Effect of steel wire and claw size on the sea snail ( Rapana venosa ) catch in a Black Sea beam trawl fishery

Abstract

The effects of the claw size used on the shoes of the traditional sea snail beam trawl and the effect of the steel wire used between the shoes on catching efficiency were investigated on the Samsun coast of the Black Sea. A traditional beam trawl with steel wire and with a claw length of 5.5 cm (T) was compared to modified beam trawls with steel wire (M1) and without steel wire (M2) with a claw size of 0.5 cm. The operations were performed as T-M1 and then T-M2 hauls using the dual parallel towing method. There was no significant difference in the amount of target species in the comparison of T (70.12) and M1 (63.23) according to the average catch per unit effort (CPUE, kg h -1 ) values obtained (P = 0.399). In the T-M2 comparison, 49% higher CPUE value was achieved with the T (77.37) beam trawl and there was a significant difference in terms of targeted species (P = 0.002). As a result, it was observed by underwater observations that steel wire on the beam trawl had a negative effect on the ground, and it was found that the bycatch ratio with the T beam trawl was higher than that with the modified beam trawl.