Trawling and by-catch: Implications on marine ecosystem

Trawling remains a controversial method of fishing due to the perceived lack of selectivity of the trawl net and the resultant capture of a huge quantity and diversity of non-target species, including endangered species such as sea turtles, coupled with its effect on the marine ecosystem. The impacts of trawling on the physical, chemical and biological environment of the marine ecosystem and the diversity and quantity of by-catch and discards remain poorly documented for the tropical waters. In India, the by-catch landed at fishing harbours are utilized mainly for the production of manure and animal feed. Further, by-catch reduction devices have not been implemented in the field. This review article, besides analysing the impact of trawling, highlights the need for adopting policies and practices that reduce the level of by-catch, the need for ecosystem-based management to ensure longterm sustainability of oceanic resources, and the adoption of a precautionary approach with emphasis on reducing, and if possible avoiding discards.