Quantitative Assessment and Temporal Fluctuation of a Multiday Shrimp Trawl Bycatch off Digha Coast, West Bengal, India

Assessment of Bycatch from a Shrimp Trawler off Digha Coast

Abstract

Bycatch is one of the main issues affecting marine
 fisheries globally, and attempts have been made to
 understand the issue of bycatch at different scales.
 In India the bycatch issues in trawling have been
 reported widely. However, there are only scarce
 reports from northeast coast of India. The current
 study was carried out between July 2018 and March
 2019 to assess the faunal composition, quantity of
 trawl bycatch and its seasonal fluctuation from a
 commercial multiday shrimp trawl (targeting
 shrimps and lobsters) operated along inshore areas
 off the Digha coast, West Bengal, India. Out of 145
 finfish and shellfish species recorded, 130 species
 (104 species retained and 26 species discarded) were
 classified as bycatch. Sciaenids, crabs, shrimp,
 clupeids, Bombay duck, mollucsc, and elasmo
branchs made up the bulk of the catch. The only
 species identified throughout the study period was
 Coilia dussumieri, but Harpadon nehereus was the most
 prevalent species that contributed to the weight as
 a single species. Gobies, angler fish, puffer fish,
 tripod fish, some crab species, stomatopods, octopus, gastropods, bivalves, and juveniles of high
 commercial value fishes were among the species
 that were discarded. Target catch, retained bycatch
 and discards constituted 9.4%, 54.8%, and 35.8%
 respectively of the overall catch. Use of bycatch
 reduction strategies, nets with better selectivity and
 seasonal ban on trawling is suggested for sustaining
 trawl fisheries along the coast.