Selectividad de artes de enmalle (betas y trasmallo) en el Egeo septentrional, Turquía

Abstract

Fishing trials were carried out with gill nets and trammel nets in the northern aegean Sea from March 2004 to February 2005. Four different mesh sizes for the gill nets and the inner panel of trammel nets (16, 18, 20 and 22 mm bar length) were used. Selectivity parameters for the five most economically important species, bogue (Boops boops), annular sea bream (Diplodus annularis), striped red mullet (Mullus surmuletus), axillary sea bream (Pagellus acarne) and blotched picarel (Spicara maena), caught by the two gears were estimated. the SeLeCt method was used to estimate the selectivity parameters of a variety of models. Catch composition and catch proportion of several species were different in gill and trammel nets. the length frequency distributions of the species caught by the two gears were significantly different. the bi-modal model selectivity curve gave the best fit for gill net and trammel net data, and there was little difference between the modal lengths of these nets. However, a clear difference was found in catching efficiency. the highest catch rates were obtained with the trammel net. Given that many discard species and small fish are caught by gill nets and trammel nets with a mesh size of 16 mm, it is clear that these nets are not appropriate for fisheries. Consequently, the best mesh size for multispecies fisheries is 18 mm. this mesh size will considerably reduce the numbers of small sized individuals and discard species in the catch.

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“…The selection curves of the different mesh sizes were been shaped with uniform height, a fact that is also found in other studies (Baranov, 1914;Amarasinghe, 1988;Karakulak & Erk, 2008). Th is was in accordance with the present study.…”

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“…The Kolmogorov-Smirnov (K-S) test was used to determine differences between size frequency distributions of fish caught by hooks of varying sizes (Siegel and Castellan, 1989;Karakulak and Erk, 2008;Aydın, 2011).…”

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“…In the study conducted on bouge on Gökçeada coasts, Karakulak and Erk (2008) estimated the modal Karakulak and Erk (2008) because of the close study areas. On another study conducted on bouge, Kale (2008) calculated the optimum catch lengths as 22.37 and 25.42 cm, respectively with E = 0.50 gillnet, 44 and 50 mm mesh sizes.…”

“…The possibility of catching by tangling is increasing by the decreased hanging ratio of gillnets (Karlsen and Bjarnason, 1986). The studies on selectivity have mostly emphasized the effect of mesh size on the selectivity of species (Petrakis and Stergiou, 1996;Psuty and Borowski, 1997;Santos et al, 1998;Madsen et al, 1999;Fujimori and Tokai, 2001;Fabi et al, 2002;Özekinci et al, 2003;Park et al, 2004;Fonseca et al, 2005;Dinçer and Bahar, 2008;Karakulak and Erk, 2008;Acarlı et al, 2013). The mesh size is detected as the main factor that affects the selectivity (Von Brandt, 1975).…”