Comparison of CPUE, Size Distribution and Bycatch Rates of Gill and Trammel Net Used for Supplying Bait to Setline Fishing

Abstract

Within the scope of this study, 15 experimental fishing operations were carried out from the beginning of March 2020 until mid-June of the same year, to compare the gill net and trammel nets (16mm gill net, 16mm gill net and 18mm trammel net) used to supply bait to the setline fishing. The results obtained showed that the dominant species for both 16mm gill net and 16mm trammel nets was Chelon auratus. There were no statistically significant differences between the two types of nets in terms of CPUE (number/operation), average length and length distribution (p>0,05). It was determined that 41% of all individuals caught in gill nets and 44% of all individuals caught in trammel nets were bycatch species. When 16mm and 18mm trammel nets were compared with respect to catch composition, the dominant species for these two mesh widths was Chelon auratus, and the difference between the two mesh widths in terms of CPUE was not statistically significant (p>0,05), but the difference was statistically significant in terms of average length and length distribution (p<0,05). The rate of non-target species caught in 16mm and 18mm trammel nets was determined to be 41% and 22%, respectively. It was determined that the number of fishing hooks (fishing power) used in a season in professional fishing gear fishing was 67553 pieces. This data also approximated the number of mullets (approximately 3.3 tons) used as bait in Yumurtalık Bay in a season. As a result, the rate of bycatch in bait fishing with gillnets is remarkable and it is recommended to conduct studies on the survival rate of bycatch species released back into the sea. In addition, it is recommended to investigate the potential of substituting mullets which can be used as human food with artificial baits.

Keywords

• yumurtalık bay
• bycatch
• set line fishing
• bait
• chelon auratus