Harbour porpoise

 

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Classification:

Population mondiale

Description Et Histoire Naturelle

Physical Description
Harbor porpoises are one of the world's smallest cetaceans (whales). They have a small, robust body measuring an average of 1.55 meters (5.1 feet) and weighing about 55 kilograms (121 pounds). Females are usually larger than males, although this is not readily apparent in the wild.

These small whales are gray to black on the back, and white or light gray on the belly. The snout is blunt and the dorsal fin small and triangular.

Natural History
Harbor porpoises inhabit temperate waters of the North Pacific and North Atlantic oceans and the Black Sea. They are usually found in coastal waters of less than 150 meters (492 feet). Their common name is derived from their appearance in bays and harbors.

Harbor porpoises travel alone or in small groups. They are shy and will avoid boats underway. Harbor porpoises reach sexual maturity at three to five years of age. Females give birth to one calf per year after a gestation period of ten to eleven months. Calves measure 67 - 85 centimeters (26 - 34 inches) at birth and weigh about five kilograms (11 pounds).

The harbor porpoise diet varies with season and prey distribution but is known to include herring, capelin, gadoid fishes such as pollack and hake, and sometimes squid. Harbor porpoises usually live to be about 12 years old.

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Situation De L'Espèce

Status
The harbor porpoise was listed as Threatened by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC) in 1991. The Northwest Atlantic harbor porpoise is designated as a Strategic Stock under the US Marine Mammal Protection Act (MMPA). The IUCN lists harbor porpoises globally as Vulnerable.

Threats to the Species
Harbor porpoise populations around the world have been depleted by fisheries bycatch. They may also be at risk from chemical and noise pollution. In areas where aquaculture is present, habitat degradation may be a factor. The use of acoustic harassment devices in those areas may also be excluding harbor porpoises from certain areas.

International Trade
None.

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Auteur Et Sources

Sources
COSEWIC. 2001. http://www.cosewic.gc.ca

Environment Canada. 1999. http://www.speciesatrisk.gc.ca

International Marine Mammal Association. 2001. http://@phocoena.org.

IUCN. 2001. The 2000 IUCN Red List of Threatened Species. http://www.redlist.org

WDCS. 2001. http://www.wdcs.org

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