Finfish constituents of trawl low value by-catch off Mangalore

Abstract

Trawling remains a controversial method of fishing due to the poor selectivity of trawl net and catching of hugequantity and diversity of non target fishes. By-catch is recognised as an unavoidable portion of fish catch but quantity variesaccording to the type of gear operated. FAO has considered the resource damage due to discarding of by-catch as serious issue.Mangalore fisheries harbour is one among the major fishing harbours of Karnataka state with its significant contribution tothe Trawl landings. The study was conducted to assess the recourse damage due to indiscriminate fishing and landing of juveniles of commercially important species in low value by-catch due to smaller size and improper handling. The quantity of lowvalue by-catch was estimated from the landings of single-day and multi-day trawler landings for the period of August 2012 toMay 2013. The quantity of low value by-catch (trash fish) generated by trawlers of Mangalore was estimated as 32,426 t (19%of the total trawl catch). A total 121 species of finfishes belonging to 55 families have been identified constituting the low valueby-catch. Order Perciformes contributed 61.16 per cent (74 species) to the total number of species, followed by Clupeiformesand other groups, whereas the family Carangidae contributed 11.57 per cent (14 species) to the total number of species, followedby Engraulidae and other families. Presence of wide diversity of finfishes in low value by-catch showed an alarming signal of fisheries resource damage.