Size selection and exploitation pattern of diamond mesh codends with different mesh sizes in demersal trawl fishery for banded scad (Caranx (Atule) kalla) in the South China Sea

Abstract

Size selection and exploitation pattern of diamond-mesh codends with different mesh sizes, 25 to 54 mm, for demersal trawl fishery targeting banded scad (Caranx (Atule) kalla) was tested and compared using the covered codend method in the South China Sea. Our results demonstrated that the selective parameters, L50 (50% retention length) and SR (selection range), would increase as the mesh sizes of codends increased, and the confidence intervals in these parameters became relatively wider when the mesh sizes increasing to 40 mm. The results of exploitation pattern showed that catch efficiency of codends would decrease when the mesh sizes increased. Considering compromise of protecting juvenile fish and the profitability of fishermen, the codend with 30 mm mesh size would be the best choice to target banded scad among all tested codends. Our study will be beneficial to the fishery management in the studied area.