Dolphins and all toothed whales, besides the sperm whale, are covered by ASCOBANS. They cross international borders and depend therefore on transboundary protection measures. ASCOBANS was opened for signature at the United Nations Headquarters in New York on 17 March 1992. So far, ten European countries have joined the agreement, including Germany. In 2008, the Agreement area, which originally comprised only the North Sea and the Baltic Sea, was extended to include the North East Atlantic and the Irish Sea.
Numerous dangers threaten individual animals and even entire populations of marine mammals. Bycatch, the accidental capture in fishing nets, in which animals are entangled and suffocate, ranks first. As a result, thousands end up in fishing nets every year. In the long term, ASCOBANS aims to reduce the mortality rate to zero.