Whale and dolphin collisions with ships and pleasure craft are a potentially significant cause of mortality. The seas are busier now than ever before, and the size and speed of commercial shipping is increasing. Cetaceans, and other marinelife are not evolved to be able to adapt to these changes. The scale of the problem is very hard to assess as most large ship collisions go unreported and often unnoticed.
Where shipping is concentrated on busy routes that pass through important marine mammal habitat it is inevitable that the risk of collision increases. In the case of rare species any deaths through collision are highly significant, and when the species range is restricted to areas with high shipping traffic, eg in the case of the North Atlantic Right Whale with a global population of less than 400 animals, the problem could be critical. More than 50% of the known deaths of North Atlantic Right Whales between 1970 and 2006 involved shipping collisions. The small isolated Fin Whale population in the north western Mediterranean is also vulnerable.
Concern has been expressed by ASCOBANS about the proliferation of high speed ferries (traveling in excess of 30 knots) and the risk of collision with small as well as larger cetaceans in the English Channel in particular, but also in other high traffic areas. Fast ferries have limited maneuverability and the mammals have less time to react to their presence hence collision risk is increased.
Small pleasure craft abound in coastal waters, and collisions are inevitable. Inshore dolphins often show injuries from high speed small propellers. The numbers of fatalities are impossible to quantify. There are even several documented cases of whale watching vessels fatally injuring whales! Species include Minke, Fin and Humpback Whales.
 ASCOBANS the Agreement on Small Cetaceans of the Baltic and North Sea. An agreement between governments on the conservation of small cetaceans, in an area that is now extended to include western European Atlantic http://www.ascobans.org/index0101.html