Demonstration of off-bottom trawl systems (OBTS) in coastal waters of Goa, India as an ecofriendly trawl design

Abstract

Marine capture fisheries contributes significantly to the economy of Goa. Though bottom trawling is a widely practiced fishing method, it often affects the benthic ecosystem adversely. In this context, offbottom trawl system (OBTS), an ecofriendly trawl design compared developed by CIFT was demonstrated in Goa. The operational efficiency of a 22 m high density polyethylene (HDPE) OBTS fitted with 65 kg suberkrub otter boards was tested on-board mechanized trawlers along the coastal waters off Chapora, Goa. Five hauls of one hour duration each were carried out at 10 to 12 m depth zone. A total of 43 different species of finfish and shellfish were present in the catch. The absence of bottom dwelling organisms like shrimp, squilla and gastropods which are generally encountered in bottom trawls was conspicuous in OBTS. The off-bottom fishes contributed 83% and pelagic fishes contributed 17% of the total catch in the OBTS. The CPUE for the 22 m OBTS was 15.5 plus or minus 6.9 kilpgram per hour. The top five species caught in the OBTS were Alepes kleinii (31.11%), followed by Alepes djedaba (15.6%), Atule mate (12.07%), Otolithes ruber (4.32%) and Megalaspys cordyla (3.04%). The results of this study show OBTS as a potential gear which can replace the deleterious bottom trawls in non-shrimp seasons for capture of off-bottom species with minimum impact to the benthic ecosystem.