Common Name: Dall's Porpoise
porpoise belongs to the Mammalian Order Cetacea, in the suborder
Odontoceti. All toothed whales belong to the suborder Odontoceti,
which is Latin for "toothed whales". Dall's porpoise belongs to the
porpoise family, Phocoenidae. Other members of this family include
the harbor porpoise and finless porpoise. The Dall's porpoise's
scientific name is Phocoenoides dalli, which means "Dall's
porpoise". It is named for William H. Dall (1845-1927), an American
naturalist working with the U.S. Geographical Survey from 1884 to
1909. Dall captured the first specimen. Dall's porpoises are black
with large white dorsal patches. Both males and females grow to
about lengths of 6-7ft and weigh about 270lbs.
porpoises live throughout the North Pacific, along the North
American coasts of California, Canada, and Alaska, and the Asian
coasts of Japan, Korea, and Russia. Cooler, open waters are
preferred by this species. Small school fish species, like herring,
capelin, and sardines are a primary food source. Deep sea smelt,
hake, and squid are also preyed upon. Lantern fish are
predominantly eaten by Dall's porpoises living in the Pacific
porpoise is arguably the fastest small cetacean. They may attain
speeds up to 30 knots. Such a speed is possible due to the
porpoise's ability to breath without breaking the water's surface.
A bow wave, called a "rooster tail", is caused by its head and
tail. This wave is a hollow cone of water, allowing the animal to
breathe. They are often observed bow riding on fast moving boats
porpoise calves are 3.5 feet long at birth. Males reach sexual
maturity at eight years, with females maturing sexually at seven
years. Groups of 10-20 animals are common, although larger groups
often form near common food resources. Migration is uncommon. Most
Dall's porpoises reside in their home range year round.
Although currently numerous, Dall's porpoises are in need of further
protection. Fishing nets from high seas Japanese fishing operations
accidentally entangle thousands of Dall's porpoises each year.
Japaneses whaling operations also harpoon this species for food.
Over 39,000 animals were harpooned in 1988 alone. Without ample
protection, this species numbers will continue to decline.