Exploitation and mortality rates of E uropean hake ( M erluccius merluccius ) in the A egean S ea ( I zmir B ay, T urkey)

Summary Experimental trawl surveys in I zmir B ay ( A egean S ea) were taken seasonally between 2007 and 2009. A total of 1353 specimens were sampled ranging from 5.9 cm (1.4 g) to 44.4 cm (670 g). The main size group of M erluccius merluccius was between 14 and 25 cm total length ( TL ). In total, the mean catch per unit effort ( CPUE ) for hake by number and weight was 101.4 ± 18.4 ind h −1 and 10.7 ± 1.5 kg h −1 , respectively. Highest mean CPUE by number and biomass was determined as 257.1 ± 15.1 ind h −1 and 15.1 ± 4.9 kg h −1 in summer. Mortality ( M , F , Z ) ratios of hake were 0.58 year −1 , 1.66 year −1 and 2.24 year −1 , respectively. Because of the many smaller specimens caught in this study, this seems to indicate that there may be heavy fishing pressures on the hake population; the high exploitation rate ( E  = 0.74) appears to confirm this conclusion.