Sea snakes are a species-rich (~70 species) group of marine reptiles found throughout the tropics (excluding the Atlantic). They consist of two distinct groups, sea kraits (Laticauda) and true sea snakes (Hydrophiinae). Hydrophiids are highly adapted to a life permanently at sea and are also highly venomous. These animals are frequently caught in fishing nets as bycatch, especially in trawlers. These encounters can be deadly for the snake and sometimes for the fisherman. Sea snake populations are highly localised and take a long time to recover. There is limited knowledge about sea snakes in India. Apart from a few studies in Goa, Kerala and Tamil Nadu, information on sea snake assemblages and their response to fishing pressure is lacking. Our study is looking at the effects of fishing practices on sea snake populations and their ecology in the Sindhudurg district of Maharashtra.
Following are some findings from our previous study (2016 – 2017):
- We encountered 3 species – the hook-nosed sea snake (Hydrophis schistosus), the spine-bellied sea snake (Hydrophis curtus) and the little file snake (Acrochordus granulatus).
- The hook-nosed sea snake was encountered the most often, in all types of fishing nets. We encountered very few individuals of the spine-bellied sea snake, although they predominated catches over a decade ago.
- The spine-bellied sea snake had a higher mortality rate than the hook-nosed sea snake. Both species had a higher mortality rate in trawl nets than in gill nets.
- We encountered 5 dead gravid females of the hook-nosed sea snake. Gravid females appeared to be very vulnerable to trawl fishing.
Our current work focuses on the following objectives:
- To characterise the species composition, biomass and spatio-temporal patterns of fisheries bycatch.
- To determine the impact of fishing practices on spatial (habitat and movement), feeding and population ecology of sea snakes.