Effects of depth, season and mesh size on the catch and discards of whiting ( merlangius merlangus euxinus) gillnet fishery in the southern black sea, Turkey

Bu çalışmada Türkiyenin Karadeniz kıyılarında mezgit (Merlangius merla ngus euxinus) solungaç ağı avcılığında, av ve ıskartayı etkileyen faktörler (derinlik, mevsim ve ağ göz açıklığı) incelenmiştir. Toplam 19 tür tanımlanmış ve hedef tür olan mezgit (Merlangius merla ngus euxinus) %87,56lık oranla toplam avın büyük bir kısmını oluşturmuş ve onu %6,32 ile barbunya (Mullus barbatus ) izlemiştir. Toplam av miktarının %82,02si ticari değer taşırken, %17,98inin ise ıskarta olduğu belirlenmiştir. Asgari avlanabilir boy olan 13 cm altında bulunan ve ıskarta edilen barbunya ve mezgit av miktarları sırasıyla %16,03 ve %13,27 olarak bulunmuştur. En y üksek ıskarta miktarının kış mevsiminde, en düşük ıskarta miktarının ise yaz mevsiminde olduğu görülmüştür. 55 -74 m derinlik grubunda ve 32 mm göz açıklığına sahip ağda ıskarta oranının en yüksek olduğu bulunmuştur. One -way analysis of similarity (ANOSIM) e göre ilkbahar ve yaz mevsimleri arasında, 32 -40, 32 -44 mm göz açıklıklarına sahip ağların ıskarta tür kompozisyonları arasındaki farklılıkların önemli olduğu belirlenmiştir (P

Güney Karadeniz de derinlik, mevsim ve ağ göz açıklığının mezgit ( merlangius merlangus euxinus) solungaç ağı avcılığında av ve ıskarta üzerine etkisi

In this study, factors (depth, season and mesh size) influencing the catch and discards of whiting ( Merlangius merlangus euxinus ) gillnet fishery on the Black Sea coasts of Turkey were investigated. A total of 19 species were identified and the target species, whiting (Merlangius merlangus euxinus ), dominated 87.56% of the total catch and followed by red mullet (Mullus barbatus ) with 6.32%. While 82.02% of the total catch had commercial value, 17.98% was discarded. The percentage of th e discarded red mullet and whiting under MLS (<13 cm) were found to be 16.03% and 13.27%, respectively. The highest discard amount was observed in winter and the lowest one in summer. The discard rate was highest in the 55 -74 m depth group and the 32 mm me sh size. One -way analysis of similarity (ANOSIM) showed that there were significant differences in the discard species compositions between spring and summer, as well as 32 and 40 mm, 32 and 44 mm mesh sizes (P<0.05). These results on the discard information in gillnet fishery can contribute to the literature on ecosystem -based sustainable fisheries management by highlighting relevant results on the protection of species and ecosystem.

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