Northern fur seal  (Callorhinus ursinus)

The fur that protects the northern fur seal from the cold has led to the animals being hunted for centuries. Although early native peoples made little impact on their numbers, the ‘discovery' of the species in the 18th century was followed by commercial hunting that nearly led to the seals' extinction by the end of the 19th century. In 1911 a treaty, the North Pacific Fur Seal Convention was signed by the USA, Japan, Russia and the UK (acting for the Dominion of Canada), limiting hunting to immature males on land and banning all sea hunts (4).

Although serious commercial hunting of the northern fur seal has ended, the animals no longer enjoy the protection of the international treaty which lapsed in 1984. Neither is the animal currently protected under CITES (Convention on International Trade in Endangered Species) (5).

There is still some hunting permitted under licence in Canadian waters by native peoples only (5), and a similar agreement exists for natives of the Aleutian Islands (4). But the main threats globally are now believed to be caused by entanglement in the nets of the Japanese squid fishing fleets and in the Bering Sea. Seals are also threatened by marine pollution such as plastic twine and waste packaging, as well as discarded trawl nets. The animals are very vulnerable to oil pollution and, with an increase in oil and gas exploration around several of their breeding grounds, there are fears that accidental oil spills and the inevitable industrial disturbance will affect seal populations (4).

The North Pacific Fur Seal Convention lapsed in 1984 after an extension was vetoed by the USA (5), but all commercial hunting has ceased at sea and only limited numbers are now taken under licence. It is believed the world population currently stands at about 1,350,000 animals, but with no current international agreement, some experts fear that commercial hunting could start again at some time in the future. There is also evidence that the El Niño event of 1997-8 affected the pup survival rate of the San Miguel Island breeding colony. A drop in the availability of fish led to 87% of young fur seals dying before they were weaned (4).