Gökhan SUBAKAN, ALKAN ÖZTEKİN, İSMAİL BURAK DABAN, ADNAN AYAZ

Kuzey Ege Denizi'nde kupes uzatma ağlarında hedef dışı av olarak yakalanan bazı balık türlerinin seçiciliği

Bu çalışmada 20, 22, 23 ve 25 mm ağ göz genişliğine sahip kupes uzatma ağlarından yakalanan Melanur (Oblada melanura), Karagöz (Diplodus vulgaris), Isparoz (Diplodus annularis) ve Sarıkuyruk İstavrit (Trachurus meditterraneus) türlerinin uzatma ağı seçiciliği belirlenmiştir. Balikçilik denemeleri Mart 2008 - Şubat 2010 tarihleri arasinda Kuzey Ege Denizi'nde gerçekleştirilmiştir. Seçicilik parametreleri SELECT metot kullanılarak tahmin edilmiştir. En uygun seçicilik modelinin melanur (O. melanura) ve ısparoz (D. annularis) için log-normal, sarıkuyruk istavrit (T. meditterraneus) ve karagöz (D. vulgaris) için ise bi-modal olduğu belirlenmiştir. 20, 22, 23 ve 25 mm ağ göz genişliğinde optimum yakalama boyları sırası ile Isparoz (D. annularis) için 11.15, 12.27, 12.83 ve 13.94 cm, Karagöz (D. vulgaris) için 11.26, 12.39, 12.95 ve 14.08 cm, Melanur (O. melanura) için 15.3, 16.83, 17.59 ve 19.12 cm ve sarıkuyruk istavrit (T. mediterraneus) için 26.68, 29.35, 30.68 ve 33.35 cm olarak tespit edilmiştir. Bu sonuçlar Kuzey Ege Denizi'nde kupes avcılığında kullanılan uzatma ağlarında 23 mm ağ gözü genişliğinden daha büyüğünün kullanımının sürdürülebilir avcılık açısından önemli olduğunu ortaya çıkarmıştır.

Selectivity of some fish species caught as bycatch by bogue gillnets around North Aegean Sea

In this study, gillnet selectivity of saddled seabream (Oblada melanura), common two-banded seabream (Diplodus vulgaris), annular seabream (Diplodus annularis) and Mediterranean horse mackerel (Trachurus meditterraneus) which were caught by bogue gillnets with 20, 22, 23 and 25 mm mesh size (nominal bar lenght) have been determined. Fishing trials were carried out in Noth Aegean Sea from March 2008 to February 2010. Selectivity parameters were estimated using the Select method. Most suitable selectivity models were calculated as log-normal for saddled seabream (O. melanura) and annular seabream (D. annularis), bimodal for Mediterranean horse mackerel (T. meditterraneus) and common two-banded seabream (D. vulgaris). Optimum catch lengths for 20, 22, 23 and 25 mm mesh size were 11.15, 12.27, 12.83 ve 13.94 cm for annular seabream (D. annularis), 11.26, 12.39, 12.95 and 14.08 cm for common two-banded seabream (D. vulgaris), 15.3, 16.83, 17.59 and 19.12 cm for saddled seabream (O. melanura) and 26.68, 29.35, 30.68 and 33.35 cm for Mediterranean horse mackerel (T. mediterraneus), respectively. These findings may help us to understand that using higher than 23 mm stretched mesh size with gillnets which have been used for commercial bogue fisheries around north Aegean Sea is important for sustainability of fisheries.

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