Threats to Northern Fur Seals

A 2008 survey of the main breeding ground on the Pribilof Islands found the lowest level of northern fur seal pup production since 1916. Climate change may be disrupting patterns of prey abundance in the ocean. As temperatures in the ocean rise, the fish on which northern fur seals depend have begun moving further out to sea, where the water is cooler. If fish numbers are reduced or more plentiful further offshore, seals will need to spend more time foraging, thereby expending more time and energy on feeding and less on reproduction and raising young. This reduces the survival rate of pups, leading to a reduction in the overall fur seal population.

Over-fishing is also depleting fish stocks that the northern fur seals depend on for food, especially after the mothers give birth and need a ready supply of food to keep up their strength while she is nursing her newborns. Fur seals are also continually entangled in squid driftnets used by the Japanese fisheries and Alaskan gillnet and trawler fisheries.

Northern fur seals are very sensitive to warmer waters. Marine mammal rehabilitators report dramatically higher fur seal cases during El Niño years when the water is unusually warm. Fur seals are also susceptible to infection from a hookworm that causes anemia, which can be deadly to pups. Hookworm populations increase when temperature and humidity are higher.

Reasons For Hope

Because of such vigorous hunting of fur seals in the 1800's, in 1911 the North Pacific Fur Seal Convention was founded making it illegal to hunt seals at sea and restricting fur seal hunts to immature male seals on land. Despite the 1911 convention elapsing in 1984, all commercial hunting was stopped of fur seals. However, subsistence hunting by natives is still allowed in some areas.