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    Common sole, Solea solea (Linnaeus 1758) in Izmir Bay, Aegean Sea: A special morphometric approach to dimorphic structures
    (Iranian Fisheries Science Research Inst-Ifsri, 2023) Gurkan, S.; Taskavak, E.
    The Mediterranean is a significant region for marine (Yildiz et al., 2020) fish particularly flatfish species with high commercial value. The common sole, Solea sp. (Linnaeus 1758) is a flat fish species that has high commercial importance in Turkey as well as in the whole world. Turkey's most important sole fishing areas are Gulluk Bay, Karina and Izmir Bay in Aegean Sea (Uluturk et al., 2012). As known, morphological characteristics are crucial in defining species or subspecies and serve as the primary basis of systematic science (Chan, 2001). However, biometric characters' similarities or differences vary due to geographical variations (Ezzat et al., 1975). Therefore, understanding population characteristics and growth dimorphisms between sexes across various geographical areas is vital for these economically important flatfish species. Although studies on biological characteristics of Solea solea exist (Amara et al., 2007; Parma et al., 2019; Cerim and Ates, 2020), research on whether growth causes any morphometric differentiation in both sexes is insufficient, considering the length groups. This study aims to determine the dimorphism in growth and geographic characters in the S. solea, caught from the Aegean Sea off the coast of Turkiye, depending on sexes and length groups, using morphometric combinations, which are an integral part of biological studies.
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    Diet composition of Belone belone (Linnaeus, 1761) (Pisces: Belonidae) in the Aegean Sea
    (Wiley, 2009) Sever, T. M.; Bayhan, B.; Bilge, G.; Taskavak, E.
    P>The objective of this study was to determine the monthly dietary pattern in migratory garfish and to improve our understanding in the seasonality of prey choice. Gut contents of 597 Belone belone specimens collected from the eastern Aegean Sea (Turkey) were analyzed: 79.2% contained food in their guts and 20.8% had empty guts. Crustaceans (36.7%) were the most important prey with a 36.7 index of relative importance (%IRI). Especially brachyurans (13.0%) and copepods played a major role (10.1%), followed by teleosts (26.1%) and other food categories (23.3%) (much of which was of terrestrial origin, including insects). Nannocalanus minor, Clausocalanus arcuicornis, Temora stylifera, Labidocera wollastoni and Oncea media were important copepods found in the guts of B. belone specimens. Analysis of variance of the monthly weight data indicated no significant seasonal differences, except for January and February.
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    Diet composition of Belone belone (Linnaeus, 1761) (Pisces: Belonidae) in the Aegean Sea
    (Wiley, 2009) Sever, T. M.; Bayhan, B.; Bilge, G.; Taskavak, E.
    P>The objective of this study was to determine the monthly dietary pattern in migratory garfish and to improve our understanding in the seasonality of prey choice. Gut contents of 597 Belone belone specimens collected from the eastern Aegean Sea (Turkey) were analyzed: 79.2% contained food in their guts and 20.8% had empty guts. Crustaceans (36.7%) were the most important prey with a 36.7 index of relative importance (%IRI). Especially brachyurans (13.0%) and copepods played a major role (10.1%), followed by teleosts (26.1%) and other food categories (23.3%) (much of which was of terrestrial origin, including insects). Nannocalanus minor, Clausocalanus arcuicornis, Temora stylifera, Labidocera wollastoni and Oncea media were important copepods found in the guts of B. belone specimens. Analysis of variance of the monthly weight data indicated no significant seasonal differences, except for January and February.
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    A Preliminary Study on the Morphometric Features of the European Eel, Anguilla anguilla (Anguillidae) in Gediz Lagoon (Izmir Bay, the Aegean Sea): Special Emphasis to Sexual Dimorphism
    (2023) Gurkan, S.; Taskavak, E.; Taylan, B.
    Abstract: In this study, we aimed to state how we can contribute to an effective population management and protection by determining the morphometric characteristics of European yellow eels, Anguilla anguilla Linnaeus 1758, in the Aegean Sea population, Izmir Bay. It was found that the eye index and condition values of the female specimens are higher than those of the males. While it was determined that there was a significant difference between both sexes in 19 of 20 morphometric measurements of the head region, there was no statistical difference only in the height measurement at the nostril level of the head. In our study, the fact that specimens with ovaries were seen among the females longer than 34 cm (length group II) is remarkable in terms of early maturation in the region. The differences in head measurements between sexes indicate the existence of a dimorphic structure and these differences are in favor of female specimens. © 2024, Pleiades Publishing, Ltd.
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    A temporal approach for morphological indices of the common sole (Solea solea Linnaeus 1758) from the coast of the Aegean Sea, Turkey
    (Natl Inst Science Communication-Niscair, 2021) Gurkan, S.; Taskavak, E.; Engin, S.; Taylan, B.
    Temporal changes of the morphological indices (Relative Gut Length (RGL), Fullness Index (FI), Hepatosomatic Index (HSI), Visceral Index (VSI), Gonadosomatic Index (GSI) and Fulton condition)) in 122 (female: 94, male: 19, immature: 9) common sole were evaluated. Total length-weight relationships were calculated as W = 0.085TL(3.01) and W = 0.0547TL(2.40) in females and males, respectively, whereby isometric growth was observed in females and negative allometric growth was observed in males. While there was no statistically significant difference was observed between the FI, HSI, Viscerosomatic Index (VSI), RGL and GSI values of both sexes, however, there was a statistically significant difference in terms of Fulton K values (P < 0.05). In addition, there are statistical differences between the sexes total lengths and the values of RGL, FI, HSI, VSI, and Fulton-K (P < 0.05), as it is discernible in their HSI and VSI index values according to the month the specimens were obtained (P < 0.05). According to the results of the analysis, it has been determined that the female common sole along the Aegean coast adjust their energy temporally and store the energy they obtain from vegetative and carnivorous feeding. Contrary to the situation seen in females, the male individuals invest in energy through omnivorous feeding, according to the diet in the active process. Based on the results, it can be stated that the VSI and HSI are both important indicators of fish condition status. The results found here may be useful in both fishery research and fishery management.