Dalls Porpoise

Common Name: Dall's Porpoise

Class: Mammalia

Order: Cetacea

Suborder: Odontoceti

Family: Phocoenidae

Genus: Phocoenoides

Species: Phocoenoides dalli

 

Taxonomy/Description

Dall's 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.

Habitat/Diet

Dall's 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 northwest.

Behavior/Reproduction

Dall's 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 and whales.

Dall's 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.

Conservation

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.


 

Content provided by Canisius College students under the direction of Michael Noonan, PhD.