Length–Weight Relationship of some Discarded Fish Species with Emphasis on Length at Maturity from the Central Aegean Sea, Turkey

Abstract

In this study, length–weight relationships were estimated for discarded trawl fish species and mean size at capture was compared with reported mean length at first maturity (Lm). Sampling was conducted in Sigacik Bay, on the Turkish coast of the central Aegean Sea, between October 2008 and April 2010 onboard a commercial trawler fishing over a depth range of 88–450 m. A total of 14,120 individuals from 15 fish species belonging to 13 families were examined: 9 species were elasmobranchs and 6 were teleosts. Length-weight relationship (LWR) values of b parameter varied between 2.55 and 3.37, with five species having isometric growth, five negative and six positive allometric growth. LWR was not determined for one species due to insufficient sample size. Average size at capture for 14 fish species was found to be below the reported Lm. Our results could be useful in stock assessments and serve as a reference for future comparison of similar parameters estimated in other parts of the Aegean Sea or Mediterranean. Furthermore, information on the discard species in the trawl fishery, their mean size at capture and conservation status is important when considering sustainable ecosystem based fishery management.