CELALETTİN AYDIN, ZAFER TOSUNOĞLU, Adnan TOKAÇ

Dip trol ağlarında boy seçiciliğinin ızgara sistemleri ile geliştirilmesi

Tür ve boy seçiciliğinde deneme amaçlı kullanılan seçicilik ızgaraları, dip trol avcılığında boy seçiciliğine katkılar getirebilir. Bu amaçla yüksek ağız açan bir dip trol ağının torba kısmına, 20 ve 15 mm çubuk (bar) aralığına sahip 60° ve 120° açılarda seçicilik ızgaraları yerleştirilmiştir. Plastik (polietilen) çubuklardan oluşan seçicilik ızgralan ahşap malzeme ile çerçevelendirilmiştir. Izgara sistemlerinin seçicilikleri, dip trolü av kompozisyonu içinde en fazla miktarda çıkan barbunya (Mullus barbatus Linnaeus, 1758) ve ısparoz (Diplodus annularis Linnaeus, 1758) türleri üzerinde araştırılmıştır. 15 ve 20 mm çubuk aralığında 60° ve 120° açı ile yerleştirilen tüm ızgara sistemleri, barbunya ve ısparoz için aşın bir seçicilik göstermiştir. Özellikle 20 mm çubuk aralığına sahip sistemlerden en yüksek sonuçlar alınmıştır. Izgara yerleştirme pozisyonuna göre, 60° açılı sistemler 120° açılı sistemlere göre barbunya ve ısparozda daha başarlı bulunmuştur. Izgara sistemlerinden elde edilen seçicilik sonuçlan, farklı göz genişliği ve şekline sahip torba ağ gözleriyle yapılan denemelere göre daha yüksektir. Kaygan ve pürüzsüz bir yüzeye sahip plastik çubuklar arasından kaçan yavru balıklann yaşama şansı ağ gözlerinden kaçanlara oranla daha yüksek olacaktır.

Anahtar Kelimeler:

balıkçılık, tuzak ağlar, balık avlama ekipmanı

Improvement of size selectivity of bottom trawl nets by using grid systems

: Improvement of size selectivity of bottom trawl nets by using grid systems. Sorting grids used at length and species selection for experimental purpose can contribute to length selection at bottom trawl fishing. For this aim, sorting grids which has a grid bar space 20 and 15mm, were installed 60° and 120° angle attach at the part of cod-end of the high opening bottom trawl. Sorting grids made from plastic (Polyethylene) were framed wooden material. Selectivity of the grid systems was examined with the species of red mullet (Mullus barbatus Linnaeus, 1758) and annular sea bream (Diplodus annularis Linnaeus, 1758), which has caught the greatest amount in bottom trawl catch composition. AH systems 20mm and 15mm bar spaces were installed 60° and 120° angle attach have shown an excessive selectivity for red mullet and annular sea bream. Particularly, the highest results were taken from the systems which bar space is 20 mm. According to grid installation, 60° angle attacks systems were found more successful than 120° angle attach systems on red mullet and annular sea bream. Further more results which obtained from grid systems are higher than the selectivity experiments of different mesh size and shape. The survival of the young fish which escaped through space of plastic bars which has slippery and smooth exterior surface to be higher than net meshes.

Keywords:

fisheries, nets, fishing gear,

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