Abstract
This study aims at improving fishery management by testing and comparing the
size selectivity and exploitation pattern of diamond-mesh codends, with mesh
sizes ranging from 25 to 54 mm, for cocktail shrimp (Trachypenaeus
curvirostris) in the South China Sea (SCS). Beginning from 25 mm, the
minimum mesh size regulated by the shrimp trawl fishery industry, we
investigated how the mesh sizes of the codends would affect the size
selectivity and exploitation pattern in reference to the minimum conservation
reference size (MCRS, 7.0 cm total length) of cocktail shrimp in the SCS.
According to our results, the selective properties of the codend mesh sized
at 25 mm in line with the regulation failed to protect the undersized individuals
of cocktail shrimp because of its 50% retention length of 5.85 cm (confidence
interval, CI: 5.16–6.18 cm), far less than the MCRS of cocktail shrimp. As the
retention probability of a shrimp with a MCRS length was as high as 97.45 % (CI:
86.86–100.00%), more than 40% of the undersized shrimp was retained. It was
proved that increasing the codend mesh size did not significantly improve the
size selectivity and exploitation pattern which might be improved by other
gear modifications.
size selectivity and exploitation pattern of diamond-mesh codends, with mesh
sizes ranging from 25 to 54 mm, for cocktail shrimp (Trachypenaeus
curvirostris) in the South China Sea (SCS). Beginning from 25 mm, the
minimum mesh size regulated by the shrimp trawl fishery industry, we
investigated how the mesh sizes of the codends would affect the size
selectivity and exploitation pattern in reference to the minimum conservation
reference size (MCRS, 7.0 cm total length) of cocktail shrimp in the SCS.
According to our results, the selective properties of the codend mesh sized
at 25 mm in line with the regulation failed to protect the undersized individuals
of cocktail shrimp because of its 50% retention length of 5.85 cm (confidence
interval, CI: 5.16–6.18 cm), far less than the MCRS of cocktail shrimp. As the
retention probability of a shrimp with a MCRS length was as high as 97.45 % (CI:
86.86–100.00%), more than 40% of the undersized shrimp was retained. It was
proved that increasing the codend mesh size did not significantly improve the
size selectivity and exploitation pattern which might be improved by other
gear modifications.