The number of cetacean-vessel collisions, worldwide, has dramatically increased and has become more evident in the past 50 years. Endangered, endemic, and geographically isolated cetacean populations are involved in the collisions, creating a significant threat to the recovery and survival of their populations. In certiain areas, up to 1/3 of whales of certain populations found dead show signs of dying because of a vessel strike.
North Atlantic Right Whales survive in a population of less than 400 whales. More than 10/18 of post-mortem findings between 1970 and 2002 indicated that vessel collisions were a major contributing cause of death.
Not all collisions result in immediate death. Sometimes the injured cetacean will die years later. Numerous sightings of whales and dolphins wiht flukes, deformed dorsal fins, and wounds point to propeller strike suggestions.
One known case of survival after collisions, a pregnant North Atlantis Right Whale was believed to have died as a result of infections from a ship strike wound that she had received as a calf ('Right Whale News' May 2005)
The problem has intensified due to the obvious increase in the number of vessels, their speed, and size. Right Whales, for instance, are attracted to a planktonic copepod which are believed to be dependent on salinity and temperature. This lures the whales into the Gulf of Maine, resulting in collisions.
Most recorded collisions that result in mortalities occur when vessels are traveling in an excess of 13 knots. When collisions occur at lower speeds, the damage to the cetaceans and the vessel are much less serious.
The total number cannot be accurately estimated because not all collisions are reported, the remote location, or the inability to retrieve the carcass for necropsy. What is known, is that this is another extremely threatening and common danger to all cetaceans.
