Comparison of the commerical and alternative codends catch composition in the Western Black Sea trawl fishery

In this study, the catch composition, Catch per Unit Effort (CPUE), species diversity and length frequency of the commercial trawl codend (40mmD) and alternative trawl codend (44mmD, 40mmS and 40mmT90) used in bottom trawl fishing in the Black Sea were compared. During the study, a total of 64104 individuals (701.13 kg) belonging to 33 species were obtained which were 19 bony fish, 2 cartilaginous fish, 4 crustaceans, 5 mollusks, 1 echinoderm, 1 tunicate and 1 porifera. The highest number of species was obtained in the 40mmD trawl codend (28 species), and the lowest number of species was obtained in the 40mmT90 trawl codend (22 species). The CPUE values were 40.22±6.04 kg/h for 44mmD codend, 66.66±13.00 kg/h for 40mmD codend, 45.55±7.34 kg/h for 40mmS codend and 26.12±3.60 kg/h for 40mmT90 codend. The highest CPUE value for whiting was 28.75±15.56 kg/h in 40mmD trawl codend, while the highest CPUE value for red mullet was 4.83±2.62 kg/h in 44mmD trawl codend. The difference between the CPUE values of the fishes caught in trawl codends was analyzed with the t test, the difference between 40mmD - 40mmS and 40mmD - 40mmT90 trawl codends for whiting was significant, the difference between 44mmD - 40mmT90 and 40mmD - 40mmT90 trawl codend for red mullet and total catch was found to be significant (p<0.05). The differences were significant (p<0.05) between the length distribution of whiting and red mullet caught in the four trawl codends. It is important for sustainable fishing that the characteristics of the fishing gear which targeted multi species in the fishery, must have regulated according to the characteristics of the targeted fishes in the region