By-Catch

By-catch is the greatest threat to the survival of dolphins. Over 350,000 dolphins die every year from the incidental capture due to the accidental entanglement in fishing gear, and this number is projected to rise. By getting entwined in the ropes or nets of commercial fisheries, dolphins either suffer fatal injuries, or drown, or starve to death.

Most of the by-catch occurs in gillnets fisheries, usually set out into the sea to target specific groups of fish. Gillnets are mesh nets designed for the gills of fish to get caught when they swim into it, preventing their escape. Gillnets are set up by getting weighed down to the bottom of the sea floor and held up by floats; hence creating a wall of net. Unable to detect them, dolphins often swim right into these nets and hence get stuck, or get tangled in the ropes holding the netting.

While gillnets are the current main concern, other types of fishing gear such as drift nets and trawlers pose problems as well. Drift nets are extended versions of gillnets, indiscriminately killing millions of marine animals, including dolphins. Trawling is a method known more simply as “aimless fishing”, whereby a trawler drags a cone-shaped net behind a boat to catch schooling fish.