R2) is close to 1, which confirms a strong correlation between the two variables (Lt, Wt). We find that our results are relatively close to those published in literature (Tab. 4): Anadon (1960) Y=f(Lt) Equation R2 Growth Type Range Ls=f(Lt) Ls = 0.9048Lt0.9612 0.9971 Allometric (-) 6.2 ≤ Ls ≤ 27.1 Lpdo=f(Lt) Lpdo = 0.4737Lt0.8658 0.9058 Allometric (-) 2.7 ≤ Lpdo ≤ 9.9 Lpan=f(Lt) Lpan = 0.5631Lt0.9524 0.9892 Allometric (-) 3.8 ≤ Lpan ≤ 16.1 Lcep=f(Lt) Lcep= 0.2819Lt0.9485 0.9806 Allometric (-) 1.9 ≤ Lcep ≤ 7.9 Lppc=f(Lt) Lppc = 0.3382Lt0.9052 0.9827 Allometric (-) 2.1 ≤ Lppc ≤ 8.1 Doan=f(Lt) Doan = 0.2922Lt1.0003 0.9903 Allometric (-) 2.2 ≤ Doan ≤ 10.1 Doca=f(Lt) Doca= 0.496Lt1.0111 0.9964 Allometric (-) 3.8 ≤ Doca ≤ 17.9 Lmax=f(Lt) Lmax = 0.0954Lt0.9909 0.9575 Allometric (-) 0.7 ≤ Lmax ≤ 3.1 Dor=f(Lt) Dor = 0.1121Lt0.8183 0.9211 Allometric (-) 0.6 ≤ Dor ≤ 2 LF=f(Lt) LF = 0.9844Lt0.9772 0.9868 Allometric (-) 7.1 ≤ LF ≤ 31.9 Pror=f(Lt) Pror = 0.1065Lt0.9286 0.9644 Allometric (-) 0.7 ≤ Pror ≤ 2.8 Hpc=f(Lt) Hpc = 0.1034Lt1.2343 0.9887 Allometric (-) 1.2 ≤ Hpc ≤ 8.1 Hdo=f(Lt) Hdo = 0.0702Lt1.2147 0.9771 Allometric (-) 0.8 ≤ Hdo ≤ 5 Han=f(Lt) Han = 0.0721Lt1.0912 0.9541 Allometric (-) 0.6 ≤ Han ≤ 3.3 Hpdc=f(Lt) Hpdc = 0.0218Lt1.138 0.9145 Allometric (-) 0.2 ≤ Hpdc ≤ 1.3 Dopc=f(Lt) Dopc = 0.099Lt1.1093 0.9841 Allometric (-) 0.9 ≤ Dopc ≤ 5.1 Tab. 3: Correlation coefficients and regression equations of the various parameters measured as a function of total length in Trachurus trachurus (male sex, n = 167). Tab. 3: Koeficienti korelacije in regresijske enačbe raznih parametrov, povezanih s celotno dolžino pri šnjuru (Trachurus trachurus) (število samcev, n = 167). ANNALES · Ser. hist. nat. · 31 · 2021 · 1 113 Khaled RAHMANI et al.: LENGTH-WEIGHT RELATIONSHIPS AND METRIC CHARACTERS OF THE ATLANTIC HORSE MACKEREL, TRACHURUS TRACHURUS ... , 107–122 Fig. 9: Relationship of total length and different morphometric indices for females Trachurus trachurus (Ls, Lpdo, Lpan, Lcep, Lppc, Doan, Doca, Lmax). Sl. 9: Odnos med celotno dolžino in različnimi morfometričnimi indeksi za samice šnjura (Trachurus trachurus) (Ls, Lpdo, Lpan, Lcep, Lppc, Doan, Doca, Lmax). ANNALES · Ser. hist. nat. · 31 · 2021 · 1 114 Khaled RAHMANI et al.: LENGTH-WEIGHT RELATIONSHIPS AND METRIC CHARACTERS OF THE ATLANTIC HORSE MACKEREL, TRACHURUS TRACHURUS ... , 107–122 Fig. 10: Relationship of total length and different morphometric indices for females Trachurus trachurus (Dor, LF, Pror, Hpc, Hdo, Han, Hpdc, Dopc). Sl. 10: Odnos med celotno dolžino in različnimi morfometričnimi indeksi za samice šnjura (Trachurus trachurus) (Dor, LF, Pror, Hpc, Hdo, Han, Hpdc, Dopc). ANNALES · Ser. hist. nat. · 31 · 2021 · 1 115 Khaled RAHMANI et al.: LENGTH-WEIGHT RELATIONSHIPS AND METRIC CHARACTERS OF THE ATLANTIC HORSE MACKEREL, TRACHURUS TRACHURUS ... , 107–122 Fig. 11: Relationship between total length and different morphometric indices in males Trachurus trachurus (Ls, Lpdo, Lpan, Lcep, Lppc, Doan, Doca, Lmax). Sl. 11: Odnos med celotno dolžino in različnimi morfometričnimi indeksi za samce šnjura (Trachurus trachurus) (Ls, Lpdo, Lpan, Lcep, Lppc, Doan, Doca, Lmax). ANNALES · Ser. hist. nat. · 31 · 2021 · 1 116 Khaled RAHMANI et al.: LENGTH-WEIGHT RELATIONSHIPS AND METRIC CHARACTERS OF THE ATLANTIC HORSE MACKEREL, TRACHURUS TRACHURUS ... , 107–122 Fig. 12: Relationship between total length and different morphometric indices in males Trachurus trachurus (Dor, LF, Pror, Hpc, Hdo, Han, Hpdc, Dopc). Sl. 12: Odnos med celotno dolžino in različnimi morfometričnimi indeksi za samce šnjura (Trachurus trachurus) (Dor, LF, Pror, Hpc, Hdo, Han, Hpdc, Dopc). ANNALES · Ser. hist. nat. · 31 · 2021 · 1 117 Khaled RAHMANI et al.: LENGTH-WEIGHT RELATIONSHIPS AND METRIC CHARACTERS OF THE ATLANTIC HORSE MACKEREL, TRACHURUS TRACHURUS ... , 107–122 for Spain, Borges and Gordo (1991), Santic (2002 and 2011) for the Adriatic. While our findings were very close to those recorded by Wengrzyn (1975) in Northwest Africa, Borges et al. (1977) in the coasts of Portugal, Kerstan (1985) in Ireland and the United Kingdom, Korichi (1988) in the Bay of Bou-Ismail, Lucio and Martin (1989) in the Bay of Biscay, Maxim (1995) in Northwest Africa, and Charef-belifa (2009) in the Bay of Oran, they do not agree with those cited by Trouvery (1977) for the Bay of Biscay, Fariña Perez (1983) for NW Spain, Arruda (reference within Gher- ram, 2019) for Portugal (Matosinhos), Itchir and Merine (2018) for the Algerian Basin, and Gherram (2019) for the Bay of Oran. The length-weight relationship parameters can vary between stocks and even between areas as mentioned by Andrade and Campos, 2002. These differences in b values can be attributed to the combination of one Author (year) Region a b Growth Anadon (1960) Espagne 0.00816 3.023 0 allometric Wengrzyn (1975) NW Afrique 0.0049 3.14 + allometric Trouvery (1977) Golf de Gascogne 0.158 1.83 - allometric Borges et al. (1977)1976 Côtes Portugaise Central Port. Côtes Portugaise 2.931 2.936 2.962 0 allometric 0 allometric 0 allometric Carrillo (1978) NW Meditérrannée 0.0102 2.945 - allometric Nazarov (1978) Gascogne 0.00585 3.087 0 allometric Farina-Pérez (1983) NW Espagne 0.01291 2.8545 - allometric Arruda (1983)a Portugal (Matosinhos) 0.0199 2.885 - allometric Arruda (1983)b Portugal (Peniche) 0.0173 2.927 0 allometric Arruda (1983)c Portugal (Portimão- Sagres) 0.0135 3.005 0 allometric Kerstan (1985) Irland et Royaum unit (Atlantique est) 0.00431 3.1251 + allometric Korichi (1988) Baie Bou-Ismail 0.0125 2.979 0 allometric Lucio & Martin (1989) Baie de Biscaye --- 3.061 0 allometric Borges & Gordo (1991) Portugal 0.009224 2.957 0 allometric Maxim (1995) NW Afrique 0.0139 2.961 0 allometric Šantić (2002) Adriatique 0.008 3.019 0 allometric Charef-Belifa (2009) Oran 0.00373 3.13 + allometric Šantić (2011) Adriatique 0.008 3.001 0 allometric Itchir & Merine (2018) Bassin algérien 0.011 2.906 - allometric Gharram (2019) Baie d’Oran (♂+♀) 0.0143 (♂) 0.0140 (♀) 0.0143 3.347 3.322 3.409 + allometric + allometric + allometric Present study Béni-Saf Bay (♂+♀) 0.0079 (♂) 0.0076 (♀) 0.0085 2.9981 3.0168 2.9874 0 allometric 0 allometric 0 allometric Tab. 4: Parameters of the height-weight relationship and weight in Trachurus trachurus obtained by various authors. Tab. 4: Parametri odnosa med masno-višinskim odnosom in maso pri šnjuru (Trachurus trachurus) na podlagi objavljenih zapisov. ANNALES · Ser. hist. nat. · 31 · 2021 · 1 118 Khaled RAHMANI et al.: LENGTH-WEIGHT RELATIONSHIPS AND METRIC CHARACTERS OF THE ATLANTIC HORSE MACKEREL, TRACHURUS TRACHURUS ... , 107–122 or more of the following factors: a) differences in the number of specimens examined, b) area/season effect, and c) differences in the observed length ranges of the specimens caught. Dulčić and Kraljević (1998) stated that temperature, food quantity, size, sex, and stage of maturity are responsible for the differences in parameters of relationship. In addition, Froese (2006) stated that small specimens have a different WLR relationship than larger ones. All the metric characters studied (17 parameters) evolve in a minor way compared to the total length, i.e., less rapidly than the total length of the fish. Only a few of the 17 measurements allow us to suggest a slightly more or less marked sexual di- morphism, which is in agreement with Geldenhuys, 1973; Macer, 1977; and Borges et al., 1977; 1991. Certain metric parameters do not develop in the same way in the two sexes. On the other hand, six (6) characters present sexual dimorphism, five (5) in favor of males (Lmax, Hpc, Hdo, Hpdc and Dopc), and one (1) in favor of females (Doan). CONCLUSIONS The results of our study on the length-weight relationships and morphometry of Trachurus trachu- rus of Béni-Saf Bay supplements the work already conducted on this species in the Mediterranean, and allows for a better management of the exploitable resource. Our findings can be a useful tool for scien- tists, administrators, and professionals in the fisher- ies sector, aiding the regulation of the fishing effort and the update of minimum landing sizes for this species. There are still many points to be elucidated in relation to the fishery of this species in the Medi- terranean Basin, and Algerian waters especially, and these will be subject of future research. ACKNOWLEDGMENTS The authors are grateful to coast guards of Béni- Saf for their precious help and also grateful to the reviewers who improved the manuscript with their helpful advices and directives. ANNALES · Ser. hist. nat. · 31 · 2021 · 1 119 Khaled RAHMANI et al.: LENGTH-WEIGHT RELATIONSHIPS AND METRIC CHARACTERS OF THE ATLANTIC HORSE MACKEREL, TRACHURUS TRACHURUS ... , 107–122 ODNOS MED DOLŽINO IN MASO IN METRIČNI ZNAKI NAVADNIH ŠNJUROV, TRACHURUS TRACHURUS (PERCIFORMES: CARANGIDAE), UJETIH V ZALIVU BÉNI-SAF, ZAHODNO SREDOZEMSKO MORJE (ALŽIRIJA) Khaled RAHMANI & Fatiha KOUDACHE University Djillali Liabes, Ecodeveloppement of spaces Laboratory, Sidi Bel Abbès 22000, Algeria e-mail: khaled46310@gmail.com Amaria Latefa BOUZIANI & Alae Eddine BELMAHI Laboratory Network for Environmental Monitoring (LRSE), Department of Biology, Faculty of Life and Nature, University of Ahmed Benbella Oran 1, BP 1524 El M’naouer, 31000 Oran, Algeria POVZETEK V pričujočem delu avtorji opisujejo morfometrične značilnosti navadnega šnjura, Trachurus trachurus (Lin- naeus, 1758), iz zaliva Béni-Saf Bay (Alžirija). Analizirali so 355 primerkov, vzorčenih med novembrom 2018 in oktobrom 2017, od katerih je bilo 47,04% samcev in 44,79% samic, 8,17% pa ni bilo določenih do spola. Celotna dolžina preiskanih rib je bila od 7,4 do 35,4 cm. Na vsakem primerku je bilo opravljenih sedemnajst meritev. Raziskali so odnos med dolžino in maso, ki je pokazal, da je porast v velikosti proporcionalen porastu v masi (izomerična alometrija). Analiza sedemnajstih metričnih znakov je omogočila ugotavljanje tipa rastne alometrije. Vsi znaki so pokazali upadajočo alometrijo, šest znakov pa je kazalo na spolno dvoličnost, od katerih se je 5 nanašalo na samce in eden na samico. Ključne besede: navadni šnjur, Trachurus trachurus, odnos med dolžino in maso, metrični znaki, zaliv Béni-Saf, Alžirija ANNALES · Ser. hist. nat. · 31 · 2021 · 1 120 Khaled RAHMANI et al.: LENGTH-WEIGHT RELATIONSHIPS AND METRIC CHARACTERS OF THE ATLANTIC HORSE MACKEREL, TRACHURUS TRACHURUS ... , 107–122 REFERENCES Abaunza, P., L. Gordo, C. 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ICES C.M. 1975/J: 19, 17 pp. ANNALES · Ser. hist. nat. · 31 · 2021 · 1 123 received: 2021-02-02 DOI 10.19233/ASHN.2021.15 ON THE OCCURRENCE OF POMADASYS INCISUS (HAEMULIDAE) IN THE TURKISH AEGEAN SEA (EASTERN MEDITERRANEAN SEA) Tülin ÇOKER Muğla Sıtkı Koçman University Faculty of Fisheries, 48000 Muğla, Turkey Okan AKYOL Ege University Faculty of Fisheries, 35440 Urla, İzmir, Turkey e-mail: okan.akyol@ege.edu.tr ABSTRACT This paper aims to complement and update the data regarding the distribution of rare Pomadasys incisus, specifically by revealing the extension of its distribution in the eastern Mediterranean Sea. On 1 November 2020, a single specimen of P. incisus was captured by an angler on a sandy/rocky bottom at a depth of 3 m in Akyaka, Gökova Bay, in the south-eastern Aegean Sea. This thermophilic fish is still very rare in the eastern Mediterranean Sea (about 142 specimens reported to date). However, it is obvious that populations of P. incisus are gradually expanding towards the northern latitudes of the eastern as well as western Mediterranean basin. Key words: Bastard grunt, additional record, measurements, Gökova Bay PRESENZA DI POMADASYS INCISUS (HAEMULIDAE) NEL MAR EGEO TURCO (MEDITERRANEO ORIENTALE) SINTESI L’articolo mira a completare e aggiornare i dati relativi alla distribuzione del pesce arabo, Pomadasys incisus, riportando l’estensione della distribuzione di questa specie nel Mediterraneo orientale. Il 1° no- vembre 2020, un singolo esemplare di P. incisus è stato catturato da un pescatore su un fondo sabbioso/ roccioso ad una profondità di 3 m, ad Akyaka, nella baia di Gökova, nel Mar Egeo sud-orientale. Questo pesce termofilo è ancora molto raro nel Mediterraneo orientale (circa 142 esemplari segnalati finora). Tuttavia, è ovvio che le popolazioni di P. incisus si stiano gradualmente espandendo verso le latitudini settentrionali del bacino orientale e occidentale del Mediterraneo. Parole chiave: pesce arabo, ritrovamento aggiuntivo, misurazioni, Baia di Gökova ANNALES · Ser. hist. nat. · 31 · 2021 · 1 124 Tülin ÇOKER & Okan AKYOL: ON THE OCCURRENCE OF POMADASYS INCISUS (HAEMULIDAE) IN THE TURKISH AEGEAN SEA (EASTERN MEDITERRANEAN SEA), 123–128 INTRODUCTION The bastard grunt, Pomadasys incisus (Bowdich, 1825), lives in coastal waters on sandy/muddy bottoms and/or close to rocky habitats as well as in sea mead- ows at depths of up to 50 m (Golani et al., 2006). Re- production occurs from July to October (Fehri-Bedoui & Gharbi, 2008). Pomadasys incisus is distributed in the eastern At- lantic coast from Madeira and Morocco, and mainly in the southern Mediterranean, but has also been reported from Seté, France, and from Italy (Ben-Tuvia & McKay, 1986; Golani et al., 2006; Froese & Pauly, 2020). The species entered the Mediterranean Sea through the Strait of Gibraltar. The prevailing cur- rents, sea warming, and the availability of suitable soft substrate in relatively shallow waters allowed this species to first establish itself in the NW Medi- terranean basin (Francour et al., 1994; Bodilis et al., 2013). While P. incisus gradually increased its abundancy in Malaga, the Catalan coast, Spain, and the Gulf of Lion, France (Serena & Silvestri, 1996; Bodilis et al., 2013; Villegas-Hernandez et al., 2018), it remains rather rare in the north-eastern Mediter- ranean Sea (Kapiris et al., 2008). This paper presents a new report of the presence of P. incisus in an area of the Aegean Sea in order to supplement the information about its distribution in the eastern Mediterranean Sea. MATERIAL AND METHODS On 1 November 2020, a single specimen of Po- madasys incisus (Fig. 1) was captured by an angler on a sandy/rocky bottom at a depth of 3 m in Akyaka, Gökova Bay (37º03.01 N - 28º19.11 E, Fig. 2) in the south-eastern Aegean Sea. The bait was bogue (Boops boops) flesh. The specimen was fixed in a 6% formaldehyde solution and deposited in the fish collection of Muğla University, Faculty of Fisheries (MUSUM/PIS/108). RESULTS AND DISCUSSION The specimen was measured to the nearest milli- metre. The morphometric measurements as percent- ages of total length (TL%) and the meristic counts recorded in the P. incisus caught in Gökova Bay, Aegean Sea, are shown in Tab. 1. All the established measurements, counts, proportions, and colour Fig. 1: Pomadasys incisus caught in Gökova Bay, SE Aegean Sea (photo: T. Çoker). Sl. 1: Primerek vrste Pomadasys incisus, ujet v zalivu Gökova, JV Egejsko morje (Foto: T. Çoker). ANNALES · Ser. hist. nat. · 31 · 2021 · 1 125 Tülin ÇOKER & Okan AKYOL: ON THE OCCURRENCE OF POMADASYS INCISUS (HAEMULIDAE) IN THE TURKISH AEGEAN SEA (EASTERN MEDITERRANEAN SEA), 123–128 patterns are in accordance with the descriptions of Ben-Tuvia & McKay (1986), Golani et al. (2006), and Froese & Pauly (2020). Pomadasys incisus is a native species of the eastern Atlantic and Mediterranean Seas. This spe- cies entered the Mediterranean Sea through the Gibraltar Strait in the early 19th century. The first report of P. incisus from the Italian seas dates to the early 1990s (Bilecenoğlu et al., 2013). The earliest report of the presence of P. incisus in the Ionian Sea was given by Kaspiris only in 1970, even though the first records for the Mediterranean waters were confirmed for the Algerian coast by Guichenot as early as 1850 and for Séte, France, by Corus in 1893 (Serena & Silvestri, 1996). After that, P. incisus was reported off the Tuscan coast in 1992 (Serena & Silvestri, 1996), and in June 2001, a specimen was caught by gillnet outside Anzio harbour in the central Tyrrhenian Sea (Psomadakis et al., 2006). Lastly, two specimens were recorded off the coast of Avola in Sicily, in the Ionian Sea, in August 2013 (Bilecenoğlu et al., 2013). On the other hand, this species seems abundant in the Gulf of Tunis (Chakroun-Marzouk & Ktari, 1995; Fehri-Bedoui & Gharbi, 2008), and between Malaga, Spain, as pointed out by Serena & Silvestri (1996), the Cata- lan coast (Villegas-Hernandez et al., 2018), and the Gulf of Lion, France (Bodilis et al., 2013). Recently, on 15 August 2015, a specimen of P. incisus was captured off the Pelješac Peninsula in the southern Adriatic Sea (Karachle et al., 2016). This was the first record for the Adriatic Sea. It clearly proves that this thermophilic species has been moving northwards, as it has so far reached the Balearic, Tyrrhenian, Ligurian and Adriatic Seas. Fig. 2: Capture location of Pomadasys incisus in the Aegean Sea. Sl. 2: Lokaliteta, kjer je bila ujeta vrsta Pomadasys incisus v Egejskem morju. Tab. 1: Morphometric measurements as percentages of total length (TL%) and meristic counts recorded in the Pomadasys incisus captured in Gökova Bay, Aegean Sea. Tab. 1: Morfometrične meritve, izražene kot delež celotne dolžine (TL%), in meristična štetja na primerku vrste Poma- dasys incisus, ujetega v zalivu Gökova, Egejsko morje. Measurements Size (mm) Proportion (TL%) Total length (TL) 169 Fork length (FL) 151 89.3 Standard length (SL) 143 84.6 Maximum body depth 51 30.2 Pectoral fin length 48 28.4 Pre-dorsal fin length 49 29.0 Pre-anal fin length 92 54.4 Pre-pectoral length 50 29.6 Head length 42 24.9 Eye diameter 13 7.7 Preorbitary length 12 7.1 Meristic counts Dorsal fin rays XII+16 Anal fin rays III+12 Pectoral fin rays 17 Ventral fin rays I+5 Weight (g) 71.8 ANNALES · Ser. hist. nat. · 31 · 2021 · 1 126 Tülin ÇOKER & Okan AKYOL: ON THE OCCURRENCE OF POMADASYS INCISUS (HAEMULIDAE) IN THE TURKISH AEGEAN SEA (EASTERN MEDITERRANEAN SEA), 123–128 In the eastern Mediterranean Sea, P. incisus has been reported sporadically, as shown in Table 2. In some previous fish checklists for the Levant Basin P. incisus was mentioned by name only, i.e., in reports from Israel (Ben-Tuvia, 1971), the eastern Levant (Golani, 1996), Mersin Bay, the NE Levant, (Gücü & Bingel, 1994), Syria (Saad, 2005), Egypt (Akel & Karachle, 2017), and the Lebanon coast (Bariche & Fricke, 2020). As it appears, this thermophilic fish is still very rare in the eastern Mediterranean Sea (about 142 specimens have been reported to date). However, it is obvious that populations of P. incisus are gradu- ally establishing themselves and expanding into the northern latitudes of the eastern and western Medi- terranean Sea (Francour et al., 1994; Serena & Sil- vestri, 1996; Bodilis et al., 2013; Villegas-Hernandez et al., 2018). According to fishermen in Gökova Bay (SE Aegean Sea), the populations of this fish species have become larger in the recent years. Francour et al., (1994) stated that captures of thermophilic spe- cies, including P. incises, have been increasing in the northern Mediterranean due to global warming. As evidence of the warming of the marine environ- ment, Azzurro (2008) provided a list of thermophilic subtropical fish species that have expanded their distribution range in the Mediterranean, which also includes P. incisus. On the other hand, since P. incisus has been ac- knowledged as an example of latitudinal extension or demographic increase of thermophilic fish in re- sponse to the current climate change (Psodomakis et al., 2012), P. incisus could be taken as an indicator of changing sea conditions due to global warming. To confirm that, however, further research is necessary which will study the overlap between exotic/thermo- philic and endemic fish fauna and their competition, e.g., between salemas and siganids, red mullets and goatfishes. ACKNOWLEDGEMENTS The authors thank angler Mr. Yusuf Geçim for his bringing the fish our attention. Tab. 2: Sporadic records of Pomadasys incisus in the eastern Mediterranean Sea. Tab. 2: Sporadični zapisi o pojavljanju vrste Pomadasys incisus v vzhodnem Sredozemskem morju. Area Date n TL (mm) Depth (m) References Iskenderun Bay, NE Mediterranean Dec.1994-Nov.1996 3 162-178 15-20 Başusta & Erdem (2000) Turkey, NE Mediterranean 2001-2003 23 119-190 5-100 Sangun et al. (2007) Gulf of Antalya, NE Mediterranean May2005-Apr.2006 23 126-182 10 Beğburs & Kebapçıoğlu (2013) Argolikos Gulf, Aegean Sea May-Aug.2008 39 ? 10-15 Kapiris et al. (2008) SE Aegean Sea Dec.2009-Nov.2010 51 121-163 30-325 Bilge et al. (2014) Morfou Bay, Cyprus 30 Sep.2019 1 ? 2 Doumpas et al. (2020) Limni Beach, Cyprus 20 May 2020 1 130 ? Doumpas et al. (2020) Gökova Bay, Aegean Sea 01 Nov.2020 1 169 3 This study ANNALES · Ser. hist. nat. · 31 · 2021 · 1 127 Tülin ÇOKER & Okan AKYOL: ON THE OCCURRENCE OF POMADASYS INCISUS (HAEMULIDAE) IN THE TURKISH AEGEAN SEA (EASTERN MEDITERRANEAN SEA), 123–128 O POJAVLJANJU VRSTE POMADASYS INCISUS (HAEMULIDAE) V TURŠKEM EGEJSKEM MORJU (VZHODNO SREDOZEMSKO MORJE) Tülin ÇOKER Muğla Sıtkı Koçman University Faculty of Fisheries, 48000 Muğla, Turkey Okan AKYOL Ege University Faculty of Fisheries, 35440 Urla, İzmir, Turkey e-mail: okan.akyol@ege.edu.tr POVZETEK Avtorja poročata o novih in dopolnjenih podatkih o razširjenosti redke vrste Pomadasys incisus, s posebnim ozirom na širjenje njenega areala v vzhodnem Sredozemskem morju. Prvega novembra 2020 je bil na trnek ujet primerek te vrste, na globini 3 m na skalnato-peščenem dnu, na lokaliteti Akyaka v zalivu Gökova v jugovzhodnem Egejskem morju. Ta toploljubna vrsta je še vedno zelo redka v vzhodnem Sredozemskem morju (do sedaj so poročali o 142 primerkih). Kakorkoli že, očitno je, da se vrsta P. incisus postopno širi proti severnim geografskim širinam tako vzhodnega kot tudi zahodnega Sredozemskega bazena. Ključne besede: vrsta prašičevke, novi zapis o pojavljanju, meritve, zaliv Gökova ANNALES · Ser. hist. nat. · 31 · 2021 · 1 128 Tülin ÇOKER & Okan AKYOL: ON THE OCCURRENCE OF POMADASYS INCISUS (HAEMULIDAE) IN THE TURKISH AEGEAN SEA (EASTERN MEDITERRANEAN SEA), 123–128 REFERENCES Azzurro, E. (2008): The advance of thermophilic fishes in the Mediterranean Sea: overview and methodological questions. In: Climate warming and related changes in Mediterranean marine biota. 27-31 May, Helgoland. CIESM Workshop Monographs, 35, 39-45. Akel Kh., S.H. & P.K. Karachle (2017): The marine ich- thyofauna of Egypt. Egypt. J. Aquat. Biol. & Fish., 21, 81-116. Bariche, M. & R. Fricke. 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ANNALES · Ser. hist. nat. · 31 · 2021 · 1 129 received: 2021-05-26 DOI 10.19233/ASHN.2021.16 FIRST SUBSTANTIATED RECORD OF OPAH, LAMPRIS GUTTATUS (OSTEICHTHYES: LAMPRIDIDAE), FROM THE TUNISIAN COAST (CENTRAL MEDITERRANEAN SEA) Sihem RAFRAFI-NOUIRA Université de Carthage, Unité de Recherches Exploitation des Milieux aquatiques, Institut Supérieur de Pêche et d’Aquaculture de Bizerte, BP 15, 7080 Menzel Jemil, Tunisia Mohamed Mourad BEN AMOR, Khadija OUNIFI-BEN AMOR & Marouène BDIOUI Institut National des Sciences et Technologies de la Mer, port de pêche, 2025 La Goulette, Tunisia Christian CAPAPÉ Laboratoire d’Ichtyologie, Université de Montpellier, case 104, 34095 Montpellier cedex 5, France e-mail: capape@univ-montp2.fr ABSTRACT The authors report on the capture of a specimen of opah, Lampris guttatus (Brünnich, 1788), from the northern coast of Tunisia. It measured 1.40 m in total length and weighed 47.65 kg, and is, probably, among the largest and the heaviest L. guttatus to date reported from the Mediterranean Sea. The species is endothermic, and thus able to live in cool waters and migrate to warmer regions. This finding represents the first record of the species for Tunisian waters and the central Mediterranean Sea. At the same time, it defines the extension of the southernmost range limit of the species in this sea. Key words: Lampris guttatus, total length, total body weight, distribution, endothermy, extension range PRIMO RITROVAMENTO DOCUMENTATO DI OPAH, LAMPRIS GUTTATUS (OSTEICHTHYES: LAMPRIDIDAE), LUNGO LA COSTA TUNISINA (MEDITERRANEO CENTRALE) SINTESI Gli autori riportano la cattura di un esemplare di opah, Lampris guttatus (Brünnich, 1788), lungo la costa set- tentrionale della Tunisia. Il pesce misurava 1,40 m di lunghezza totale e pesava 47,65 kg, ed è, probabilmente, tra i più grandi e più pesanti esemplari di L. guttatus fino ad oggi riportati per il Mediterraneo. La specie è endotermica, quindi in grado di vivere in acque fredde e migrare verso regioni più calde. Questa cattura rappresenta il primo ritrovamento della specie per le acque tunisine ed il Mediterraneo centrale. Definisce inoltre l’estensione del limite più meridionale della specie in questo mare. Parole chiave: Lampris guttatus, lunghezza totale, peso corporeo totale, distribuzione, endotermia, range di estensione ANNALES · Ser. hist. nat. · 31 · 2021 · 1 130 Sihem Rafrafi-NOUIRA et al.: FIRST SUBSTANTIATED RECORD OF OPAH, LAMPRIS GUTTATUS (OSTEICHTHYES: LAMPRIDIDAE), FROM THE TUNISIAN COAST ..., 129–136 INTRODUCTION The opah, Lampris guttatus (Brünnich, 1788), is an oceanic species distributed worldwide in tropical and temperate waters, well-known in the Atlantic and eastern Pacific (Palmer, 1986). It is a mid-water pelagic species, dwelling between 100 and 400 m of depth (Palmer, 1986). L. guttatus has also been known in the Mediterranean Sea, where it used to be considered very rare, with less than 25 specimens reported in the literature (Francour et al., 2010). However, an updated review of records from the western Mediterranean Basin now indicates that a least 23 specimens have recently been recorded in the French coast (Francour et al., 2010). L. guttatus is reported from the Adriatic Sea, where previous and recent captures of single specimens are listed by Dulčić et al. (2005) and Sulić Šprem et al. (2014). Eastward, the species is recorded in the Greek seas (Sinis, 2004) and reported in the check- list of marine fishes from Turkey (Bilecenoğlu et al., 2014). However, the first substantiated record of L. guttatus from Turkish marine waters was reported by Ergüden et al. (2019). Conversely, the species has not yet been recorded in the Levant Basin (Golani, 2005; Ali, 2018; Bariche & Fricke, 2019). Lloris & Rucabado (1998) noted the occurrence of L. guttatus in the Moroccan shore, but did not furnish any data on the capture area, Atlantic or Mediter- ranean. Similarly, no record of the species has been Fig. 1: Map of northern Tunisia with the site where Lampris guttatus was caught (black star). GH: Gulf of Hammamet. GT: Gulf of Tunis. Sl. 1: Zemljevid obravnavnega območja z označeno lokaliteto, kjer je bil ujet primerek svetlice (Lampris guttatus) (črna zvezdica). GH: zaliv Hammamet. GT: zaliv Tunis. ANNALES · Ser. hist. nat. · 31 · 2021 · 1 131 Sihem Rafrafi-NOUIRA et al.: FIRST SUBSTANTIATED RECORD OF OPAH, LAMPRIS GUTTATUS (OSTEICHTHYES: LAMPRIDIDAE), FROM THE TUNISIAN COAST ..., 129–136 provided from the Tunisian coast (Bradai et al., 2004; Rafrafi-Nouira et al., 2015; Rafarafi-Nouira, 2016; Ounifi-Ben Amor et al., 2016). To date, only one substantiated capture has been reported from the Maghreb shore. The capture occurred in the central Algerian coast (Francour et al., 2010). Regular rou- tine monitoring conducted throughout the Tunisian coast with the assistance of experienced fishermen allowed us to collect the specimen described in the present paper. MATERIAL AND METHODS On 18 May 2021, a specimen of L. guttatus was captured in the fishing area of Ghar El Melh, in Coco Beach (Fig. 1), located in northern Tunisia (37°08’58.66” N, 10°16’37.03” E), at a depth of 20 metres, on sandy bottom, together with several blotched picarel, Spicara maena (Linnaeus, 1758). It was caught by a fisherman using a small vessel and an 80 m long commercial gill with 20 mm stretched mesh size (Fig. 2). The specimen was delivered to the fish market of Ghar El Melh (Fig. 3) and rapidly sold, therefore it was only possible for us to record its total length (TL) and total body weight (TBW). RESULTS AND DISCUSSION The present specimen was identified as L. guttatus via a combination of main morphological characters: body oval, large and compressed, dorsal and anal fins long and simple, both retractable into deep grooves, first dorsal fin rays forming anterior falcate lobe; pelvic fins and dorsal fins long and falcate; anal fin long- based, without anterior lobe; caudal fin broadly lunate; back blue shading to green, belly silvery with whitish spots, fins reddish. This identification is in complete agreement with previous descriptions of L. guttatus by, among others, Palmer (1986), Dulčić et al. (2005), Francour et al., (2010), Underkoffler et al. (2018), and Ergüden et al. (2019). Therefore, the present findings constitute the Fig. 2: Lampris guttatus captured off Coco Beach, close to Ghar El Melh, aboard the small vessel. Sl. 2: Primerek svetlice (Lampris guttatus) na krovu manjšega plovila, ujet pri plaži Coco Beach, blizu Ghar El Melh. ANNALES · Ser. hist. nat. · 31 · 2021 · 1 132 Sihem Rafrafi-NOUIRA et al.: FIRST SUBSTANTIATED RECORD OF OPAH, LAMPRIS GUTTATUS (OSTEICHTHYES: LAMPRIDIDAE), FROM THE TUNISIAN COAST ..., 129–136 first substantiated record of L. guttatus from Tunisian waters. The species can be included in the list of Tunisian ichthyofauna, enlarging the number of fish species to date reported from the area (Bradai et al., 2004; Ounifi-Ben Amor et al., 2016; Rafrafi-Nouira et al., 2016). Additionally, the present constitutes the second record of the species from the southern Mediterranean Sea. The first record was made off Gouraya, from the central Algerian coast, and con- cerned a small specimen of 385 mm TL and 1.281 kg TBW (Francour et al., 2010). The specimen discussed in the present study measured 1.40 m TL and 47.65 kg in TBW (Fig. 4), ranking among the largest and heaviest L. guttatus known to date in the Mediter- ranean Sea. However, a maximum length of 2 m and a maximum weight of 270 kg have been reported by Gon (1990, in Ergüden, 2019). Tortonese (1970) noted that the species was rare in the Mediterranean Sea and only sporadically caught in Italian waters. Such observation is in congruence with the fact that L. guttatus is a rather solitary spe- cies (Palmer, 1986). Conversely, Dulčić et al. (2005) noted an increase of captures in the Adriatic Sea, and Francour et al. (2010) along the French Mediterranean coast, probably due to the warming of Mediterranean marine waters (Francour et al., 1994). The relative abundance of captures in some areas of the western Mediterranean basin suggests possible establishments of viable populations. However further records are needed for more accurate evaluations of the real status of the species in the Mediterranean Sea. L. guttatus also inhabits the cold waters of the eastern Atlantic Ocean (Palmer, 1986); such occur- rence is probably made possible by the fact that the species displays a whole-body form of endothermy (Wegner et al., 2015). Unlike other fish, in L. guttatus the warm blood is distributed throughout the body, including the heart, enhancing the animal’s physi- ological performance during foraging in cold areas (Wegner et al., 2015). Therefore, migrations from northern to southern Atlantic areas are feasible, and since these are followed by further advancement to Fig. 3: Lampris guttatus captured off Coco Beach, at the fish market of Ghar El Melh, scale bar = 300 mm. Sl. 3: Primerek svetlice (Lampris guttatus), ujet pri plaži Coco Beach, na ribji tržnici v Ghar El Melh, merilo = 300 mm. ANNALES · Ser. hist. nat. · 31 · 2021 · 1 133 Sihem Rafrafi-NOUIRA et al.: FIRST SUBSTANTIATED RECORD OF OPAH, LAMPRIS GUTTATUS (OSTEICHTHYES: LAMPRIDIDAE), FROM THE TUNISIAN COAST ..., 129–136 Fig. 4: Lampris guttatus captured off Coco Beach, at the fish market of Ghar El Melh, white arrow indicating the total body weight of the specimen, scale bar = 150 mm. Sl. 4: Primerek svetlice (Lampris guttatus), ujet pri plaži Coco Beach, na ribji tržnici v Ghar El Melh. Bela puščica označuje celokupno maso primerka, merilo = 150 mm. ANNALES · Ser. hist. nat. · 31 · 2021 · 1 134 Sihem Rafrafi-NOUIRA et al.: FIRST SUBSTANTIATED RECORD OF OPAH, LAMPRIS GUTTATUS (OSTEICHTHYES: LAMPRIDIDAE), FROM THE TUNISIAN COAST ..., 129–136 the Mediterranean Sea through the Strait of Gibraltar, we may consider L. guttatus a Herculean migrant (sensu Quignard & Tomasini, 200). It is an unusual case of migration, as generally such migrants come from the warmer waters of south-eastern Atlantic. The Tunisian coast is a transition area between the eastern and western Mediterranean Basins, and migration of alien species has frequently been reported from the same area (Rafarafi-Nouira et al., 2015, 2016; Ounifi-Ben Amor et al., 2016). The present record confirms similar previous observations; interestingly, it also constitutes the first record for the central Mediter- ranean Sea and, concomitantly, defines the extension of the southernmost range limit of L. guttatus in the wider sea. ACKNOWLEDGEMENTS The authors wish to thank M. Amor El Béji who provides them information on the specimen, and two anonymous referees for their useful comments improv- ing the scientific quality of this note. ANNALES · Ser. hist. nat. · 31 · 2021 · 1 135 Sihem Rafrafi-NOUIRA et al.: FIRST SUBSTANTIATED RECORD OF OPAH, LAMPRIS GUTTATUS (OSTEICHTHYES: LAMPRIDIDAE), FROM THE TUNISIAN COAST ..., 129–136 PRVI DOKUMENTIRAN ZAPIS O POJAVLJANJU SVETLICE, LAMPRIS GUTTATUS (OSTEICHTHYES: LAMPRIDIDAE), IZ TUNIZIJSKE OBALE (OSREDNJE SREDOZEMSKO MORJE) Sihem RAFRAFI-NOUIRA Université de Carthage, Unité de Recherches Exploitation des Milieux aquatiques, Institut Supérieur de Pêche et d’Aquaculture de Bizerte, BP 15, 7080 Menzel Jemil, Tunisia Mohamed Mourad BEN AMOR, Khadija OUNIFI-BEN AMOR & Marouène BDIOUI Institut National des Sciences et Technologies de la Mer, port de pêche, 2025 La Goulette, Tunisia Christian CAPAPÉ Laboratoire d’Ichtyologie, Université de Montpellier, case 104, 34095 Montpellier cedex 5, France e-mail: capape@univ-montp2.fr POVZETEK Avtorji poročajo o ulovu primerka svetlice, Lampris guttatus (Brünnich, 1788), iz severne tunizijske obale. Meril je 1,40 m v dolžino in tehtal 47,65 kg. Verjetno gre za enega izmed največjih in najtežjih primerkov dosedaj opaženih v Sredozemskem morju. Gre za endotermno vrsto, ki lahko naseljuje hladne vode in se seli v toplejše predele. Ta primer predstavlja prvi podatek o pojavljanju te vrste v tunizijskih vodah in v osrednjem Sredozem- skem morju, obenem pa kaže na razširjanje areala v smeri skrajne južne meje razširjenosti. Ključne besede: Lampris guttatus, celotna dolžina, celokupna masa, razširjenost, endotermija, širjenje areala ANNALES · Ser. hist. nat. · 31 · 2021 · 1 136 Sihem Rafrafi-NOUIRA et al.: FIRST SUBSTANTIATED RECORD OF OPAH, LAMPRIS GUTTATUS (OSTEICHTHYES: LAMPRIDIDAE), FROM THE TUNISIAN COAST ..., 129–136 REFERENCES Ali, M. (2018): An updated Checklist of the Marine fishes from Syria with emphasis on alien species. Medit. Mar. Sci., 19(2), 388-393. 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ANNALES · Ser. hist. nat. · 30 · 2020 · 1 137 Claudio BATTELLI & Neža GREGORIČ: FIRST REPORT OF AN AEGAGROPILOUS FORM OF RYTIPHLAEA TINCTORIA FROM THE LAGOON OF STRUNJAN ..., 61–68 FLORA FLORA FLORA ANNALES · Ser. hist. nat. · 30 · 2020 · 1 138 Claudio BATTELLI & Neža GREGORIČ: FIRST REPORT OF AN AEGAGROPILOUS FORM OF RYTIPHLAEA TINCTORIA FROM THE LAGOON OF STRUNJAN ..., 61–68 ANNALES · Ser. hist. nat. · 31 · 2021 · 1 139 received: 2021-04-20 DOI 10.19233/ASHN.2021.17 FIRST REPORT OF CYSTOSEIRA AURANTIA (SARGASSACEAE, FUCOPHYCEAE) FROM THE LAGOON OF STRUNJAN (GULF OF TRIESTE, NORTHERN ADRIATIC) Claudio BATTELLI Frane Marušič 4, 6310 Izola, Slovenia e-mail: claudio.battelli@guest.arnes.si Marcello CATRA Laboratory of Phycology, Department of Biological, Geological and Environmental Sciences, University of Catania, Via Empedocle 58, 95128 Catania, Italy e-mail: m.catra@unict.it ABSTRACT The authors report the first record of the brown alga Cystoseira aurantia Kützing, found in the Stjuža Lagoon of Strunjan (Gulf of Trieste, Slovenia). During field surveys conducted in March 2021, dense free-floating hanks of this alga were observed on the water’s surface along the eastern margins of the lagoon, at depths not exceed- ing 0.5 m. These acropleustophytic hanks were composed of abundantly branched single thalli and fragments of thalli firmly intertwined and entangled. Branches of every order were cylindrical, slender (1‒2 mm in diameter), omnidirectional, with no leafy branchlets or thorny appendages. No fertile specimens were found. Among the possible factors leading to the formation of free-floating masses of C. aurantia, mechanic processes due to a constant water movement under the action of winds and tidal currents were considered. The habitat and the morphological characters of the specimens studied are described. Key words: Cystoseira aurantia, Stjuža lagoon Strunjan, Slovenia, northern Adriatic PRIMA SEGNALAZIONE DI CYSTOSEIRA AURANTIA (SARGASSACEAE, FUCOPHYCEAE) NELLA LAGUNA DI STRUGNANO (GOLFO DI TRIESTE, ALTO ADRIATICO) SINTESI Gli autori riportano la prima segnalazione dell’alga bruna Cystoseira aurantia Kützing, trovata nella Laguna Schiusa di Strugnano (Golfo di Trieste, Slovenia). Durante le indagini sul campo, condotte nel marzo 2021, sono state osservate delle dense masse di quest’alga fluttuanti sulla superficie dell’acqua lungo il margine orientale della laguna, a profondità non superiore a 0,5 m. Le masse acropleustofitiche liberamente flottanti in superficie, si pre- sentano composte da singoli talli abbondantemente ramificati e saldamente intrecciati. Non sono stati riscontrati esemplari fertili. Tra i possibili fattori responsabili della formazione delle masse fluttuanti di C. aurantia, assume un carattere particolarmente rilevante la costante variazione delle correnti superficiali, all’interno della Laguna, dovuta alla marea. Vengono descritti l’habitat e i caratteri morfologici degli esemplari studiati. Parole chiave: Cystoseira aurantia, laguna Schiusa Strugnano, Slovenia, Alto Adriatico ANNALES · Ser. hist. nat. · 31 · 2021 · 1 140 Claudio BATTELLI & Marcello CATRA: FIRST REPORT OF CYSTOSEIRA AURANTIA (SARGASSACEAE, FUCOPHYCEAE) FROM THE LAGOON OF STRUNJAN ..., 139–146 INTRODUCTION The brown alga Cystoseira aurantia (Sargassaceae, Fucophyceae) is a perennial free-living species forming free-floating hanks. Since its description by Kützing (1843), based on specimens collected in 1835 at the Gulf of Trieste (type locality), it has been reported from both Black Sea and Mediterranean coastal areas. In the latter area, it was repor- ted from the Balearic Islands (Spain) (Ribera et al., 1996), the Adriatic Sea (Giaccone 1978; Ribera et al., 1992; Taskin et al., 2012), Corsica (France) (Taskin et al., 2012), Sardinia, Sicily, and Tuscany (Italy) (Ribera et al., 1992; Furnari et al., 1999; Rindi et al., 2002; Taskin et al., 2012), Turkey (Taskin et al., 2012), the Bay of Cadiz (Spain) (Gallardo et al., 2016), Tunisia (Bouafif et al., 2016), and more recently from the Mediterranean coast of Morocco (Ramdani et al., 2021). The species, reduced to a form of C. barbata (Stackhouse) C. Agardh [= Gongolaria barbata (Stackhouse) Kuntze] by Giaccone in Amico et al. (1986) as C. barbata f. aurantia (Kützing) Giaccone, was recently reinstated as a distinct species by Orellana et al. (2019). According to literature, C. aurantia was reported from the northern Adriatic Sea by Giaccone (1974) as C. barbata C. Agardh var. aurantia (sic!); from Ferrara by Amico et al., [1986, as C. barbata (Goodenough & Woodward) J. Agardh f. aurantia (Kützing) Giaccone]. Gómez Garreta et al. (2001) considered C. barbata f. aurantia to be synonymous with C. barbata f. repens Zinova & Kalugina, but erroneously so, since the former form takes precedence over the latter (Cormaci et al, 2012). Interestingly, there are no records of this species from the eastern Adriatic Sea (Antolić et al., 2010), except that from the Middle Adriatic Sea (the Island of Palagruža) by Giaccone (1978). In this paper, we report the occurrence of C. aurantia from the Stjuža marine lagoon of Strunjan (Slovenia). It represents the first record of this species from Slovenian coastal waters. MATERIAL AND METHODS Study area The Strunjan Lagoon is a shallow, semi-enclosed oligotro- phic brackish coastal lagoon situated in the eastern part of the Strunjan Bay (45°31’30” N, 13°36’20” E) (Figs. 1a–1b), about 10 hectares in surface area and divided into two sub-basins: a smaller discharge lagoon and the larger Stjuža Lagoon. Geologically, it represents a large area of the Late-Glacial and Holocene estuary of the Strunjan stream, formed during the last transgression of the sea into that area (Šmuc, 2020). It is the only Slovene marine lagoon, and not entirely natural. For about half a century it has been an abandoned fish farm. The newly created lagoon has remained connected with the sea only by an entrance channel of about 20 meters in width and 5‒6 meters in depth, and three much smaller tidal channels (Fig. 1b), which allow for a better circulation of water masses in the lagoon and a reduced organic pollutant load (Avčin et al., 1973; Avčin et al., 1974; Vrišer, 2002). The Stjuža Lagoon is characterised by Cymodocea nodosa (Ucria) Ascherson and Zostera noltei Hornemann meadows on its margins. It is mostly very shallow, with some of its areas breaking the surface at the lowest tide (Šajna & Kaligarič, 2005; Lipej et al., 2019). Seagrass meadows host a diverse lagoon fish fauna and demersal invertebrates (Avčin et al., 1973; Šajna & Kaligarič, 2005; Lipej et al., 2019). Fig. 1: a) Maps of the study area; b) Stjuža Lagoon of Strunjan, indicating sampling site of Cystoseira aurantia (black circles), and the direction of seawater currents during the tide (after Avčin et al., 1973). The yellow arrows indicate the output flow, the red arrows the entry flow. Sl. 1: a) Karta raziskovalnega območja; b) Laguna Stjuža Strunjan z vzorčevalnimi postajami alge Cystoseira aurantia (črni krogci), in smer toka morske vode med plimovanjem. Rumene puščice predstavljajo smer izhoda in rdeče smer vhoda morske vode med bibavico (po Avčin et al., 1973). ANNALES · Ser. hist. nat. · 31 · 2021 · 1 141 Claudio BATTELLI & Marcello CATRA: FIRST REPORT OF CYSTOSEIRA AURANTIA (SARGASSACEAE, FUCOPHYCEAE) FROM THE LAGOON OF STRUNJAN ..., 139–146 Today, the lagoon area is an important part of the Strunjan Stjuža Nature Reserve, falling within the Natura 2000 network, the primary objective of which is to pre- serve biodiversity. The study area is also characterised by the presence of a diverse fish fauna, demersal invertebrates closely associated with the environment of seagrasses: numerous molluscs (bivalves, gastropods), benthic crustaceans (mysids, amphipods, decapods, isopods), echinoderms (brittlestars, starfishes), and many species of polychaetes. Recently a total of 15 macroalgal taxa, both substrate- -attached and free-floating, were recorded (Lipej et al., 2004; 2019; Battelli & Gregorič, 2020). Environmental parameters Because of its shallow depth (only about 0.5–1 m), the thermal conditions in the Stjuža Lagoon seasonally move from one extreme to the other: ranging between 5 ºC and 10 ºC in wintertime and between 24 ºC and 27 ºC during the summer; during the other seasons the water temperatures are similar to the atmospheric temperatures. The salinity, oxygen content, and thermal conditions in the Stjuža Lagoon are related to the large water exchange and usually similar to those of Strunjan Bay (Avčin et al., 1973). The lagoon receives freshwater inputs through small canals from agri- cultural areas (Vrišer, 2002). The average tidal amplitude is 67 cm, with high tide 35 cm above mean sea level, and low tide 31 cm below mean sea level (Slovenian Environment Agency (ARSO): (www.arso.gov.si/water/sea; http://www. arso.gov.si/vode/podatki/amp/H9350_g_1.html). Sampling procedure and data analysis The fieldwork was carried out in March 2021, when dense free-floating hanks of Cystoseira aurantia were ob- served in the lagoon. The study was conducted along the eastern margins of the lagoon, as showed in Fig. 1b, since this was the only site where free-floating aggregates of the studied alga occurred in high abundance. The substrate of the research site consisted of a soft sediment composed of compact-fine argillaceous silt with a slight admixture of sand, with a thin (0.5–1 cm) yellowish brown layer of flocculent organic detritus (Vrišer, 2002; Šmuc, 2020). The salinity, pH, oxygen content (O2), and water temperature were measured in the Stjuža Lagoon and Strunjan Bay, using a Hanna HI98194 multiparameter waterproof meter. Ten thalli of C. aurantia were randomly collected during the sampling period. Fresh samples were manually collect- ed at the survey site, immediately placed in plastic bags containing water, and transported to the Laboratory of the Faculty of Mathematics, Natural Sciences and Information Technologies (FAMNIT) of Koper for further observation. Some samples were dried, pressed, and preserved in the personal herbarium of one of the authors (C.B.). The algal material collected was carefully sorted and examined using an Olympus SZ61 stereo microscope with a XC50 digital camera for morphological observation and measurements. The following measurements were carried out: thallus length from the basal part to the apex; length and diameter of main axes; length and diameter of primary axes. The occurrence of aerocysts, their length, diameter, and position, were recorded. The different positions of the conceptacles were described; in addition, the sizes of the ostioles of the conceptacles present either along the thalli or on aerocysts, were measured. The averages of all the conducted measure- ments were calculated. Species were identified based on papers by Maggs & Hommersand (1993), Bressan & Babbini (2003), Brodie et al. (2007), Sfriso (2010), Cormaci et al. (2012, 2014). The nomenclature follows Guiry & Guiry (2021). RESULTS AND DISCUSSION Samples of Cystoseira aurantia were collected in the eastern part of the Stjuža Lagoon (Fig. 1b), the only site of its occurrence. The alga was found unattached on the mobile substrate, between 0 and 0.5 m depth, forming a free-flo- ating hank of thalli of various shapes and sizes (Fig. 2a). These aggregates were composed by abundantly branched fragments of the alga, firmly intertwined and dispersedly arranged. Individual thalli in the aggregations were entan- gled with each other; consequently, branches growing in different directions (Fig. 2b) were observed within the hank. Morphological characteristics of Cystoseira aurantia The axes were cylindrical, reaching up to 20.77 cm in length, and 1.0 mm in diameter. The alga was white-brown in colour, non-iridescent; holdfast absent; primary branches cylindrical, without thorny appendages, up to 7.21 cm long and 0.9 mm in diameter; secondary branches cylindrical, without spinose appendages; ultimate branches filiform. In some thalli abundant aerocysts occurred, fairly regularly arranged on the branches, ovoid, 6.68 mm long and 1.73 mm in diameter, isolated or in short series of 2‒3 (Fig. 2c). Cryptostomata were abundant in all branches. The ostioles of the conceptacles present along the branches were fusi- form, 0.23 mm long and 0.09 mm width, with a l/w ratio of 2.64, while those on aerocysts were more ovoid, 0.22 mm long and 0.14 mm width, with a l/w ratio of 1.62 (Tab. 1). Despite the large number of conceptacles present on the thalli, the specimens examined were still infertile; in fact, we observed no sexual cells within the conceptacles. Our specimens agree well with previous descriptions and illustrations of the taxon (Cormaci et al., 2012; Bouafif et al., 2016; Ramdani et al., 2021). Algal vegetation in the Stjuža Lagoon In the Stjuža Lagoon, many algal species were present in both attached and unattached forms. C. aurantia was always present in free-floating form. It was collected mainly between ANNALES · Ser. hist. nat. · 31 · 2021 · 1 142 Claudio BATTELLI & Marcello CATRA: FIRST REPORT OF CYSTOSEIRA AURANTIA (SARGASSACEAE, FUCOPHYCEAE) FROM THE LAGOON OF STRUNJAN ..., 139–146 the water surface and 0.5 m of depth and over soft substrate. The soft bottom is clearly unsuitable for the development of a highly diverse attached macroalgal vegetation. The spatial formation of free-floating hanks of C. aurantia (Fig. 2a) was probably owed to an accumulation and aggregation of many intertwined thalli caused by winds and tidal currents flowing during the tidal switch, as illustrated in Fig. 1b, where the yellow and red arrows indicate, respectively, the outflow and inflow of seawater during the change of tides. According to Fritsch (1965) and Smith (1950), the phenomenon of the aggregation of free-floating algae can be considered the result of a dynamic action of the waves’ motion caused by winds or water currents. Pleustophyte populations, typical of lagoon enviro- nments of the Mediterranean Sea, are mainly characterised by Valonia aegagropila C. Agardh, Rytiphlaea tinctoria (Clemente) C. Agardh, Lychaete echinus (Biasoletto) Wynne, and Chaetomorpha linum (O.F. Müller) Kützing (Calvo et al., 1980; Orestano & Calvo, 1985; Cecere et al., 1992). The most abundant unattached algal species found in the Stjuža Lagoon were green algae of the genus Ulva, U. rigida C. Agardh, and U. australis Areschoug. Together with Enteromorpha-type forms of Ulva (U. compressa Linnaeus and U. intestinalis Linnaeus), Chaetomorpha linum (O.F. Müller) Kützing, Lychaete echinus, Cladophora lehmanni- ana (Lindenberg) Kützing, and C. liniformis Kützing, they formed mostly unattached aggregates. Some red algae, such as Ceramium sp., Polysiphonia sp., and Polysiphonia spinosa (C. Agardh) J. Agardh, were also present. The long thallus in the free-floating form of C. aurantia facilitates the formation of dense aggregations and consequently the colonisation of the lagoon habitat. Some species of macroalgae were found as epiphytes on the thalli of C. aurantia, but they were very rare. Among them we observed Ceramium spp., Titanoderma pustulatum (J.V. Lamouroux) Näegeli, Cladophora spp, and Cladosiphon zosterae (J. Agardh) Kjlin. We did not observe any species of invertebrates within C. aurantia free-floating hanks, except for a single occurrence of Asterina gibbosa (Pennant, 1777). Water quality of the Stjuža Lagoon of Strunjan Judging from the information available for other parts of the Mediterranean, we believe that certain environmental conditions characteristic of the Stjuža Lagoon favour the formation of free-floating forms of C. aurantia, namely: (i) shallowness (an average depth of about 0.5–1 m), which allows for continuous exposure to sunlight and, consequently, the growth of algal thalli in all directions; (ii) superficial and bottom water cur- rents produced by winds blowing from the North-North- -East (bora) and from the South-East (sirocco); (iii) a wide tidal range of about 67 cm; and (iv) a soft sedimentary bottom unfavourable to the development of attached macroalgae. During the sampling period, the values of salinity, temperature, and pH of the sampling site were very simi- lar to those of the open sea (Strunjan Bay), while greater differences were observed when comparing the oxygen values of the sampling site (9.98 ppm) with those of the waters of the Strunjan Bay (12.08 ppm) (Tab. 2). The results obtained from our measurements are prevalently in agreement with those obtained in previous studies (Avčin et al., 1873; Vrišer, 2002; Lipej et al., 2019). C. aurantia clearly thrives as the lagoon ecosystem conditions improve, possibly because of its sensitivity to water quality and the hydrodynamic environment. The eastern part of the Stjuža Lagoon, where that alga is most common, is probably least exposed to less favourable environmental conditions and displaying conditions very similar to those of the water of Strunjan Bay (Tab. 2). The connections with the sea through the entrance and the tidal channels, favouring water circulation, have probably facilitated the colonisation and spread of C. aurantia. Also, since this alga is unattached, water circulation patterns in the lagoon undoubtedly influence its distribution towards the eastern part of the Stjuža Lagoon. On the other hand, the sea connections ensure a better circulation of water masses in the lagoon and reduced organic pollution. Fig. 2: a) Free-floating hanks of alga in the natural habitat; b) habit of Cystoseira aurantia; c) aerocysts isolated and in short series, indicated by arrows. Sl. 2: a) Prosto plavajoči skupki alge v naravnem okolju); b) steljka alge Cystoseira aurantia; c) posamezne aerociste in v zaporedju, označene s puščicami. ANNALES · Ser. hist. nat. · 31 · 2021 · 1 143 Claudio BATTELLI & Marcello CATRA: FIRST REPORT OF CYSTOSEIRA AURANTIA (SARGASSACEAE, FUCOPHYCEAE) FROM THE LAGOON OF STRUNJAN ..., 139–146 Impact on the environment Information on the presence in the Stjuža Lagoon of brown algae, which indicates a good status of water, are very scarce. From literature data, a total of 15 macroalgal taxa, attached and free-floating, were recorded in the lagoon (Lipej et al., 2004, 2019; Battelli & Gregorič, 2020). Most of the macroalgal species found by Lipej et al. (2019) are ESG II class (Orfanidis et al., 2011) and as such not indicative of good ecological status. From papers in Lipej et al. (2004) and Lipej et al. (2019) it results that brown algae Cystoseira com- pressa (Esper) Gerloff & Nizamuddin and Fucus virsoides J. Agardh, both indicators of good ecological status, were at times present in the Stjuža Lagoon, but we did not encounter those species during our study. It is interesting to note that F. virsoides disappeared from the entire Slovenian coast a few years ago due to reasons still unknown (Battelli, 2016). Or- lando-Bonaca & Rotter (2018) observed a certain regression of Cystoseira species in recent years in the coastal waters of Slovenia. Recently, Battelli and Gregorič (2020) reported the occurrence of Cystoseira foeniculacea (Linnaeus) Greville f. tenuiramosa (Ercegović) Gómez Garreta, Barceló, Ribera et Rull Lluch in the lagoon, attached to hard substrata and as epiphyte on a ball-like form of Rytiphlaea tinctoria, which is certainly evidence to the species diversity of the lagoon. Unfortunately, up to now, there have been no studies about the ecological conditions that could somehow expla- in the occurrence of C. aurantia in the lagoon. Further inve- stigation regarding the causes that have led to the presence of only two species of Cystoseira is desirable and necessary. The present observations were limited to a single sam- pling period. Unfortunately, we did not have additional data on the environmental conditions that may have favoured the unusual formation of the free-floating form of this brown alga in the Stjuža Lagoon of Strunjan. Our assumptions are based exclusively on the observations made during the short research period and the study of the available literature. It is therefore evident that further investigations, repeated in time, will be necessary for a deeper understanding of this phenomenon. CONCLUSIONS On the basis of the cited literature and observations made during this study, we suppose that the formation of the free-floating forms of the unattached brown alga Cystoseira aurantia in the Stjuža Lagoon of Strunjan may be a consequence of (i) mechanic processes due to a consistent movement of water under the action of winds and tidal currents between high and low tides, and (ii) characteristics intrinsic to the species which allow the growth of the thallus in any direction and thereby an ever-changing exposure to light. ACKNOWLEDGEMENTS We would like to thank several individuals who helped with the present study. We are particularly grateful to the director and the staff of Public Institute Landscape Park Strunjan (Slovenia), for allowing us to carry out the research. To Bojana Lipej from Škocjanski zatok Nature Reserve, who helped us during the measurements of physical and chemical parameters of the Lagoon. Special thanks to Pro- fessor Giovanni Furnari from the Laboratory of Phycology, Department of Biological, Geological and Environmental Sciences, University of Catania, whose valuable suggestions made a substantial contribution to the manuscript. Tab. 1: Average values of some morphological measurements of brown alga Cystoseira aurantia from the Stjuža Lagoon of Strunjan. Tab. 1: Povprečne vrednosti nekaterih morfoloških meritev pri rjavi algi Cystosera aurantia iz Lagune Stjuža v Strunjanu. Thallus Primary branches Aerocysts Ostioles of conceptacles along the branches Ostioles of conceptacles on aerocysts length/ cm diam./ mm length/ cm diam./ mm length/ cm diam./ mm length/ cm diam./ mm ratio l/w length/ cm diam./ mm ratio l/w mean 20.77 1.00 7.21 0.90 6.68 1.73 0.23 0.09 2.64 0.22 0.14 1.62 stdev 7.46 0.11 2.59 0.13 0.96 0.18 0.02 0.02 0,55 0.02 0.01 0.25 Tab. 2: Comparisons among the values of salinity, tempe- rature, pH and oxygen recorded at the sampling site and in Strunjan Bay during the sampling period (March 2021). Tab. 2: Primerjava vrednosti slanosti, temperature, pH in kisika na vzorčevalni postaji in v Strunjanskem zalivu, v obdobju vzorčenja (marec 2021). Location salinity T (°C) pH O2 (ppm) Stjuža lagoon 34.00 19.64 7.87 9.98 Strunjan bay 34.46 15.05 8.25 12.08 ANNALES · Ser. hist. nat. · 31 · 2021 · 1 144 Claudio BATTELLI & Marcello CATRA: FIRST REPORT OF CYSTOSEIRA AURANTIA (SARGASSACEAE, FUCOPHYCEAE) FROM THE LAGOON OF STRUNJAN ..., 139–146 PRVO POROČILO O VRSTI CYSTOSEIRA AURANTIA (SARGASSACEAE, FUCOPHYCEAE) V STRUNJANSKI LAGUNI (TRŽAŠKI ZALIV, SEVERNI JADRAN) Claudio BATTELLI Frane Marušič 4, 6310 Izola, Slovenia e-mail: claudio.battelli@guest.arnes.si Marcello CATRA Laboratory of Phycology, Department of Biological, Geological and Environmental Sciences, University of Catania, Via Empedocle 58, 95128 Catania, Italy e-mail: m.catra@unict.it POVZETEK Avtorja poročata o pojavu rjave alge Cystoseira aurantia iz morske lagune Stjuža v Strunjanu (Tržaški zaliv, severni Jadran), ki predstavlja prvi zapis o tej vrsti v obalnem morju Slovenije. Študija je bila izvedena marca 2021, na vzhodnem delu lagune, kjer je bila ugotovljena večja gostota prosto plavajočih prepletenih mas te alge, na globini, ki ni presegala 0,5 m. Opisani so življenjski prostor, morfološki znaki preučenih vzorcev. Ugotovljeno je bilo, da je mehko dno lagune očitno ugodno za razvoj nepritrjene vegetacije alg, katerih predstavnik je C. aurantia. Avtorja domnevata, da je nastanek prosto plavajočih mas te alge v Strunjanski laguni Stjuža mogoče razlagati kot posledico dinamičnega delovanja valov zaradi vetrov in plimskih tokov ter kot rezultat aktivne vloge alge, ki omogočajo rast steljke v vse smeri, saj nima pritrdilnih struktur, in s tem nenehno spreminja izpostavljenost svetlobi. 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(2002): The meiofauna of two protected wetlands on the Slovene coast: the Škocjan inlet and the Strunjan Lagoon. Annales Ser. Hist. Nat., 12(2), 203-210. ANNALES · Ser. hist. nat. · 31 · 2021 · 1 147 received: 2020-12-05 DOI 10.19233/ASHN.2021.18 LE ORCHIDACEAE DI PINGUENTE (BUZET) Amelio PEZZETTA Via Monte Peralba 34 - 34149 Trieste e-mail: fonterossi@libero.it SINTESI Pinguente (Buzet, Croazia) è situato nell’Istria nord occidentale. Il territorio si estende su una superficie di circa 167 km2. Il presente lavoro, basato su osservazioni dirette, una ricerca bibliografica e segnalazioni inedite, riporta una check-list aggiornata di tutte le Orchidaceae presenti in tale territorio che comprende 41 taxa specifici e infraspecifici e 3 ibridi. Inoltre è stata eseguita l’analisi corologica di questa florula da cui risulta la prevalenza dell’elemento Mediterraneo seguito da quello Eurasiatico. Parole chiave: Pinguente, Buzet, Orchidaceae, check-list, spettro corologico THE ORCHIDACEAE OF BUZET (HR) ABSTRACT Buzet (HR) is located in north-western Istria and its territory covers an area of ca 167 km2. This work, based on direct study in the field, on a bibliographic research and unpublished reports presents an updated check-list of all Orchidaceae including 41 specific and infraspecific taxa and 3 hybrids. Furthermore, a chorological analysis of this florula was carried out: it highlights the prevalence of the Mediterranean element followed by the Eurasian. Key words: Pinguente, Buzet, Orchidaceae, check-list, chorological spectrum ANNALES · Ser. hist. nat. · 31 · 2021 · 1 148 Amelio PEZZETTA: LE ORCHIDACEAE DI PINGUENTE (BUZET), 147–156 INTRODUZIONE La famiglia delle Orchidaceae Juss. è costituita da circa 27.800 specie ripartite in 880 generi (Givnish et al., 2016) e, dopo le Asteraceae Mar- tinov, è la più ricca del mondo vegetale. Essa, pur raggiungendo la maggiore abbondanza e diversità nelle zone tropicali, ha colonizzato con successo quasi ogni bioma terrestre. In Europa e nel bacino del Mediterraneo sono segnalati oltre 600 taxa (Delforge, 2016); nella Repubblica di Croazia ne sono segnalati 181 (Nikolić, 2015) mentre nella penisola istriana 82 (Pezzetta, 2018a). Tale fami- glia suscita un notevole fascino per cui numerosi gruppi, associazioni e o semplici appassionati le studiano, coltivano e ricercano. Il presente stu- dio, in linea con tale tendenza, ha per finalità la compilazione di una check-list comprendente le specie, le sottospecie e gli ibridi di orchidacee presenti nel Comune di Pinguente per il quale sinora non è stato pubblicato nessun lavoro spe- cifico su tale argomento. Inquadramento dell’area d’indagine Il Comune di Pinguente (in croato Buzet) è situato nell’Istria nord-occidentale, tra la Re- pubblica di Slovenia e la valle del fiume Quieto. Confina con i Comuni di Portole-Oprtalj a ovest; Capodistria-Koper (Repubblica di Slovenia) a nord-ovest, Lanischie (Lanišće) a nord-est, Lu- pogliano (Lupoglav) ad est; Montona-Motovun, Cerreto (Cerovlje) e Pisino (Pazin) a sud. Il territorio comunale nei suoi confini attuali occupa una superficie di 167 km²; è situato in una fascia altitudinale che va da circa16 metri s.l.m. nella valle del Quieto a oltre 500 metri s.l.m. del ciglione carsico; è costituito da colline, aree più o meno pianeggianti e valli di diverso aspetto e composizione rocciosa che contribuiscono a formare un paesaggio morfologicamente molto differenziato. La sua popolazione complessiva è di oltre 6200 abitanti sparsi in 71 insediamenti, mentre la densità media è di 37,2 abitanti per km². Il centro cittadino di Pinguente, d’origine medioevale, è situato sulla cima di una collina alta 158 metri s.l.m che s’innalza isolata in una valle delimitata nella sua parte settentrionale dal ciglione carsico della Cicceria (Ćićarija), una subregione montuosa dell’Istria nord-orientale. Il territorio pinguentino fu abitato fin dall’epo- ca preistorica e durante l’età del Bronzo, popo- lazioni di origine illirica si stabilirono nell’area costruendo insediamenti collinari circondati da mura (Alberi, 1997). Il corso d’acqua più importante che attraversa l’ambito di studio è il Quieto (in croato Mirna), dalla lunghezza totale di circa 53 km. L’area è attraversata anche da altri brevi corsi d’acqua talvolta occasionali che affluiscono nel Quieto o che, a contatto con le rocce calcaree s’infiltrano nel sottosuolo: Draga (Pivka), Rečina, Bulaž, Butoniga, Bračana, Sušak, Gregorički potok, Senjski potok, Senica, etc. (Prostorni plan Grada Buzeta, 2005). Nel terri torio pinguentino è presente anche un lago arti f iciale ottenuto dallo sbarramento del Butoniga, i l più importante aff luente del Quieto. La geologia L’area di studio è caratterizzata da terreni che derivano da rocce di origine sedimentaria: rocce calcaree, rocce marnoso-arenacee e depositi al- luvionali del Quaternario presenti nelle valli del Quieto, del Brazzana (Bračana) e del Bottonega (Butoniga). I sedimenti più antichi iniziarono a depositarsi durante il Cretaceo Superiore e conti- nuarono nelle epoche successive (Pleničar et al., 1969, 1973; Šikić et al., 1972; D’Ambrosi, 1976; Forti, 1996; Alberi, 1997; Perković, 2017). Le principali aree con rocce calcaree sono pre- senti nella Cicceria, a sud-est di Pinguente tra i torrenti Rečina e Draga, presso Kuk, Ročko polje, il canyon del fiume Quieto tra le Porte di Ferro (Kameni Vrata) e Bagni di Santo Stefano (Istarske Toplice) e, tra Brnobić e la sorgente di San Gio- vanni (Sv. Ivan). A causa della natura permeabile del terreno in tali ambiti non sono presenti corsi d’acqua superficiali. Le aree marnoso-arenacee a loro volta sono presenti nel resto del territorio. Essendo im- permeabili, su di esse riaffiorano le sorgenti e scorrono i corsi d’acqua. Tali ambiti sono caratte- rizzati da varie colline che si elevano più o meno dolcemente dal fondovalle e raggiungono quote comprese tra 200 e 454 metri. Lungo il letto del Quieto, Brazzana (Bračana), Bottonega (Butoniga) e altri torrenti si rinvengono depositi alluvionali con argille, sabbie ed altri materiali. Il clima Il clima del pinguentino è condizionato dalla sua morfologia territoriale e dalla sua posizione nell’entroterra istriano. In particolare la sua conformazione favorisce sia la penetrazione della bora che accentua la continentalizzazione climatica, sia quella delle correnti d’aria calda attraverso la valle del Quieto che, a loro volta favoriscono l’espansione del clima mediterraneo nelle zone interne della penisola istriana. ANNALES · Ser. hist. nat. · 31 · 2021 · 1 149 Amelio PEZZETTA: LE ORCHIDACEAE DI PINGUENTE (BUZET), 147–156 Nell’area di studio, quindi, variando l’esposi- zione ai venti e alle correnti d’aria si possono originare diversi microclimi locali. In particolare, il Piano Regolatore della Città di Buzet (Prostorni Plan Grada Buzeta, 2005) individua due partico- lari tipologie climatiche. La prima, definita “temperato calda”, copre l’area con altitudine inferiore a 500 metri ed è caratterizzata dai seguenti parametri: temperatura media mensile del mese più caldo superiore a 22 °C: precipitazioni con un massimo principale in autunno (ottobre o novembre) e uno secondario tra maggio e giugno; temperatura media annua registrata a Pinguente di 12.8 °C; temperature massima assoluta +38,6 °C e minima assoluta -14,1 °C (Tomić, 1981). La seconda tipologia climatica comprende la zona pedemontana e montana posta oltre 500 m. Le sue caratteristiche principali, secondo il Prostorni Plan sono: estati fresche con tempera- tura media del mese più caldo inferiore a 22 °C e precipitazioni con distribuzione mensile più uniforme. I modelli di classificazione di Köppen (1936) e Šegota & Filipić (2003) applicati all’ambito di studio confermano l’esistenza di due tipologie climatica e precisano che: • l’area della valle del Quieto in cui si sviluppa la foresta di Montona, rientra nel tipo clima- tico caldo-umido temperato senza stagione secca che è definito “Cfa” ed è caratterizzato dalla temperatura media del mese più caldo che supera 22 °C e le precipitazioni annue comprese tra 700 mm e 1500 mm; • le colline circostanti sono caratterizzate da un clima più fresco che rientra nel tipo “Cfb”, a sua volta caratterizzato dalla temperatura media della stagione estiva inferiore a 22 °C. Aspetti floristici, vegetazionali e fitogeografici Nell’area in esame, le varietà paesaggistiche, la bassa densità di popolazione, l’andamento climatico e la pressione antropica attuale e del passato hanno creato le premesse per lo sviluppo di formazioni vegetali molto varie. Infatti, il pin- guentino si può considerare un grande mosaico caratterizzato da piccoli centri abitati, infrastrut- ture stradali, aree coltivate, zone umide, boschi di varie tipologie, aree incolte, prati-pascolo e pinete artificiali. Gli ambiti boschivi della zona occupano circa 7.335 ha (Prostorni Plan Grada Buzeta 2005), un dato corrispondente a oltre la metà della superfi- cie indagata. Attualmente essi sono in espansione sui terreni e pascoli abbandonati. Le principali tipologie vegetali presenti nell’a- rea di studio sono le seguenti: • radure prative e prati-pascolo secondari inquadrabili in diverse associazioni vegetali in cui generalmente si rinvengono Carex humilis Leys, Centaurea rupestris L., C. wel- deniana Rchb., Chryspogon grillus (L.) Trin., Crocus reticulatus Stev ex Adam, Euphorbia nicaensis All., Danthonia alpina Vest., Dian- thus sylvestris Wulfen subsp. tergestinus (Rchb.) Hayek, Fritillaria orientalis J.M.F. Adams, Lathyrus pannonicus (Jacq.) Garcke, Lotus corniculatus L., Narcissus radiiflorus R.A. Sal., Onosma javorkae Simk., Planta- go media L., Polygala nicaeeensis Risso ex W.D.J. Koch, Pulsatilla montana (Hoppe) Reich. subsp. montana, Salvia pratensis L., Scorzonera villosa Scop., Linum narbonense L. ed altre entità; • associazioni sinantropiche con composizioni floristiche molto variabili che attecchiscono presso i centri abitati, le abitazioni sparse, i bordi stradali, i campi coltivati e i terreni incolti; • arbusteti e formazioni arboreo-arbustive in fase di espansione sui pascoli e terreni abbandonati, alla cui composizione general- mente concorrono Carpinus orientalis Mill., Cornus mas L., Cornus sanguínea L., Cotinus coggygria Scop., Crataegus monogyna Jacq., Juniperus communis L., Ligustrum vulgare L, Paliurus spina-christi Mill., Rosa canina L, Spartium junceum L., etc.; • lembi di bosco submediterraneo (anch’essi in fase di espansione), presenti sia sui terreni marnoso-arenacei sia su quelli calcarei com- posti dalle seguenti essenze arboree: Acer monspessulanus, A. campestre L., Fraxinus ornus L., Ostrya carpinifolia Scop., Quercus pubescens Willd. • associazioni erbacee, prative, arboreo-ar- bustive e forestali rinvenibili presso i corsi d’acqua ed altri ambienti umidi con Alisma plantago-aquatica L., Baldellia ranunculoi- des (L.) Parl, Equisetum arvense L., Frangula alnus Mill., Gentiana pneumonanthe L., Lemna gibba L, Phragmites communis Trin., Ranunculus lingua L., Symphytum officinale L., Stachys palustris L., varie specie di carici, giunchi, salici ed altre entità; • lembi di castagneto presenti nella valle del Quieto presso Zrenje, nella valle del Bottonega e in altre località (Galant, 2017) composti da Acer obtusatum W. & K, ex Willd., Castanea sativa Mill., Fraxinus ornus, Helleborus multifidus Vis., Quercus cerris L., ANNALES · Ser. hist. nat. · 31 · 2021 · 1 150 Amelio PEZZETTA: LE ORCHIDACEAE DI PINGUENTE (BUZET), 147–156 Sesleria autumnalis (Scop.) F.W. Schultz, ed altro; • lembi dal bosco misto mediterraneo (Or- no-Quercetum-ilicis Horvatić) presenti nei pressi di Istarke Toplice e in altri ambiti esposti a sud-ovest e molto riparati dalla bora (Galant, 2017) con Asparagus acuti- folius L., Fraxinus ornus, Laurus nobilis L., Quercus ilex L. Phyllirea latifolia L., Pistacia terebinthus L., etc.; • boschi artificiali di pino nero (Pinus nigra J.F. Arnold) presenti in varie località; • formazioni t ipiche di ambienti rocciosi presenti presso il ciglione carsico, tra Kameni Vrata e Istarske Toplice ed altre località ove nel complesso si r invengono Arabis hirsuta (L.) Scop., Asperula arista- ta Linnaeus f. subsp. oreophila (Briquet) Hayek, Asplenium ceterach L., Campanula pyramidalis L. , Euphorbia fragifera Jan, Moehringia tommasini i Marchesetti , Salvia off icinal is L., Sedum dasyphyllum L., S . sexangulare L., Stipa eriocaulis Borb. ed altre entità. Nel territorio di Pinguente, in particolare tra Istarke Toplice e la valle del Bottonega si svilup- pa un lembo del cosiddetto “bosco di S. Marco o di Montona”, un importante gioiello naturali- stico noto anche per le sue essenze tartutifere e protetto dalla Repubblica di Venezia sino al 1797, quando l’Istria era sotto la sua sovranità. Si tratta di un esempio di bosco planiziale che un tempo era molto diffuso lungo le pianure alluvionali europee che oggi è conservato solo in poche aree risparmiate dall’espansione dei terreni coltivati, delle aree urbane e delle infra- strutture di trasporto. I l complesso forestale recentemente è stato oggetto di molti studi f loro-vegetazionali (Ber- tović, 1975; Korijan, 2016; Vukelić et al . , 2018) in cui si dimostra che alla sua composizione concorrono associazioni vegetali azonali e rare per la penisola istriana. Infatt i , Korijan (2016), segnala nella foresta di Montona le seguenti associazioni vegetali : Leucojo aesti - vi-Fraxinetum angusti fol iae Glavač 1959, Pruno padi-Fraxinetum angusti fol iae Glavač 1960, Genisto elatae-Quercetum roboris Horvat 1938, Fraxino angusti fol iae-Ulmetum laevis Slavinić 1952 e Carpino betul i -Quercetum roboris (Anić 1959) Rauš 1971. Le principali essenze arboree presenti nelle aree più umide del bosco sono: Carpinus betulus L., Fraxinus angusti fol ia Vahl, F. excelsior L., Prunus padus L., Quercus robur L., Ulmus laevis Pall. e U . minor Mill (Vukelić et al. , 2018). Al generale corteggio floristico del pinguenti- no concorrono anche le orchidacee che in seguito saranno analizzate e discusse. MATERIALI E METODI L’elenco floristico è stato realizzato tenendo conto delle ricerche sul campo dell’autore e dei dati ricavati dalle consultazioni bibliografiche. Esso comprende le specie, le sottospecie e gli ibridi mentre non sono state prese in considera- zione le varietà cromatiche e morfologiche. Le prime estemporanee e personali osservazio- ni nell’area iniziarono circa una decina di anni fa e si sono protratte con cadenze più o meno settimanali sino al 2019. Nel 2020 a causa della pandemia si sono interrotte. Accanto ad ogni taxon sono riportati: il tipo corologico, gli autori che l’hanno segnalato, le località di presenza in lingua croata e le eventuali osservazioni sul rango tassonomico. Per la nomenclatura si è seguita quella adottata nel recente volume del GIROS (2016) mentre per le specie non riportate in tale testo Delforge (2016). In diversi casi, alla nomenclatura sono aggiunte varie precisazioni riportate nelle osservazioni. Per l’assegnazione dei tipi corologici si è tenu- to conto di quanto riportato in: Delforge (2016), Pignatti (2017) e Pezzetta (2018b). Sono riportate nel testo anche le segnalazioni di orchidacee che nel sito internet “Flora Croatica” di Nikolić (2015) ricadono all’interno dei confini del territorio appartenente alla città di Pinguente. Nell’elenco floristico per ogni taxon sono ri- portati tutti i siti di ritrovamento seguiti dal punto esclamativo per indicare le osservazioni persona- li e da sigle costituite da lettere maiuscole che si riferiscono agli autori delle segnalazioni. Esse hanno il seguente significato: AX: Teschner (1987); BX: Starmühler (2000); CX: Biel (2001); DX: Hertel S. & K., (2002); EX: Romolini (2002); FX: Šmitȧk (2002); GX: Kranjčev (2005); HX: Nikolić (2015); IX: Nikolić & Topić (2005); LX: Delforge (2006); MX: Starmühler, (2007); NX: Griebl (2009); OX: Starmühler (2010); PX: Grabner & Grabner (2013); PY: Rottensteiner (2014); QX: Rottensteiner (2015); QY: Tout & Harmes (2018): QY: Rottensteiner (2018); RX: Rottensteiner (2019); SX: John e Gerry’s (2018). RISULTATI E DISCUSSIONE Elenco floristico 1. Anacamptis coriophora (L.) R.M. Bateman, Pridgeon & M.W. Chase subsp. coriophora – Eurimediterraneo. (NX). Vrh. ANNALES · Ser. hist. nat. · 31 · 2021 · 1 151 Amelio PEZZETTA: LE ORCHIDACEAE DI PINGUENTE (BUZET), 147–156 2. Anacamptis coriophora (L.) R.M. Bateman, Pridgeon & M.W. Chase subsp. fragrans (Pollini) R.M. Bateman, Pridgeon & M.W. Chase – Eurimediterraneo. (DX, FX, GX, HX, NX, PX, SX). Bartolići!, Barušići, Buzet, Krti!, Krušvari!, Penićiće!, Sv. Donat!, Svi Sveti!, Vrh. 3. Anacamptis laxiflora (Lam.) R.M. Bateman, Pridgeon & M.W. Chase – Eurimediterraneo. (CX, EX, FX, GX, PX). Barušići!, Bračana, Buzet, Hum, Krti!, Veli Mlun! 4. Anacamptis morio subsp. morio (L.) R.M. Bateman, Pridgeon & M.W. Chase – Europe- o-Caucasico. (CX, DX, GX, HX, NX, PX, QY). Bartolići!, Barušići, Buzet!, Erkovčići!, Gor- nja Nugla!, Hum!, Krti!, Marinci!, Prodani!, Ročko Polje!, Sv. Donat!, Svi Sveti!, Žonti! 5. Anacamptis papilionacea (L.) R.M. Bateman, Pridgeon & M.W. Chase – Eurimediterraneo. (HX). Krti. 6. Anacamptis pyramidalis (L.) Rich. subsp. pyramidalis – Eurimediterraneo. (CX, DX, FX, GX, HX, LX, NX, OX, PX, QX). Bartolići!, Barušići, Bračana!, Buzet, Gornja Nugla!, Hum!, Krti!, Krušvari!, Marinci!, Prodani!, Roč, Ročko Polje!, Sv. Donat!, Svi Sveti!, Štrped, Veli Mlun!, Vrh. 7. Cephalanthera damasonium (Mill.) Druce – Eurimediterraneo. (CX, HX, NX). Barušići, Buzet!, Erkovčići, Hum!, Krušvari!, Sv. Do- nat! 8. Cephalanthera longifolia (L.) Fritsch – Eura- siatico. (CX, DX, FX, GX, HX, PX). Bartolići!, Barušići, Butoniga. Buzet!, Hum!, Krti!, Marinci!, Prodani!, Svi Sveti!, Vrh! 9. Coeloglossum viride (L.) Hartm. – Circumbo- reale. (GX). Buzet, Hum. 10. Dactylorhiza incarnata (L.) Soó – Eurosibe- riano. (CX, EX). Buzet, Krti, Veli Mlun! 11. Dactylorhiza maculata (L.) Soó subsp. fuchsii (Druce) Hyl . – Eurasiatico. (HX). Bračana! 12. Dactylorhiza sambucina (L.) Soó – Europeo. (NX). Buzet. 13. Epipactis atrorubens (Hoffm.) Besser – Euro- peo. (PX). Sv. Donat! 14. Epipactis helleborine subsp. helleborine (L.) Crantz – Paleotemperato. (DX, HX, PX). Bračana!, Buzet, Hum, Ročko Polje!, Sv. Donat. 15. Epipactis microphylla (Ehrh.) Sw. – Europe- o-Caucasico. (PX, SX). Sv. Donat. 16. Epipactis muelleri Godfery – Centro-Euro- peo. (CX, DX, FX, PX). Bračana!, Buzet!, Krti, Prodani!, Sv. Donat, Vrh. 17. Epipactis palustris (L.) Crantz – Circumbore- ale. (CX, DX, GX, HX). Hum, Krti, Svi Sveti!, Vrh. 18. Gymnadenia conopsea (L.) R. Br. in W.T. Aiton susbp. conopsea – Eurasiatico. (CX, DX, FX, GX, HX, LX, MX, PX). Bartolići!, Bračana, Buzet!, Hum, Krti!, Marinci!, Pro- dani!, Ročko Polje!, Sv. Donat!, Svi Sveti!, Žonti. 19. Gymnadenia odoratissima (L.) Rich. – Euro- peo. (PX, SX). Roč, Sv. Donat. 20. Himantoglossum adriaticum H. Baumann – Eurimediterraneo. (CX, DX, FX,GX, HX, LX, NX, PX, RX). Bartolići!, Barušići, Butoniga Buzet!, Gornja Nugla!, Hum!, Krti!, Krušvari!, Mandalenići!, Marinci!, Podkuk, Roč, Sv. Do- nat!, Svi Sveti!, Veli Mlun! 21. Limodorum abortivum (L.) Sw. – Eurimedi- terraneo. (CX, DX, FX, GX, HX, PX, QX, SX). Barušići, Butoniga!, Buzet, Erkovčići, Gornja Nugla!, Hum, Krti!, Krušvari!, Ročko Polje!, Sv. Donat!, Vrh. 22. Listera ovata (L.) R. Br. – Eurasiatico. (BX, CX, DX, FX, GX, HX, PX, QY). Bartolići!, Ba- rušići, Buzet, Butoniga, Gornja Nugla, Hum, Krti, Sv. Donat. 23. Neotinea tridentata (Scop.) R.M. Bateman, Pridgeon & M.W. Chase – Eurimediterraneo. (CX, DX, GX, HX, SX). Buzet!, Krti, Krušvari!, Marinci!, Prodani!, Roč!, Sv. Donat!, Sv. Ivan!, Vrh! 24. Neotinea ustulata (L.) R.M. Bateman, Prid- geon & M. W. Chase – Europeo-Caucasico. (HX, SX). Krti! 25. Neottia nidus-avis (L.) Rich. – Eurasiatico. (CX, GX, HX). Buzet! 26. Ophrys apifera Huds. – Eurimediterraneo. (CX, DX, EX, FX, GX, HX, IX, LX, PX, SX). Bartolići, Barušići!, Butoniga!, Buzet!, Gor- nja Nugla!, Hum, Klarići, Krti!, Krušvari!, Mandalenići!, Penićiće!, Sv. Donat!, Veli Mlun!, Žonti! 27. Ophrys holosericea (Burm. f.) Greuter subsp. holosericea. – Eurimediterraneo. (FX, GX, PX). Barušići, Buzet, Krti, Marinci, Sv. Donat! 28. Ophrys holoser icea (Burm. f . ) Greuter subsp. tetra loniae (W.P. Teschner) Kreutz – Appennino-Balcanico. (AX, CX, DX, GX, HX, NX, PX, PY, SX). Bartol ići! , Buzet! , Krt i ! , Krušvari , Marinci! , Prodani! , Sv. Donat! , Svi Svet i ! , Vrh! Osservazioni. I l taxon ha i l suo locus classicus nel terr i to- r io di Buzet. 29. Ophrys holosericea (Burm. f.) Greuter subsp. untchjii (M. Schulze) Kreutz – Subendemico. (NX, SX). Barušići!, Krti!, Marinci!, Svi Sve- ti!, Žonti! 30. Ophrys incubacea Bianca subsp. incubacea – Stenomediterraneo.(DX). Buzet. ANNALES · Ser. hist. nat. · 31 · 2021 · 1 152 Amelio PEZZETTA: LE ORCHIDACEAE DI PINGUENTE (BUZET), 147–156 31. Ophrys insectifera L. – Europeo. (CX, GX, HX, NX, PX, SX). Buzet!, Erkovčići!, Hum!, Krti, Krušvari!, Marinci, Svi Sveti, Vrh! 32. Ophrys sphegodes subsp. sphegodes Mill. – Eurimediterraneo. (CX, DX, NX, PX). Bar- tolići!, Barušići, Buzet!, Erkovčići!, Hum!, Krti!, Krušvari!, Marinci!, Penićiće!, Proda- ni!, Sv. Donat!, Veli Mlun!, Svi Sveti!, Vrh! 33. Ophrys sphegodes subsp. tommasinii (Vis.) Soó – Appennino-Balcanico. (SX). Krti. 34. Orchis mascula L. subsp. speciosa (Mutel) – Centro-Europeo. (SX). Buzet!, Hum, Krti, Krušvari!, Marinci!, Ročko Polje!, Sv. Donat, Svi Sveti, Veli Mlun! 35. Orchis militaris L. – Eurasiatico. (CX, DX, GX, HX, SX). Barušići, Bračana!, Buzet. Hum, Krti!, Marinci!, Sv. Donat, Žonti! 36. Orchis purpurea Huds. – Eurasiatico. (CX, DX, FX, GX, HX, NX, PX, QY, SX). Bartolići!, Barušići, Butoniga, Buzet!, Erkovčići!, Gor- nja Nugla!, Krti!, Mandalenići!, Marinci!, Ročko Polje!, Sv. Donat!, Vrh!, Žonti! 37. Orchis simia Lam. – Eurimediterraneo. (DX, HX, PX, SX). Butoniga, Buzet, Hum!, Krti, Prodani!, Sv. Donat!, Svi Sveti. 38. Platanthera bifolia (L.) Rchb. subsp. bifolia – Paleotemperato. (CX, DX, FX, GX, HX, LX, PX, QY). Bartolići!, Butoniga, Buzet!, Hum, Krti!, Krušvari!, Mandalenići!, Marinci!, Pe- nićiće!, Prodani!, Sv. Donat!, Svi Sveti. 39. Platanthera chlorantha (Custer) Rchb. – Eu- rosiberiano. (DX, LX). Buzet, Krti, Sv. Donat, Vrh. 40. Serapias bergonii Camus – Mediterraneo-O- rientale. (GX). Krušvari. 41. Serapias vomeracea (Burm.f.) Briq. subsp. vomeracea – Eurimediterraneo. (CX, DX, FX, GX, HX, NX, PX, QY). Bartolići!, Butoniga, Buzet, Krti!, Krušvari!, Penićiće!, Prodani!, Sv. Donat!, Svi Sveti, Škuljari, Vrh, Žonti! Ibridi 1. Ophrys xhybrida Pokorny & R. (O. insectifera x O. sphegodes). Hum! 2. Orchis xbeyrichii (Reich. Fil.) A. Kern. (O. militaris x O. simia). ( PX). Butoniga. 3. Platanthera xhybrida Brügger (P. bifolia x P. chlorantha). (LX). Sv. Donat. L’elenco floristico comprende 41 taxa specifici e infraspecifici. Tale numero costituisce il 50 % delle Orchidaceae presenti nella penisola istriana e circa il 23 % della Repubblica di Croazia. A tale insieme si aggiungono 3 ibridi per cui l’am- montare complessivo delle entità presenti è 44, un valore numerico che, tenendo conto di quanto riportato in Pezzetta (2018a), colloca il territorio di Buzet tra i Comuni istriani più ricchi di orchi- dacee. L’elenco comprende molte segnalazioni di località e stazioni inedite che contribuiscono ad allargare l’areale di diffusione dei singoli taxa nel territorio istriano. Il geoportale della flora croatica (Nikolić, 2015) riporta la presenza di 24 taxa nel territorio della città di Buzet. Quindi con tale saggio, l’am- bito di studio si arricchisce di 17 taxa specifici e infraspecifici e 3 ibridi. Dalla Tabella 1 emerge che le varie entità si ri- partiscono in 15 generi tra cui il più rappresentato è il genere Ophrys con 8 taxa. Seguono i generi: Anacamptis con 6; Epipactis con 5; Orchis con 4, Dactylorhiza con 3; Cephalanthera, Gymnadenia, Neotinea, Platanthera e Serapias con 2; tutti gli altri con un taxon ciascuno. La Tabella 2 mostra che l’insieme dei taxa è presente in 26 località. Il maggior numero di se- gnalazioni si registra nei dintorni di Buzet con 30 taxa, Krti con 29 e Sv. Donat con 26. Un discreto numero di taxa si rinviene presso Hum (21), Ba- rušići (15), Marinci (15), Svi Sveti (15), Krušvari (14) e Bartolići (13). Riassumendo si può dire che in tutto il territorio comunale le Orchidaceae sono relativamente diffuse poiché il loro sviluppo è favorito dalla bassa pressione antropica e dalle varietà delle nicchie ecologiche. Le entità segnalate nel maggior numero di località e quindi più diffuse sono le seguenti: Genere Numero taxa Genere Numero taxa Anacamptis 6 Listera 1 Cephalanthera 2 Neotinea 2 Coeloglossum 1 Neottia 1 Dactylorhiza 3 Ophrys 8 Epipactis 5 Orchis 4 Gymnadenia 2 Platanthera 2 Himantoglossum 1 Serapias 2 Limodorum 1 Tab. 1: Biodiversità dei Generi delle Orchidaceae di Pinguente. Tab. 1: Biodiverziteta in rodovi kukavičevk v Buzetu. ANNALES · Ser. hist. nat. · 31 · 2021 · 1 153 Amelio PEZZETTA: LE ORCHIDACEAE DI PINGUENTE (BUZET), 147–156 Anacamptis pyramidalis (17), Himantoglossum adriaticum (15), Ophrys apifera (14), O. sphe- godes subsp. sphegodes (14), Anacamptis morio (13), Orchis purpurea (13), Platanthera bifolia (12), Serapias vomeracea (12). Gymnadenia co- nopsea (11) e Limodorum abortivum (11). In Tabella 3 sono riportati i risultati dell’anali- si corologica, con la ripartizione percentuale dei vari contingenti geografici. Si può osservare come il contingente Mediterraneo sia dominante con 16 taxa. Esso è seguito dai contingenti: Eurasiatico con 14 taxa, Europeo con 8, Nordico con 2 ed Endemico con un solo taxa. Nel complesso nell’area sono più rappresenta- ti i corotipi mesotermici (Appennino-Balcanico, Eurasiatico, Europeo, Centro-Europeo, Europe- o-Caucasico, e Paleotemperato). La presenza contemporanea di taxa appartenenti ai corotipi mesotermici, microtemici (Eurosiberiano e Cir- cumboreale) e macrotermici (contingente Medi- terraneo) confermano che l’ambito di studio è caratterizzato da una grande varietà ambientale e climatica che consente l’attecchimento di entità vegetali con esigenze ecologiche molto diversi- ficate. Conclusioni I dati riportati dimostrano l’importanza dell’ambito di studio per la ricchezza di orchida- cee. Il considerevole numero rilevato è un indi- catore della sua buona qualità ambientale poiché Località Taxa totali Località Taxa totali Bartolići 13 Marinci 15 Barušići 15 Penićiće 5 Bračana 7 Podkuk 1 Butoniga 10 Prodani 11 Buzet 30 Roč 4 Črnica 1 Ročko polje 6 Erkovčići 6 Sv. Donat 26 Gornja Nugla 7 Svi Sveti 15 Hum 21 Škuljari 1 Klarići 1 Štrped 1 Krti 29 Veli Mlun 7 Krušvari 14 Vrh 14 Mandalenići 4 Žonti 7 Tab. 2: Località di Pinguente con presenza di orchidacee. Tab. 2: Lokalitete Buzeta in okolice ter število taksonov kukavičevk. Contingenti Geografici1 e Corotipi Numero taxa % Endemico 1 2,44 Subendemico 1 Mediterraneo 16 39,02 Eurimediterraneo 14 Stenomediterraneo 1 Mediterraneo-Orientale 1 Eurasiatico 14 34,15 Eurasiatico s.s. 7 Europeo-Caucasico 3 Eurosiberiano 2 Paleotemperato 2 Nordico 2 4,88 Circumboreale 2 Europeo 8 19,51 Europeo s.s. 4 Centro-Europeo 2 Appennino-Balcanico 2 Totale 41 100 Tab. 3: Corotipi delle Orchidaceae del Comune di Buzet. Nella tabella i contingenti geografici sono segnati in grassetto (1). Tab. 3: Horotipi kukavičevk v občini Buzet. V tabeli so geografski kontingenti označeni z mastnim tiskom (1). ANNALES · Ser. hist. nat. · 31 · 2021 · 1 154 Amelio PEZZETTA: LE ORCHIDACEAE DI PINGUENTE (BUZET), 147–156 le piante di tale famiglia vegetale attecchiscono su terreni che non sono alterati da dissoda- menti, concimazioni e largo uso di diserbanti e insetticidi. L’ambito di studio nella situazione attuale è poco popolato e non sembra che le varie entità siano minacciate. È tuttavia possibile che a causa della diffusione delle aree urbane, artigianali, industriali, delle infrastrutture di trasporto, dell’espansione delle aree forestali e dell’abbandono delle pratiche agro-pastorali tra- dizionali seguano trasformazioni di habitat che potrebbero portare a una diversa ripartizione delle varie specie con alcune in fase espansione e altre in contrazione. ANNALES · Ser. hist. nat. · 31 · 2021 · 1 155 Amelio PEZZETTA: LE ORCHIDACEAE DI PINGUENTE (BUZET), 147–156 KUKAVIČEVKE BUZETA Amelio PEZZETTA Via Monte Peralba 34 - 34149 Trieste e-mail: fonterossi@libero.it POVZETEK Buzet (Hrvaška) se nahaja v severozahodni Istri in pokriva približno 167 km2 površine. V pričujočem delu, ki temelji na neposrednih popisih, literaturnih virih in neobjavljenih podatkih, avtor podaja ažurirani seznam vseh kukavičevk, potrjenih na obravnavanem območju. 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ANNALES · Ser. hist. nat. · 30 · 2020 · 1 157 Claudio BATTELLI & Neža GREGORIČ: FIRST REPORT OF AN AEGAGROPILOUS FORM OF RYTIPHLAEA TINCTORIA FROM THE LAGOON OF STRUNJAN ..., 61–68 FAVNA FAVNA FAVNA ANNALES · Ser. hist. nat. · 30 · 2020 · 1 158 Claudio BATTELLI & Neža GREGORIČ: FIRST REPORT OF AN AEGAGROPILOUS FORM OF RYTIPHLAEA TINCTORIA FROM THE LAGOON OF STRUNJAN ..., 61–68 ANNALES · Ser. hist. nat. · 31 · 2021 · 1 159 received: 2020-10-05 DOI 10.19233/ASHN.2021.19 CALIGUS MINIMUS (COPEPODA: CALIGIDAE) PARASITIC ON THE GILLS OF A REMORA ECHENEIS NAUCRATES ATTACHED TO A SEABASS DICENTRARCHUS LABRAX IN KÖYCEĞİZ-DALYAN LAGOON LAKE, AEGEAN SEA, TURKEY Ahmet ÖKTENER Department of Fisheries, Sheep Research Institute, Çanakkale Road 7.km, 10200, Bandırma, Balıkesir, Turkey e-mail: ahmetoktener@yahoo.com Ivan SAZIMA Museu de Zoologia, Universidade Estadual de Campinas, 13083-863 São Paulo, Brazil ABSTRACT The paper describes a parasitic copepod Caligus minimus found on the gill rakers of a remora Echeneis naucrates attached to a seabass Dicentrarchus labrax in the brackish Köyceğiz-Dalyan Lagoon Lake on the shore of the South Aegean Sea, Turkey. Morphological characters of the female copepod are provided and illustrated. The occurrence of this parasitic copepod species on a remora host and the association between this remora species and seabass in a brackish lagoon constitute new records. The present study elevates to four the Caligus species found on E. naucrates so far. We suggest two mutually non-exclusive scenarios for the occurrence of E. naucrates on D. labrax in brackish environments. Key words: Caligidae, fish parasite, remora-seabass association, Turkey CALIGUS MINIMUS (COPEPODA: CALIGIDAE) PARASSITA SULLE BRANCHIE DI UNA REMORA ECHENEIS NAUCRATES ATTACCATA A UNA SPIGOLA DICENTRARCHUS LABRAX NEL LAGO LAGUNARE KÖYCEĞİZ-DALYAN, MAR EGEO, TURCHIA SINTESI L’articolo descrive un copepode parassita Caligus minimus trovato sui rastrelli branchiali di una remora Echeneis naucrates attaccata ad una spigola Dicentrarchus labrax nel lago salmastro Köyceğiz-Dalyan Lagoon sulla riva dell’Egeo meridionale, in Turchia. I caratteri morfologici del copepode femmina sono forniti e illustrati. L’occorrenza di questa specie di copepode parassita su un ospite remora e l’associazione tra questa remora e la spigola in una laguna salmastra rappresentano dati nuovi. Il presente studio eleva a quattro le specie di Caligus trovate finora su E. naucrates. Gli autori suggeriscono due scenari reciprocamente non esclusivi per la presenza di E. naucrates su D. labrax in ambienti salmastri. Parole chiave: Caligidae, parassita dei pesci, associazione remora-spigola, Turchia ANNALES · Ser. hist. nat. · 31 · 2021 · 1 160 Ahmet ÖKTENER & Ivan SAZIMA: CALIGUS MINIMUS (COPEPODA: CALIGIDAE) PARASITIC ON THE GILLS OF A REMORA ECHENEIS NAUCRATES ... , 159–164 INTRODUCTION Research on gill parasites in remoras (Echeneidae) is scarce. A remarkable example of it is the study of the com- plex relationship between a monogenean (Dionchus sp.), a shark (Carcharhinus limbatus (Müller & Henle, 1839)), and a remora (Echeneis naucrates Linnaeus, 1758) (Figure 3 in Bullard et al., 2000). So far there have been very few records of caligid copepods on E. naucrates (e.g., Wilson, 1905; Causey, 1953; Cressey, 1991), none of them Caligus minimus Otto, 1821. We report herein on a C. minimus attached to the gills of the slender sharksucker Echeneis naucrates and the association between this remora species and the European seabass Dicentrarchus labrax (Linnaeus, 1758) in a brackish lagoon of the South Aegean Sea, Turkey. Caligus minimus is a widespread oioxenous species, i.e., it has a wide range of hosts (Öktener & Trilles, 2009; Boualleg et al., 2011; Tanrıkul & Perçin, 2012; Hafir- Mansouri et al., 2017). It is found on gills, mouth, or body surface of the hosts, and is able to live in brackish waters (Fonsêca et al., 2000; Tanrıkul & Perçin, 2012; Yalım et al., 2014). Echeneis naucrates is cosmopolitan and may live free-swimming or attached to a variety of fish hosts, including sharks, rays, bony fishes, sea turtles, dolphins, and whales (Strasburg, 1964; O’Toole, 2002; Brunnsch- weiller & Sazima, 2008, 2010; Santos & Sazima, 2008), and is able to live in brackish waters (Akyol & Balık, 2007; Santos & Sazima, 2008; Marletta & Lombardo 2020). Dicentrarchus labrax inhabits the Eastern Atlantic and the Mediterranean (Freyhof & Kotellat, 2008), is eurythermic (5-28 °C) and euryhaline (3‰ to full strength seawater), which allows it to dwell in coastal inshore waters, estuar- ies, and in brackish water (Bagni, 2005). MATERIAL AND METHODS A specimen of Echeneis naucrates attached to a Dicentrar- chus labrax was caught in a fish trap in the Köyceğiz-Dalyan Lagoon (36.824967 N, 28.632510 E, 0 m a.s.l., 5 m depth) on the shores of the South Aegean Sea during parasitological surveys conducted by the first author in 2019. Parasites were removed from the gill rakers of the sharksucker, fixed in 4% formaldehyde and preserved in 70% ethanol. The copepod specimens were cleared in pure lactic acid for a minimum of 24 h and later dissected under a Wild M5, Leica M140 stereo-microscope. Photos were taken with the aid of a Canon camera (EOS 1100D) connected to the microscope. Measurements were recorded in millimetres. The append- ages were measured using a micrometric programme (Pro- way). Identification and terminology follows Kabata (1979) and Öktener et al. (2017). RESULTS Subclass Copepoda Milne Edwards, 1840 Order Siphonostomatoida Thorell, 1859 Family Caligidae O.F. Müller, 1785 Caligus minimus Otto, 1821 (Figs. 1-3, Tab. 1) Female morphology (Fig.1): Body length 3.014 mm; width 1.335mm. Cephalothorax longer than wide. Fourth pediger a little longer than wide. Genital complex longer than wide. First abdominal segment longer than wide. Caudal ramus longer than wide. Exopod of first leg with two middle setae carrying narrow flanges at apices. Anten- nule (Fig. 2a) two-segmented; distal segment longer than proximal, distal segment bearing 12 setae and 1 subtermi- nal seta on ventral margin, the proximal segment armed with 23 plumose setae. Antenna (Fig. 2b) 3-segmented; first segment features small; second segment nearly quad- rangular; third segment long, distally strongly bent curved claw; subchela with a small seta. Postantennal process (Fig. 2b) smaller than antenna. Postantennal process slightly curved, carrying 3 papillae, each with 3 sensillae. Mandible (Fig. 2c) tip with 12 teeth. Maxillule (Fig. 2d) bearing a papilla with 3 unequal setae. Maxilla (Fig. 2e) two-segmented; proximal segment large and unarmed; slender distal segment with hyaline membrane on outer margin and tipped distally with 2 unequal processes. Max- illiped (Figs. 2f, g) proximal segment (corpus) the largest; distal two segments fused to form a claw carrying a small seta at base of claw. Tines of sternal furca (Fig. 2h) slightly curved inward. Caudal rami (Fig. 2i) with 3 long and 3 short setae. Shapes from first leg to fourth leg presented in Figs. 3a-3d, the formula from first leg to fourth leg in Tab. 1. Fig. 1: Caligus minimus ♀ habitus (scale 1 mm) found fastened to gill filaments of Echeneis naucrates attached to Dicentrarchus labrax host (Photo: A. Öktener). Sl. 1: Caligus minimus ♀ (merilo 1 mm) na škržnih filamentih prilepa Echeneis naucrates, pritrjenega na brancina (Dicentrarchus labrax) (Foto: A. Öktener). ANNALES · Ser. hist. nat. · 31 · 2021 · 1 161 Ahmet ÖKTENER & Ivan SAZIMA: CALIGUS MINIMUS (COPEPODA: CALIGIDAE) PARASITIC ON THE GILLS OF A REMORA ECHENEIS NAUCRATES ... , 159–164 The sharksucker Echeneis naucrates was about 30 cm total length (TL) with a slim brownish grey body, dark pectoral, pelvic, and caudal fins, and a barely visible darker stripe running from head to tail. The cephalic disk was about 6 cm long (20% of TL). The slim body, the colour, and the relative size of the cephalic disk are diagnostic of this remora species. Its stomach contents revealed no parasites. Its host, a sea bream Dicentrarchus labrax, measured about 60 cm TL and was sluggish, with wounds and intense mucus covering its body surface. We were unable to collect the sharksucker and the seabass, and we did not examine the seabass for parasites. DISCUSSION Our record of C. minimus raises to four the species of siphonostomatoid copepods found parasitising Echeneis naucrates. Previously, Caligus praetextus Bere, 1936 (Caligidae), Tuxophorus caligodes Wilson, 1908 (Tuxo- phoridae), and Margolisius cf. abditus (Lernaeopodidae) were reported from this remora species (Wilson, 1908; Cressey, 1991; Justine, 2010). Margolisius abditus Benz, Kabata & Bullard, 2000 was reported to have been found on the gill lamellae of another remora species, Remora remora (Linnaeus) (Benz et al., 2000). Fifteen species of parasitic copepods, including C. minimus, have been recorded for Dicentrarchus labrax (WoRMS, 2020). Incidentally, D. labrax is a new host for E. naucrates (O’Toole, 2002; Brunnschweiller & Sazima, 2008, 2010). This remora species is uncommon in the Mediterranean and may occur in brackish lagoons (Akyol Tab. 1: Caligus minimus ♀ setal and spinal formula from first to fourth leg. Tab. 1: Caligus minimus ♀: formula ščetin in trnov od prve do četrte okončine. Legs Endopod Exopod First leg (Fig. 3a) vestigial I-0; IV-3 Second leg (Fig. 3b) 1-0; 2-0; 6-0 I-1; I-1; III-5 Third leg (Fig. 3c) 1-0; 6-0 I-0; I-1; III-4 Fourth leg (Fig. 3c) absent I-0; I, II Fig. 2: Caligus minimus ♀ a) antennule, b) antenna and postantennal process, c) mandible, d) maxillule, e) maxilla, f) maxilliped, g) distal of maxilliped, h) sternal furca, i) caudal ramus (Photo: A. Öktener). Sl. 2: Caligus minimus ♀ a) antenula, b) antena in postantenski izrastek, c) mandibula, d) maksilula, e) maksila, f) maksiliped, g) distalni del maksilipeda, h) sternalna vilica, i) repni izrastek (Foto: A. Öktener). ANNALES · Ser. hist. nat. · 31 · 2021 · 1 162 Ahmet ÖKTENER & Ivan SAZIMA: CALIGUS MINIMUS (COPEPODA: CALIGIDAE) PARASITIC ON THE GILLS OF A REMORA ECHENEIS NAUCRATES ... , 159–164 & Balık, 2007; Marletta & Lombardo 2020). Thus, the occurrence of C. minimus, E. naucrates, and D. labrax in the brackish Köyceğiz-Dalyan Lagoon Lake matches the knowledge about salinity tolerance of all three organisms (Bagni, 2005; Akyol & Balık, 2007; Fonsêca et al., 2010; Kyne, 2015; Marletta & Lombardo 2020). The wounds ob- served on the body of D. labrax could be due to infestation by C. minimus (Noor El-Deen et al., 2013) or some other parasite, but we were unable to confirm this hypothesis. We suggest that the presence of C. minimus on E. naucrates attached to D. labrax can be explained by two scenarios, which are not mutually exclusive: 1) the caligid fastened to the sharksucker when it fed on the parasites and the diseased or dead tissue of the seabass host; 2) the sharksucker swam freely in the lagoon without a host and picked up the caligid when it attached to the seabass. Our scenarios are supported by the biology of E. naucrates, as this remora lives free-swimming or attached to a host, from which it picks parasites and dead tissue, changing hosts from time to time (Strasburg, 1964; Cressey & Lachner, 1970; Brunschweiler & Sazima, 2008, 2010). Additionally, remoras may pick up parasites from a host and then transfer them to another host, as postulated by Bullard et al. (2000), which strengthens our suggestions above. CONCLUSIONS Our finding of the caligid copepod C. minimus on the gills of the slender sharksucker E. naucrates raises to four the Caligus species recorded on this remora species to date. The association of E. naucrates with the seabass D. labrax in a brackish lagoon is a new record for the Mediterranean Sea. ACKNOWLEDGEMENTS We thank to S.S DALKO Köyceğiz-Dalyan Aquatic Products Cooperative President Mr.Arif Yalılı, who helped in obtaining the host fish and the remora. Two anonymous reviewers improved the manuscript. Fig. 3: Caligus minimus ♀ a) first leg, b) second leg, c) third leg, d) fourth leg (Photo A. Öktener). Sl. 3: Caligus minimus ♀: a) prva okončina, b) druga okončina, c) tretja okončina, d) četrta okončina (Foto: A. Öktener). ANNALES · Ser. hist. nat. · 31 · 2021 · 1 163 Ahmet ÖKTENER & Ivan SAZIMA: CALIGUS MINIMUS (COPEPODA: CALIGIDAE) PARASITIC ON THE GILLS OF A REMORA ECHENEIS NAUCRATES ... , 159–164 CALIGUS MINIMUS (COPEPODA: CALIGIDAE), ZAJEDAVEC NA ŠKRGAH PRILEPA (ECHENEIS NAUCRATES), PRITRJENEGA NA BRANCINA (DICENTRARCHUS LABRAX ) V LAGUNI KÖYCEĞİZ-DALYAN V EGEJSKEM MORJU, TURČIJA Ahmet ÖKTENER Department of Fisheries, Sheep Research Institute, Çanakkale Road 7.km, 10200, Bandırma, Balıkesir, Turkey e-mail: ahmetoktener@yahoo.com Ivan SAZIMA Museu de Zoologia, Universidade Estadual de Campinas, 13083-863 São Paulo, Brazil POVZETEK Avtorja poročata o najdbi zajedavskega raka ceponožca vrste Caligus minimus, najdenega na škržnih ščetinah prilepa Echeneis naucrates, ki je bil pritrjen na brancina Dicentrarchus labrax iz brakične lagune Köyceğiz-Dalyan v južnem Egejskem morju (Turčija). Podajata morfološke znake samice raka ceponožca in slikovno gradivo. Pojavljanje zajedavskega ceponožca na prilepu in zajedanje slednjega na brancinu predstavlja nove podatke o teh odnosih. S pričujočimi podatki se je število zajedavskih vrst iz rodu Caligus, ki zajedajo prilepe, povečalo na 4. Nadalje avtorja razpravljata o pojavljanju prilepa na brancinu v brakičnem okolju na podlagi dveh scenarijih, ki se ne izključujeta. Ključne besede: Caligidae, ribji zajedavec, združba prilep-brancin, Turčija ANNALES · Ser. hist. nat. · 31 · 2021 · 1 164 Ahmet ÖKTENER & Ivan SAZIMA: CALIGUS MINIMUS (COPEPODA: CALIGIDAE) PARASITIC ON THE GILLS OF A REMORA ECHENEIS NAUCRATES ... , 159–164 REFERENCES Akyol, O. & İ. Balık (2007): Occurrence of the live sharksucker Echeneis naucrates Echeneidae in the Beymelek Lagoon Turkey eastern Mediterranean. Cybium, 31, 487-488. Bagni, M. (2005): Dicentrarchus labrax. Cultured Aquatic Species Information Programme. In: FAO Fisheries Division [online]. Rome. Updated 18 February 2005. 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Proceedings of the United States National Museum, 28, 593-627+16 pl https://doi. org/10.5479/si.00963801.28-1404.479 Wilson, C.B. (1908): North American parasitic copepods: new genera and species of Caliginae. Proceedings of the United States National Museum 33, (1580), 593-627. WoRMS Editorial Board (2020): World Register of Marine Species. Available from http://www.marinespecies.org at VLIZ. Accessed 2020-09-22. doi:10.14284/170. Yalım, F.B., N. Emre & Y. Emre (2014): Caligus minimus (Copepoda, Caligidae) infestation of European sea bass (Dicentrarchus labrax) from Beymelek Lagoon Lake (Antalya, Turkey): effects of host sex, age, size and season. Journal of Academic Documents for Fisheries and Aquaculture, 1, 9-16. 165 ANNALES · Ser. hist. sociol. · 30 · 2020 · 1 KAZALO K SLIKAM NA OVITKU SLIKA NA NASLOVNICI: Sinji morski pes (Prionace glauca) je široko razširjena oceanska vrsta, ki se pojavlja v tropskih in subtropskih morjih. Včasih je bil eden izmed najpogostejših morskih psov, danes pa je zaradi prelova marsikje ogrožen. (Foto: B. Furlan) Sl. 1: Sinjega morskega psa (Prionace glauca) hitro prepoznamo po dolgem gobcu in dolgih prsnih plavutih, od drugih morskih psov pa ga lahko ločimo tudi po značilni modri barvi. (Foto: B. Furlan) Sl. 2: Poleg mnogih drugih morskih vretenčarjev zapuščene in odtrgane mreže ogrožajo tudi morske pse in skate. Ta nesrečni primerek velike morske mačke (Scyliorhinus stellaris) se je zapletel v ostanke morske mreže v vodah blizu otoka Biševo na južnem Jadranu. (Foto: B. Furlan) Sl. 3: Tujerodna modra rakovica (Callinectes sapidus) že dlje časa naseljuje Sredozemsko morje. Je na seznamu stoterice najnevarnejših invazivnih vrst v Sredozemskem morju in domnevajo, da negativno vpliva na samoni- klo biodiverziteto in ribištvu. (Foto: S. Ciriaco) Sl. 4: Sinji morski pes (Prionace glauca) se pojavlja tudi v Jadranskem morju, predvsem v njegovem severnem delu. Po mnenju strokovnjakov se v tem plitvem okolju tudi razmnožuje. (Foto: B. Furlan) Sl. 5: Vedno znova se v Sredozemskem morju pojavljajo vrste, ki vanj prihajajo iz Indijskega oceana prek Su- eškega prekopa. Med njimi je tudi rdečepikasta kirnja (Epinephelus areolatus), ki so jo pred kratkim opazili ob obalah Sirije. (Foto: B. Furlan) Sl. 6: Majhnocvetno čmrljeliko mačje uho (Ophrys holosericea subsp. tetraloniae) je submediteranska kukavi- čevka, ki uspeva tudi v slovenski in hrvaški Istri. Kot vse kukavičevke ima tudi ta v Sloveniji status zavarovane rastlinske vrste. (Foto: L. Lipej) INDEX TO IMAGES ON THE COVER FRONT COVER: The blue shark (Prionace glauca) is a widespread oceanic species occurring in tropical and subtro- pical seas. While it used to be one of the most common sharks, it is nowadays endangered in many places due to overfishing. (Photo: B. Furlan) Fig. 1: The blue shark (Prionace glauca) is readily recognised by its long muzzle and long pectoral fins. It can also be distinguished from other sharks by its characteristic blue colour. (Photo: B. Furlan) Fig. 2: Like many other marine vertebrates, sharks and skates are threatened by abandoned fishing nets. This unfor- tunate specimen of nursehound (Scyliorhinus stellaris) became entangled in a ghost net in the waters near the Island of Biševo in the southern Adriatic. (Photo: B. Furlan) Fig. 3: The alien blue crab (Callinectes sapidus) has been colonising the Mediterranean Sea for a long time. It is listed as one of the hundred most dangerous invasive species in the Mediterranean and is thought to have an impact on wildlife biodiversity and fisheries. (Photo: S. Ciriaco). Fig. 4: The blue shark (Prionace glauca) also occurs in the Adriatic Sea, especially in its northern part. According to experts, it also reproduces in this shallow environment. (Photo: B. Furlan) Fig. 5: Alien fish species have been constantly entering the Mediterranean Sea from the Indian Ocean via the Suez Canal. Among them is the red-spotted grouper (Epinephelus areolatus), which was recently spotted off the coast of Syria. (Photo: B. Furlan) Fig. 6: Bee orchid (Ophrys holosericea subsp. tetraloniae) is a sub-Mediterranean orchid that thrives in Slovenian and Croatian Istria. Like all wild orchids, this species has the status of protected plant species in Slovenia. (Photo: L. Lipej) 166 ANNALES · Ser. hist. sociol. · 30 · 2020 · 1 167 ANNALES · Ser. hist. sociol. · 30 · 2020 · 1