ANNALES • Ser. hist. nat. • 10 • 2000 • 1 (19) original scientific paper UD C 597(262.3-11 ) OCCURRENCE OF BLUEFISH, POM A TOM US SAL TA TOR (LINNAEUS, 1766), AND BUTTERFISH, STROMATEUS FIATOLA (LINNAEUS, 1 758), JUVENILES IN THE EASTERN CENTRAL ADRIATIC Inkov DULČiČ, Armin PALLAORO & Miro KRALJEVIČ Institute of Oceanography and Fisheries, HR-21000 Split, P.O.BOX 500 ABSTRACT The bluefish, Pomatomus sal fa tor, and butterfish, Stromateus fiatola, juveniles were caught near Cape Ciovo (island of Ciovo, eastern central Adriatic) and near StonCica station (island of Vis, eastern central Adriatic) in Sep­tember 1999, respectively. There are no previous records of the bluefish and butterfish juveniles in the easfem Adriatic, although several studies and investigations on fish juvenile stages were carried out between 1975 and 1998 in the eastern Adriatic. The main morphometric and meristic data are given. Key words: Pomatomus saltator, Stromateus fiatola, juveniles, eastern Adriatic, first occurrence RITROVAMENT O DI STADÎ GiOVANILI DI PESCE SERRA, POMATOMUS SALTATOR, (UNNAEUS , 1766) E Dl FiETO, STROMATEUS FIATOLA (UNNAEUS , 1758), NELL'ADRIATiCO CENTRO-ORIENTALE SINTESI Stadi giovanili di pesce serra, Pomatomus saltator, e di fieto, Stromateus fiatola, sono stati catturati nelle vicinan­ze di capo Čiovo (isola di Čiovo, Adriático centro-orientale) e del la stazione di Stončica (isola di Vis, Adriático cen­tro-orientale) a setiembre de! 1999. Sebbene ira !I 1975 ed i! 1998 siano stati condotti numerosi studi sugli stadi giovanili di pesci nell'Adríatico orientale, non risulta alcuna segnalazione precedente de! ritrovamento di stadi giovanili di pesce serra e di fleto ne!!Adriático orientale. Nell'articolo vengono ríportati i dati morfometríci e meri­stici. Parole chiave: Pomatomus saltator, Stromateus fiatola, stadi giovanili, Adriático orientale, primo ritrovamento INTRODUCTIO N occurs near the bottom over continental shelves from 12 to 50 m in depth. It occurs at the Atlantic coasts from The bluefish, Pomatomus saltator (Linnaeus, 1766), the Bay of Biscay (rare) southward to Cape Town, and in is a pelagic species living in shoals (chiefly when young) the Mediterranean (not Adriatic) (Haedrich, 1986). jar-along the continental shelf from 0 to 200 m. It is com-das (1996) reported about its presence in the Adriatic mon In the eastern Atlantic from Portugal, Madeira, the Sea (fairly rare). Canaries, southward along African coasts to South Af-There is no published information on biology and rica, also in the Mediterranean and the Black Sea ecology of both species in the Adriatic. The aim of this (elsewhere, subcosmopoiitan in tropical and subtropical paper is to provide first data on the occurrence of ju­seas) (Tortonese, 1986). This species is fairly rare in the veniles of the bluefish and butterfish in the eastern Adriatic Sea (Jardas, 1996). Adriatic and their morphometric and meristic character- The butterfish, Stromateus fiatola Linnaeus, 1758, istics. 19 ANNALES • Ser. hist. nat. • 10 • 2000 • 1 (19) lakov DUIČ1Č etui.: OCCURRENC E O F BLUEFISH, POMATOMUS SALTATOR (LiNNAEUS, 1766),..., 19-22 Fig. 1: Sites where juveniles of Pomatomus saltator and Strom ate us fiatola were found (A - Cape Ciovo, island of Ciovo; 8 - Cape Stoncica, island of Vis). Si. 1: Lokacije, na katerih so bile ujete mladice Poma­tomus saltator in Stromateus fiatola (A - rt Ciovo, otok Ciovo; B - rt Stoncica, otok Vis). MATERIAL AN D METHODS The bluefish juvenile was caught (29.09.1998) near Cape Ciovo (island of Ciovo, eastern central Adriatic) at the depth between 15 and 20 m on sandy-muddy bot­tom covered by Posidonia oceanica (Fig. 1). The butter-fish juvenile was caught by bottom trammel set (23.09.1998) near Stondca station (island of Vis, eastern central Adriatic) at the depth of 20 m on rocky-sandy­muddy bottom (Fig. 1). The specimens were identified according to Soijan (1975). They are deposited in the Ichthyologtcai Collec­tion of the Institute of Oceanography and Fisheries in Split, Croatia. The specimens were preserved in 4 % buffered for­maldehyde immediately after capture, subsequently measured to the nearest 0.01 mm, and weighed to the nearest 0.01 g. Reduction in length caused by preserva­tion depends on initial lengths of the specimens and du­ration of storage. Meristic characteristics considered were dorsal, anal, pectoral, ventral, caudal fins, and number of scales in the longitudinal line and denies. RESULTS AN D DISCUSSION juveniles of the bluefish have elongate compressed body and large head (Fig. 2). Mouth terminal, lower jaw is slightly prominent. Pectoral fin is short, not reaching to origin of soft dorsal fin. Colour is silvery, greenish-grey on back and there is a longer black spot at the base of pectoral fin. juveniles of the butterfish have deep compressed body. Eyes and mouth small, dorsal fin single and long based, longer than the similar anal fin. Anterior rays longer than those, which follow, but fins not falcate. Pectoral fins broad and wing-like, but not prolonged, while pelvic fins are absent Colour is generally bluish on the back, with dark vertical bars, and whitish on the sides and below, overall with a silver cart. Studies on larva! and juvenile stages of fish are of particular importance to population dynamics, espe­cially to recruitment and biological models incorporat­ing environmental parameters (Houde, 1986; Myers & Cadigan, 1993). The bluefish and butterfish are fairly rare species in the Adriatic Sea (Jardas, 1996; Paliaoro & jardas, 1996). Graeffe (1888) reported about the pres­ence of both species at Trieste fish market and their oc­currence together with jellyfish Rhizostoma puimo L From that time oniy several specimens of the bluefish have been caught until now in the eastern Adriatic, the first one near Oubrovnik in June 1887, and the second near Split (without data on date of capture) registered by j. Kolombatovic (Langhoffer, 1903). Further records were made near Vranjic (Split area) on June 1 6 in 1938, and in Tarska Cove - Novtgrad (istra peninsula) on De­cember 6 in 1991. The first record of the butterfish was made near Ri­jeka on July 16th in 1896 (Langhoffer, 1903). Other re­cords were in the Neretva Channel on November 20 in 1944 (Onofrt, 1997), in Trpanj area (Peljesac peninsula) on February 2 in 1996 (Paliaoro & Jardas, 1996), in Dubrovnik area (without data on date of capture) (Musin, 1989) and in Vis Channel (without data on date of capture) (Onofri, 1983). Fig. 2: Juvenile specimen of the bluefish Pomatomus saltator. SI. 2: Mladica skakavke Pomatomus saltator. 20 ANNALE S Ser. hist. nat. • 10 2000 • 1 (19) lakov DUIČI Č e/a/.: OCCURRENCE. O F BLUE FISH, POMATOMUS SAI. TATOR (LINNAEUS, 1766) 19-22 in table 1 the main morphometric and meristic data of both species are presented. Tab. 1. Morphometric (in mm) and meristic data of the bluefish and butterfish juveniles in the eastern Adriatic. Tab. I. Morfometrični (v mm) in meristični podatki o mladicah skakavke in fige v vzhodnem Jadranu, Species Pomatomus Stromateus sal ta tor ft atol a Weight (W) (g) 250.3 44.30 Morphometric characters (cm) Total length (TL) 30.20 16.30 Standard length (St) 25.60 12*62 Head length (C) 6.56 2.99 Predorsal length (LPD) 8.83 3.62 Preanal length (LPA) 15.14 5.31 Prepectoral length (LPP) 7.23 3.24 Pre ventral length (LPV) 7.86 3.42 First dorsal fin length (LD1) 3.60 7.42 Second dorsal fin length (LD2) 6.98 ­ Anal fin length (A) 6.40 5,01 Pectoral fin length (LP) 4.33 2.88 Ventral fin length (LV) 2.95 0.22 Caudal fin length (LC) 6.15 3.76 Maximal body height (Tmax) 6.59 6.45 Minimal body height (Tmin) 2.08 0.97 Eye diameter (O) 1.08 0.59 Interorbitai length (!o) 1.71 1.29 Preorbital length (Po) 1.66 0.85 Postorbital length (Olo) 3.97 1.65 Meristic characters First dorsal fin (D1) Vil VI/4 4 „ Second dorsal fin (D2) 25 Anal fin (A) 111/24 ill/34 Pectoral fins (P) 16 23 Ventral fins (V) 1 / 5 + 5 / I 3 Caudal fin (C) 111 + 16 + 111 IV + 16 + IV Linea lateralis (Ll) 102 - Dentes sup. 15 ­ Denies inf. 18 ­ There are no previous records of the bluefish and butterfish juveniles in the eastern Adriatic, although sev­eral studies and investigations on fish juvenile stages were carried out between 1975 and 1998 in the eastern Adriatic. The meristic characteristics of the bluefish juveniles (Tab. 1) slightly differ from data by Tortonese (1986), i.e. D1 Vll-Vlll, D2 1+2-28, A !1+23-27, while the character­istics of butterfish differ from data by Haedrich (1986), i.e. D 42-50, A 33-38, P 21-25. Theses September records show that both species probably spawn in the middle Adriatic or even more to the south, especially whe n w e take into consideration that the bluefish spawns in spring and summer (Tortonese, 1986). There are no data about reproduction of the butterfish in the Mediterranean, but this record could suggest that it is probably in the summer period, whic h is in agreement with the findings for Adriatic (Jardas, 1996). W e suppose that both specimens are about one year old according to the spawning season. Spawning of the bluefish was limited to the warmest months, from July to September along the Catalan coast, when the surface temperature was about 25°C, suggest­ing an inshore spawning (Sabates & Martin, 1993). Until quite recently, there were no reliable data on bluefish spawning in the Black Sea, but Gordina & Klimova (1996) showed that bluefish spawned throughout the Black Sea from june to September at temperatures frbm 20° to 26°C. Sabates and Martin (1993) stated that the northern limit of the geographic distribution of bluefish in the Mediterranean is the Catalan coast, but the find­ings of bluefish specimens in the Tar Cove (Mirna estu­ary-northern Adriatic) could not support this statement. It should be emphasised that in 1998 the eastern Adriatic was characterised by some interesting records of thermophilic species more northerly, for example, species Ruvettus pretiosus (Bettoso & DulciC 1999) in the Gulf of Trieste. An unusual occurrence of such rarely found fish could be related to the changes in climate and/or oceanographical conditions (Quigley, 1985; Dulcicf et al1999). The penetration and occurrence of both species might be connected with some special cli­matologicaf and oceanographical conditions and input of intermedian waters (50-100 m) in the central Adriatic, which influenced the increase in salinity and tempera­ture. Pallaoro (1988) also stated that the Adriatic ingres­sions caused more rare species to appear in the central Adriatic region in the 1986-87 period. As quoted by Harmelin (1991), some species with southern affinities {Serbia dumerili, Diplodus cervinus, Batistes carolirieri­sis, Epinephelus alexandrinus) are being found more commonly along the northwestern Mediterranean coasts, juveniles of these species were observed at rela­tively high latitudes, such as Calvi and Barcelona. Changes in the physical properties of the water and natural fluctuations in space and time are perhaps re­sponsible for the mentioned occurrences (Safdanha, 1992). The status of the bluefish and butterfish needs to be evaluated on a continuous basis because it is becom­ing increasingly apparent that uncommon species, and particularly those on the edge of their distribution, can be essential indicators of environmental change (Swabby & Potts, 1990). 21 ANNALES • Ser. hist. nat. • 10 • 2000 • 1 (19) lakov DULČi Č et nI.-. OCCUftRENCE O F BLUFFiSH, POMATOMUS SALTATORIUNNAIU5, 1766) 19-22 POJAVLJANJE MLADI C SKAKAVKE POMATOMUS SALTATOR (LiNNE, 1766) iN FIGE STROMATEUS FlATOLA (LiNNE, 1766) V VZHODNE M SREDNJEM JADRAN U Jakov DULČiC Armin PALLAORO & Miro KRALJEVIČ institut za oceanografijo inribištvo,HR-2100 0 Spiii, P.P. 500 POVZETEK Septembra 1999 so bile v bližini rta Čiovo (otok Čiovo, vzhodni srednji Jadran) ujete mladice skakavke Poma­tomus saltator, v/ bližini postaje Stončice (otok Vis, vzhodni srednji Jadran) pa mladice fige Strornateus fiatoia. Iz vzhodnega Jadrana doslej Se ni bilo zapisov o pojavljanju mladic teh ribjih vrst, čeprav je bilo med letoma i 975 in 1998 v vzhodnem Jadranu opravljenih že več Študij in raziskav o razvojnih stadijih mladic. Delo vsebuje tudi po­glavitne modometrične in meristične podatke. Ključne besede: Pomatomus saitator, Strornateus fiatoia, mladice, vzhodni jadran, prvo pojavljanje REFERENCES Bettoso, IM. & j. 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