Bycatch and discards in gillnets operated along Tharuvaikulam fishing village, south east coast of Tamil Nadu

Abstract

Gillnet fishing is a very popular fishing method owing to its simplicity in design, ease of handling, less fuel consumption and low cost. The Tharuvaikulam fishing village by its switch over of fishing method from trawling to gillnetting is unique from other fishing villages of Tamil Nadu coast. A study was conducted along Tharuvaikulam coast on the catch composition and quantification of bycatch and discards of different types of gillnets operating in this area during June 2015 to July 2016. There were seven types of gillnets based on the targeted fishery and they are categorized according to the depth of operation. They are, large mesh drift gillnet (paru valai), full beak net (mural valai), half beak net (katta mural valai), flyingfish net (parava valai) are drift nets, crab net (nandu valai), ray net (thirukkai valai) and cephalopod net (kanava valai) are bottom set nets, and cephalopod net is a trammel net. The study revealed that 94 to 99% of catch in drift gillnet operated along the coast composed of targeted species while bycatch and discards was very insignificant. Among the different gillnets, flying fish net was the best in catching targeted fishery without any discard. Whereas, catch composition of bottom set gillnet revealed considerable amount of bycatch and discards. Mean quantity of target catch, bycatch and discard in different bottom set gillnets were 44.9, 32.0 and 23.1 per cent in crab net; 67.4, 4.1 and 28.5 per cent in ray net; 13.5, 58.6 and in ray net; 13.5, 58.6 per cent in cephalopod net respectively. Cephalopod nets had the maximum bycatch while ray gillnets had the maximum discards. Among the gillnets operated along Tharuvaikulam coast, drift gillnets were better than bottom set gillnets and trammel nets in harvesting the target catch with less bycatch and discards.