Best estimates indicate that an average of about two deaths or serious injuries per year result from collisions with ships, and since 1991, about one-half of all recorded right whale deaths have been attributed to ship strikes. This may represent only a fraction of the total number of whales killed by ships, as many deaths may go undetected if whales drift out to sea. Although other large whale species may also be hit by ships, the behavior of right whales makes them particularly vulnerable to ship strikes. Right whales occur close to shore, and in areas in or adjacent to major shipping lanes. Their feeding and calving areas, and migratory corridors are crossed by international shipping routes.
Right whales spend much of their time at the surface, feeding, resting, mating, and nursing.
Calves are particularly vulnerable, because they spend a most of their time at the surface because of their undeveloped diving capabilities. Right whales appear to be unaware of approaching ships and apparently make little effort to avoid them. Thus, mariners cannot assume that whales will move out of their path. Mariners may have difficulty in seeing right whales because of their dark color and low profile in the water. Much of the program is aimed at increasing mariner's awareness of the severity of the problem and seeking their input and assistance in minimizing the threat of ship strikes.