It claims as many as 20,000 porpoises could have died off the United Kingdom's coasts in the last six years. The harbour porpoise is the UK's smallest cetecean, a collective term for whales, dolphins and porpoises.
Harbour porpoises are smaller than their dolphin cousins and feed on small fish near the sea floor.
This feeding habit brings them into contact with bottom set gill nets - fishing nets set on the seabed. As mammals needing to breathe oxygen, porpoises can struggle for up to four minutes entangled in these bottom set gill nets, suffering cuts and bruises as the nets slice into their skin. Some suffer broken teeth and jaws before they run out of oxygen and die. Although the government has commissioned research into the problem it has failed to introduce the changes in fishing practices which are sorely needed. At those levels the slow breeding harbour porpoises could disappear from the area by the end of the century.