Catch composition and discard of the boat seine in the İstanbul Strait (Turkey)

This study attempted to determine certain characteristics of the species caught in the boat seine fishery in the Istanbul Strait during the 2009-2010 fishing season, including catch composition, commercial and nontarget catch ratios, catch per unit effort (CPUE), and the length distributions of commercial species. A survey of 20 boat seine operations detected species belonging to the following 3 different taxonomic groups: 26 Osteichthyes, 2 Crustacea, and 1 Mollusca. Of all of the nontarget species, 13 were commercial, 14 were noncommercial, and only 1 was under threat. Of the total catch, the proportion of the commercial species in the nontarget catch was 31.3%, and that of the discarded catch, which the fishermen did not take into account, was 2.8%. According to the Spearman rank correlation test, there was a significant correlation between the total catch and the discarded catch (r = 0.759); the size of discarded catch increased as the catch increased (P = 0.000). It was clear from the data that overfishing was seen in the commercial species.