CELALETTİN AYDIN, Adnan TOKAÇ, ZAFER TOSUNOĞLU

Yatay çubuklu seçicilik ızgarası ile bakalyaro (Merluccius merluccius), barbunya (Mullus barbatus) ve ısparoz (Diplodus annularis) seçiciliği

Bu çalışmada, 35 mm yatay çubuk aralığına sahip seçicilik ızgarası ile bakalyaro (M. merluccius L., 1758), barbunya (M. barbatus L., 1758) ve ısparoz (D. annularis L.,1758) seçiciliği araştırılmıştır. Denemeler geleneksel trol ağı (600 göz) ile Ege Denizi’nde Nisan 2003’de gerçekleştirilmiştir. Seçicilik ızgarası tünelin arka kısmına monte edilmiştir. Seçicilik ızgarasının önünde ve üst torbada kalan bireylerin toplamı ile ızgaradan kaçan bireyler, seçiciğinin tahmininde kullanılmıştır. Seçicilik verileri örtü torba yöntemi gibi logit fonksiyonun maksimum olabilirlik yöntemi ile analiz edilmiştir. Ortalama seçicilik eğrisi, bireysel çekimler arası varyasyon göz önüne bulundurularak tahmin edilmiştir. Ağırlık olarak toplam avın %56’sı yakalanmış, %44’ü kaçmıştır. Ortalama L50 değeri bakalyaro, barbunya ve ısparoz için sırasıyla 24,7cm ±1,1, 11,7 cm ±0,1 ve 15,4 cm ± 0,1 olarak bulunmuştur. 35 mm yatay bar aralığına sahip seçicilik ızgarası bakalyaro için ağ gözü büyüklüğü ve şekli ile diğer dikey ızgara tasarımıyla karşılaştırıldığında oldukça iyi seçicilik yüksek L50 değeri vermiştir. Bununla birlikte bu tasarım ısparoz için aşırı, barbunya içinse düşük seçicilik göstermiştir.

Anahtar Kelimeler:

balık avlama ekipmanı, bakalorya, balık avlama, Merluccius merluccius

Selectivity of sorting grid with horizontal bar for hake (Merluccius merluccius), red mullet (Mullus barbatus) and annular sea bream (Diplodus annularis

Selectivity of sorting grid with horizontal bar for hake (Merluccius merluccius), red mullet (Mullus barbatus) and annular sea bream (Diplodus annularis). In this study, selectivity of sorting grid which has 35 mm horizontal bar spacing was investigated for hake (M. merluccius L., 1758), red mullet (M. barbatus L., 1758) and annular sea bream (D. annularis L., 1758). Experiments were carried out in the İzmir Bay, Aegean Sea in April 2003 with a traditional bottom trawl net (600 mesh around the mouth). Sorting grid was attached aft belly of the net. The fish totally retained in front of the grid and collected upper part, and escaped from the grid were used to estimate the selectivity. Selectivity data analyzed as covered cod end method by means of a logit function of Maximum Likelihood Method. The mean selectivity curves were estimated from the individual hauls which were fitted taking into account the between haul variation. The percentages of the total catch in terms of weight were 56 %retained and 44 %escaped. Mean L50 value of hake, red mullet and annular sea bream were found as 24.7 cm ± 1.7, 11.7 cm ± 0.1 and 15.4 cm ± 0.1, respectively. 35 mm horizontal bar spacing showed substantially higherL50 value for hake regarding MLS compared to the mesh size and shape, and other vertical grid designs. However, this design shows over selectivity for annular sea bream and lower selectivity for red mullet.

Keywords:

fishing gear, hake, fishing, Merluccius merluccius,

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