Barbunya (Mullus barbatus L., 1758) ve ısparoz (Diplodus annularis L., 1758) için standart ve dar trol torbaların seçiciliği

Türkiye’deki, demersal balıkçılıkta kullanılan dip trol torbaları (40 mm PE) düşük seçicilik özelliğindedir. Bu yüzden dip trol ağlarında torba seçiciliğinin geliştirilmesi demersal balık stoklarının korunması bakımından önem kazanmaktadır. Bu çalışmada Ege Denizi’nde barbunya (Mullus barbatus) ve ısparoz (Diplodus annularis) balık türlerine ait, Türkiye dip trol balıkçılığında ticari olarak kullanılan standart torba (çevre göz sayısı 200) ve dar torbanın (çevresinde 200 göz yerine 100 göz olan) seçicilik özellikleri araştırılmıştır. Deniz çalışmaları İzmir Körfezinde 3 Haziran ve 27 Temmuz 2004 tarihleri arasında araştırma gemisi “Egesüf” ile yürütülmüştür. Veriler örtü torba tekniği kullanılarak elde edilmiş ve ‘En Yüksek Olabilirlik Yöntemi’ ile lojistik denklem kullanılarak analiz edilmiştir. Dar torba (L50=13,9 cm), barbunya için standart torbadan (L50=11,8 cm) daha yüksek bir ortalama L50 değeri göstermiştir. Buna karşın, Isparoz için torbaların ortalama L50 değerleri arasında önemli bir fark yoktur (p>0,05). Sonuç olarak, daraltılmış torba standart torba ile karşılaştırıldığında barbunya seçiciliğinde önemli iyileştirmeler sağladığı tespit edilmiştir.

Anahtar Kelimeler:

balık avlama, izmaritgiller, balık avlama ekipmanı

Selectivity of standard and narrow trawl codends for the red mullet (Mullus barbatus L., 1758) and annular sea bream (Diplodus annularis L., 1758)

Selectivity of standard and narrow trawl codends for the red mullet (Mullus barbatus L., 1758) and annular sea bream (Diplodus annularis L., 1758). The bottom trawl codends (40 mm PE) used in conventional Turkish demersal fisheries has rather poor selectivity. For this reason, the improvements of the codend selectivity in the bottom trawl nets get importance from the point of view to protect of demersal fish stocks. In this study, selectivity properties of standard codend (200 meshes around the circumference) conventionally used in Turkish bottom trawl fisheries and narrow codend (100 meshes instead of 200 meshes around the circumference) had been searched for red mullet (Mullus barbatus) and annular sea bream (Diplodus annularis) in the Aegean Sea. Sea trials were carried out in İzmir Bay between 3rd June and 27th July 2004 on board R/V “Egesüf”. Data were collected using the covered codend technique, and analyzed by means of a logistic equation with the maximum likelihood method. For the red mullet, it was shown that the narrow codend (L50=13.9 cm) was higher an average L50 values than the standard codend (L50=11.8 cm). However, there was no significant difference between average L50 values of the codends for the annular sea bream (p>0.05). As a consequence, it was determined that the narrowed codend compared to standard codend provided considerable improvements for the selectivity of red mullet.

Keywords:

fishing, sea bream, fishing gear,

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