Arctocephalus forsteri
New Zealand fur seal

Arctocephalus forsteri is found throughout New Zealand and in western and southern Australia (Department of Conservation).

New Zealand fur seals oscillate between aquatic and terrestrial habitats. When in the ocean, they are observed both far and near from shore. During the breeding season, however, fur seals spend most of their time along a rocky coastline, especially preferring those areas with an abundance of large boulders, crevices and caves so as to shelter and provide protection for pups. Further, Arctocephalus forsteri prefers areas which are near sheltered water or intertidal pools (Seal Conservation Society).

Extreme sexual dimorphism characterizes this species: while the average female weighs approximately 40kg and is 1.2m in length, the average male weighs close to 160kg. and is 1.6m in length. New Zealand fur seals have sharp, elongate snouts and external, visible ears. They are covered by two layers of fur which is actually dark brown, but when wet Arctocephalus forsteri may appear black (Department of Conservation).

Male fur seals attain and defend territories once they reach approximately 8-10 years of age. Breeding males come to shore in early November to compete for and establish territories, which eventually may support up to 16 females. Adult females begin arriving in mid-November to choose males. In Dec/Jan. females give birth to those pups conceived during the last breeding season. Once the young reaches 6-12 days old, the mother begins going to sea to feed. Females alternate between offshore foraging and onshore nursing and caregiving. Foraging trips become longer as the pup gets older. Females and pups can be found at the rookery throughout the year. Adult males remain onshore for the entirety of the breeding season, often not feeding for up to 2 months. They return to the sea by mid-January.

Much work has been conducted in studying diving behavior. It has been observed that lactating females are constrained to areas near the breeding site. Further, it has been shown that most dive depths ranged from 12-18m, and the maximum depth observed was nearly 163m. Durations of dives were from 3.2 to 6.2 min, but the average dive length was much shorter (0.7-1.2min). Dives tended to occur nocturnally, and dive depth varied with time of night, with deepest dives being near dusk and dawn (perhaps because prey was just starting to either rise from extremely deep depths, or was beginning to fall back to deep depths after feeding). Duration of the dive was found to be correlated with the depth (deeper dives required more time). (Harcourt, et al., 1995).

Arctocephalus forsteri primarily feeds on aquatic species such as arrow squid, octopus, barracuda and jade mackerel. The seals are found to feed beyond the continental shelf in depths greater than 22m. Because its prey includes many vertical migrators (those organisms that rise to the surface during the night to feed and sink during the day), fur seals are found to feed almost exclusively during the night. These seals have been observed feeding continuously from sundown to dawn (Department of Conservation).

Often fur seals interfere with commercial fishing equipment by becoming tangled in nets. In these instances they are usually killed. Further, many fishermen intentionally try to capture and kill them due to the belief that the seals deplete commercial fish stocks. It has been shown that fur seals eat minuscule amounts of commercially important fish and instead the bulk of their diet consists of organisms not used by humans. Unfortunatley, however, the practice of killing them continues (Forest and Bird Society).

In the 18th and 19th centuries, Arctocephalus was widely hunted for food by the Maori people. With the onset of European sealing industry, fur seals were hunted for their fur in addition to their meat. Starting in 1894, however, both of these activities were deemed illegal and the New Zealand fur seal was granted full protection (Department of Conservation).

Although presently it is not legal to hunt Arctocephalus forsteri for fur or meat, they are still extremely threatened by human populations. They are subject to pollution, which affects their health in addition to actually physically trapping and drowning them. New Zealand fur seals are also inadvertantly caught in hoki nets that are set for other aquatic species. There have been observed increases in their population, however, in recently years at rates near 16-19%, and their numbers are quoted at being near 60,000. Fortunately, the future of Arctocephalus forsteri looks promising despite pollution and accidental catching (Forest and Bird Society).