AHMET RAİF ERYAŞAR, HÜSEYİN ÖZBİLGİN, GÖKHAN GÖKÇE, Yeliz ÖZBİLGİN DOĞANYILMAZ, İSMET SAYGU, ADEM SEZAİ BOZAOĞLU, Ebrucan KALECİK

The effect of codend circumference on selectivity of hand -woven slack knotted codend in the north Eastern mediterranean demersal trawl fishery

El örmesi gevşek düğümlü torbanın zayıf seçiciliği ve yüksek ıskarta oranı Kuzey Doğu Akdeniz demersal balık stokları için ciddi bir problemdir. Bu çalışmada torba çevresindeki göz sayısının dip trol seçiciliği üzerine olan etkisi barbun (Mullus barbatus), kupes (Boops boops ), Nil barbunyası ( Upeneus moluccensis), merbun (Nemipterus randalli) ve izmarit (Spicara smaris) için araştırılmıştır. Mersin Körfezinde 08 Ekim ve 26 Aralık 2012 tarihleri arasında örtü torba yöntemi kullanılarak toplam 18 çekim gerçekleştirilmiştir. Sonuçlar test edilen türler için ticari olarak kullanılan standart torbanın (çevresinde 300 göz olan) seçiciliğinin çok zayıf olduğunu ve dar torbanın (çevresine göz sayısı 150 olan) seçiciliği önemli ölçüde arttırdığını göstermektedir. Bununla birlikte, dar torba beş ticari tür için minimum yakalanma boyu veya ilk üreme boyunun altındaki bireyleri kaçırmada yeterince s eçici değildir.

Kuzey Doğu Akdeniz demersal trol balıkçılığında torba çevresinin el örmesi gevşek düğümlü torba seçiciliğine etkisi

Poor selectivity and high discard rate of hand -woven slack knotted codend is a serious problem for north eastern Mediterranean demersal fish stocks. This study investigates the effect of codend circumference on bottom trawl selectivity fo r re d mullet (Mullus barbatus ), bogue (Boops boops ), goldband goatfish (Upeneus molu ccensis ), Randall's threadfin bream (Nemipterus randalli) and picarel (Spicara smaris ). A total of 18 valid hauls were conducted using covered codend method between 08 October and 26 December 2012 in Mersin Bay. Results show that selectivity of commercially used standard codend (300 meshes around its circumference) is rather poor and the narrow codend (150 meshes around its circumference) significantly increases selectivity for tested species. However, it is not selective enough to avoid the individuals of five commercial species under the MLS or FMS.

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