Untitled

Abstract

The modification of the trawl codends to reduce the capture of juvenile fish increasing of fishing gear selectivity has been one of the management tools for sustainable fisheries. This study were examined the effect of square mesh escape panel installation on selectivity of demersal trawl codends for whiting (Merlangius merlangus euxinus, N.) in the Black Sea. Codend mesh selectivity experiments were carried out using 40 mm nominal diamond mesh PE codend with 36 mm and 40 mm mesh size square mesh escape window inserted in the forward part of the top panel. The experiments were carried out in the southern Black Sea between February and March 2006 on a traditional fishing boat. A total of 6 valid hauls were made by using the hooped covered codend method. Selectivity parameters were calculated by using a logistic equation with the maximum likelihood method. Mean L 50 s and selection ranges of whiting were determined as 12.57 (se. 0.41) cm and 3.45 (se. 0.03) cm for 40 mm nominal diamond mesh, 12.71 (se. 0.45) cm and 3.12 (se. 0.03) cm for 36 mm square mesh panel and 13.55 (se. 0.32) cm and 3.70 (se. 0.02) cm for 40 mm square mesh panel, respectively. The results shows that the use of square mesh panel (40 mm) in the forward part of the top panel reduce the capture of juvenile fish and increases the demersal trawl codend selectivity.

Comparison of selectivity of the trawl codends for whiting (Merlangius merlangus euxinus) in the Black Sea

“…Ceylan et al, (2014) stated that some of the fishermen in the Black Sea are using small diamond mesh size in their trawl codends cause lower selectivity. In previous studies (Zengin and Düzgüneş, 1999;Özdemir et al, 2012), selectivity of whiting improved by the use of various type of square mesh codend (square mesh window and panels). Similar results were obtained in the present study (36S and 40S).…”

“…The General Fisheries Commission for the Mediterranean (GFCM) has supported scientists to carried out selectivity studies and investigate the biological and socio-economic effects of 40 mm square mesh and 50 mm diamond mesh in demersal trawl fleets (GFCM, 2010). Although most of the whiting are landed by demersal trawls in the Black Sea, there has a limited number of studies related to trawl selectivity according to the selectivity studies in other regions (Mediterranean and Aegean Sea) (Zengin and Düzgüneş, 1999;Özdemir et al, 2012). The use of optionally square mesh in the Black Sea is given to the fisherman by the Turkish Fisheries Regulations (Anonymous, 2016).…”