Whale species > Dalls porpoise
Dall's porpoises are mainly black with a striking white patch on their bellies and flanks, making them easy to identify. They mature to around 2m in length and have 19 to 23 spade-shaped teeth. They have a small triangular dorsal fin and the back edge of their tail flukes has a greyish-white band. When swimming, Dall's porpoises leave a characteristic splash called a 'rooster tail.'
Dall's porpoises live only in the North Pacific Ocean. Although population numbers are unknown, They appear abundant throughout their range.
Dall's porpoises are thought to have a varied diet consisting of squid, anchovy, sardines and other small schooling fish. Captive Dall's porpoises emit low frequency clicks that, as with other toothed whales, are probably used for echolocation and hunting.
Female Dall's porpoises mature at six, while male Dall's porpoises mature at eight. Females typically have calves every three years. Dall's porpoise calves are about 0.9 metres long when they are born after a 12-month gestation period. Calves and their mothers live separately from the main porpoise herds for a time. They usually live until they are between 16 and 17-years-old.
Researchers believe that Dall's porpoises are susceptible to by-catch in commercial fishing. They become so intent on the pursuit of their food that they fail to see gill nets set for fish, become entangled and drown.
The Japanese also catch a sizeable proportion of Dall's porpoises. This has increased since the International Whaling Commission (IWC) moratorium on large whales. Conservationists believe that the scale of the Japanese hunt is large enough to threaten the species. It is the largest hunt of any whale, dolphin or porpoise species in the world, with more than 18,000 animals killed each year in Japanese coastal waters. In July 2001, the IWC passed a resolution calling for a stop to hunting until a population estimate had been conducted. Japan refused to comply, stating that the IWC writ only concerns large whales, and that in attempting to deal with the small cetaceans it had overstepped its boundaries.