The biggest killer of cetaceans is the fishing net. This is a problem that occurs in EVERY ocean. thousands of dolphins die in nets each year and hundreds of dolphins wash up on shore in the North East Atlantic, mostly the coasts of France and the UK. Pelagic (mid-water) trawl fisheries and gill and tangle nets that lay on the ocean floor are drastically reducing dolphin and porpoise populations.
The common dolphin has become a major bycatch of the winter sea bass fisheries in the UK.
The right whales' feeding grounds in the northeast coast of the US overlap with several fisheries. As a result, the whales become lethally entangled in gillnets and lobster and crab gear. Some whales will carry the razor-thin nets embedded in their skin or bones for years, slowly suffering agonizing deaths, as the net inhibits their ability to swim and feed properly.
Harbour porpoises, a species facing extinction, face a dramatic decline in the Baltic sea as a result of fishing nets and bycatch.
Spotted and Spinner dolphins are constantly entrapped in nets because of their close association with yellowfin tuna. They are traumatized, injured, and killed.
Drift nets (nets that reach mile long lenths, are many feet deep, and are left unattended for weekd) have been outlawed internationally due to the high numbers of mammals, birds, turtles, and sharks killed.
