Can Ali KUMOVA, UĞUR ALTINAĞAÇ, ALKAN ÖZTEKİN, ADNAN AYAZ, Alparslan ASLAN

Effect of Hanging Ratio on Selectivity of Gillnets for Bogue (Boops boops, L 1758)

Bu çalışma Kasım 2011- Ocak 2013 tarihleri arasında, Çanakkale kıyılarında ticari avcılıkta yaygın olarak kullanılan 36, 40, 44 ve 50 mm göz uzunluğuna sahip kupez galsama ağları üzerine gerçekleştirilmiştir. Donam faktörünün seçiciliğe etkisini belirlemek amacıyla, ağlar üç farklı donam faktörü ile donatılmıştır. Seçicilik hesaplamalarında SELECT metodundan yararlanılmıştır. Beş farklı modelden (normal location, normal scale, gamma, lognormal, bimodal) elde edilen sonuçlara göre kupes balığı için en iyi sonucu lognormal model vermiştir. 36, 40, 44 ve 50 mm göz genişliğine sahip ağların lognormal modele göre optimum yakalama boyları; 0.4 donam faktörüyle donatılan ağlarda sırasıyla 18.65, 20.72, 22.80 ve 25.90 cm; 0.5 donam faktörüyle donatılan ağlarda sırasıyla 17.90, 19.89, 21.88 ve 24.86 cm; 0.6 donam faktörüyle donatılan ağlarda sırasıyla 16.98, 18.87, 20.75 ve 23.58 cm olarak hesaplanmıştır. Denemelerde elde edilen optimum yakalama boyları kupez balığının ilk üreme boyundan oldukça yüksek olduğu görülmüştür. Sonuçlar araştırmada kullanılan ağların kupez balıklarının stoğu üzerine baskı yapmadığını göstermiştir. Çalışmada donam faktörünün diğer faktörlerin yardımıyla birlikte seçiciliği etkilediği belirlenmiştir. Bundan dolayı donam faktörü seçiciliği etkileyen diğer faktörlerle birlikte hesaba katılması gerekmektedir

Kupez (Boops boops, L. 1758) Balığı Avcılığında Galsama Ağlarının Seçiciliği Üzerine Donam Faktörünün Etkisi

This study was conducted between November 2011 - January 2013 on Bogue gill nets in mesh size of 36, 40, 44 and 50 mm targeting bogue (Boops boops, L. 1758), which is used in commercial fishing commonly at Çanakkale shores. The bouge nets were rigged in three varying hanging ratios (E=0.40, E=0.50, E=0.60) with the purpose of determining the effect of hanging ratio to selectivity. SELECT (Share Each Lengthclass Catch Total) method was used to fit selectivity curves. Lognormal model gave the best fit for selectivity curve of bogue selection according to the findings obtained from five different curve models (normal location, normal scale, gamma, lognormal, bimodal). According to the lognormal method modal lengths of bogue nets in mesh size of 36, 40, 44 and 50 mm, following findings were obtained; in hanging ratio of 0.4, rigged nets are 18.65, 20.72, 22.80 and 25.90 cm, respectively; in hanging ratio of 0.5, rigged nets are 17.90, 19.89, 21.88 and 24.86 cm, respectively; in hanging ratio of 0.6, rigged nets are 16.98, 18.87, 20.75 and 23.58 cm, respectively. Model lengths of bogue nets that were used in field studies are quite higher than the first reproduction length. The results show that the nets used in research have no pressure on bogue stock. It was determined that the hanging ratio may affects the selectivity with the help of other factors. It is taken into account the hanging ratio together with the other factors affect the selectivity

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