There are three species of right whales (four if you include the bowhead whale). These are the North Atlantic right whale, the North Pacific right whale, and the Southern right whale. They acquired the name “right” from whalers, because these whales are commonly found near land and because, when killed, the carcasses float. They float because the right whale body has the highest percentage of blubber of any marine mammal – up to 40%. Right whale adults can be up to 60 feet in length and weigh up to 100 tons, making them larger than humpback or gray whales, but smaller than blue whales. Because the two blowholes on the top of the head are widely separated, the right whales can have a V-shaped blow. They lack the dorsal fin common on most whales and have distinctive callosities (roughened patches of skin on their heads), which are home to large colonies of lice. The North Atlantic right whales are the best documented of the species. During most of the year, their live in waters off the coasts of maritime Canada and New England. In the winter months, they live off the coasts of Georgia and Florida, where females give birth to one or occasionally two calves, following a gestation period of one year. Calves typically weigh about one ton and are about 15 feet in length. They are weaned after one year and tend to stay with their mothers for another year. Right whales spend a lot of time on or near the surface and are slow swimmers, never exceeding five knots. This not only made them easy targets for whalers, but now makes them highly vulnerable to modern ships with steel hulls and operating at comparatively high speed. Thus, ship strikes are the leading cause of deaths, particularly among the North Atlantic right whales. The National Oceanic and Atmospheric Administration (NOAA), with the concurrence of the IMO, established a mandatory ship reporting scheme and ship speed limits for certain waters of the western Atlantic Ocean in an effort to reduce such ship strikes. Areas of voluntary speed limits are also announced when right whales are observed in number. Reduction in ship strikes is vital as there are estimated to be only 400 North Atlantic right whales left alive.