A Study on the Bony Fishes Caught in the South of the Sea of Marmara by Bottom Trawling and their Morphologies

Turk J Zool 25 (2001) 323-342 © TÜB‹TAK A Study on the Bony Fishes Caught in the South of the Sea of Marmara by Bottom Trawling and their Morphologies Lütfiye Soyal ERYILMAZ Department of Biology, Faculty of Science, University of Istanbul, Istanbul - TURKEY Received: 07.06.2000 Abstract: A total of 572 specimens of bony fish were obtained as a result of bottom trawling at 47 stations by R/V Arar of the University of Istanbul at the south of the Sea of Marmara, in 1992 and 1995. Upon analysis of these specimens, it was revealed that 49 bony fish species, including 5 subspecies, belonging to 30 families were found, and their diagnostic characteristics, the place and the depth where they were caught are given. The presence of Alosa pontica (Eichwald, 1838), known from the Black Sea, was determined in the Sea of Marmara in this study. The majority of fishes in terms of quantity caught by bottom trawling is composed of 9 economically important species and 6 economically unimportant species, and the rest are in the group of species with few individuals. Key Words: Bony Fishes, Sea of Marmara, Bottom Trawl, Morphology. Marmara Denizi’nin Güneyinde Dip Trolu ile Yakalanan Kemikli Bal›k Türleri ve Morfolojileri Üzerinde Bir Araflt›rma Özet: 1992 ve 1995 y›llar›nda ‹stanbul Üniversitesi Arar Araflt›rma Gemisi ile yap›lan 47 dip trolu çekiminden elde edilen toplam 572 örne¤in incelenmesi sonucunda Marmara Denizi’nin güneyinde, 30 familyaya ait, 5’i alt tür olmak üzere 49 kemikli bal›k türü yakalanm›fl ve bunlar›n tan›nma özellikleri ile yakaland›klar› yer ve derinlikler verilmifltir. Karadeniz’den bilinen Alosa pontica (Eichwald, 1838)’n›n Marmara Denizi’ndeki varl›¤› bu çal›flma ile saptanm›flt›r. Trollerde yakalanan bal›klar›n, miktar olarak çoklu¤unu ekonomik öneme sahip 9 tür ve ekonomik önemi olmayan 6 tür oluflturmakta, di¤erleri bireyce az olan türler grubuna girmektedir. Anahtar Sözcükler: Kemikli Bal›klar, Marmara Denizi, Dip Trolu, Morfoloji. Introduction The Sea of Marmara is an inland sea that separates Europe from Asia, and is joined to the Black Sea by the Bosphorus and to the Aegean Sea by the Dardanelles. For this reason, the characteristics of the Sea of Marmara are influenced by two neighboring seas. Though the Sea of Marmara has the smallest surface area and volume of the seas surrounding Turkey, it holds the second position, after the Black Sea, in terms of fishing. Research on the sea fauna along the coasts of Turkey was initiated by foreign researchers at the beginning of the 20th century and entered an intensive stage with the participation of Turkish researchers in the 1940s. However, the fish fauna of the Turkish seas has still not been fully determined. Among the researches on the fish fauna in the Sea of Marmara are by Ninni (1), Devedjian (2), Sözer (3), Erazi (4, 5, 6, 7), Kosswig (8), Akfl›ray (9), Nümann (10, 11), Demir et al. (12), Slastenenko (13), Demir (14, 15), Atl› (16), Türgan (17), Erman (18, 19, 20, 21), Demir (22), Geldiay and Mater (23), Mengi (24), Ünsal (25, 26), Meriç (27, 28), Whitehead et al. (29, 30), Akfl›ray (31), Fischer et al. (32), Mater et al. (33), Benli et al. (34), Kocatafl et al. (35), Meriç (36, 37), Mater and Meriç (38), Ünsal and Oral (39), Uysal et al. (40) and Meriç et al. (41). In addition to these, the presence of some fish species in the Sea of Marmara has been confirmed by research on fish eggs and larvae (Demir and Ar›m (42), Ar›m (43), Demir (44, 45, 46, 47, 48), Altun (49)). The Aegean Sea waters pass through the Dardanelles and flow into the Sea of Marmara at a 20 m depth, and show the characteristics of the Mediterranean water with 323 A Study on the Bony Fishes Caught in the South of the Sea of Marmara by Bottom Trawling and their Morphologies its 38-39‰ salinity (50). Black Sea waters with low salinity coming through the Bosphorus mix with the surface waters of the Sea of Marmara and meet with a gradual increase in salinity. The salinity of the Black Sea waters in the northern Marmara is around 22‰ (51). examining the morphologies of these fish with regard to taxonomy. Fishes in the Sea of Marmara provide good fishing during migrations for feeding, spawning and wintering between the Aegean Sea and the Black Sea through the system of straits. After 1980, a substantial increase is observed in fishing, the number of fishing boats and their capacities (35). Although this increase initially generated a positive effect, later on it negatively affected the fishing due to the significant decrease in the yield per boat. In addition, the rise in pollution in the Sea of Marmara because of the increase in land development projects, discharge of domestic and industrial wastes into the sea, gradual increase in international maritime transport and the arrival of polluted waters of the River Danube to the Sea of Marmara by way of the Black Sea and the Bosphorus caused a decrease in yield in fishing. Therefore, it is necessary to determine the fish species in the Sea of Marmara caught by means of coastal fishing, medium depth trawl, large bag nets and bottom trawl, and biologically examine the economically significant ones among these species, determine the sea stock amounts and reorganize fishing accordingly. For the purpose of determining the species of bony fishes, specimens of fish were obtained in various seasons of 1992 and 1995 by bottom trawling performed at the places shown in Figure in the south of the Sea of Marmara, by the Arar research vessel of the University of Istanbul. Bottom trawling was performed at a total of 47 stations, at depths of 27-164 m. The dates on which work was done at the stations, station codes, periods of drawing the trawl depths, and locations are given in Table. This study was conducted for the purpose of determining the species of bony fishes caught by bottom trawling in the south of the Sea of Marmara and 27° 28° The obtained specimens of fish were fixed and preserved in 5% formaline. The colors of the fish were assessed through work on fresh specimens. In order to determine the genus, species and subspecies of fish samples brought to the laboratory, examinations were done on metric and meristic characteristics. During the analysis of the fish, the taxonomic order suggested by Nelson (52), species names suggested by Fischer et al. (32), Whitehead et al. (29, 30), Wheeler (53), Golani (54) and Eschmeyer (55), and the English common names sugested by Whitehead et al. (29, 30) and Wheeler (53) were used. Laevastu’s (56) method was employed for the metric measurement of the dimensions, and compass and millimetric measurement board were 29° Silivri 41° Materials and Methods Figure: ‹STANBUL 41° TEK‹RDA⁄ Mürefte 4 1 28 Gelibolu 27 13 37 18 41 42 15 40 19 43 16 39 20 44 38 17 21 12 35 14 34 24 6 29 46 7 30 33 23 Karaburun 31 3 Erdek 10 45 Kurflunlu Karabiga 8 345112 Band›rma Karacabey 32 Bozlar bo¤az› Karacabey ÇANAKKALE ‹zmit 26 25 Gölcük YALOVA Bozbu (...truncated)