GUWS Medical

Hookers sea lion

Phocarctos hookeri

SUBFAMILY

Otariinae

TAXONOMY

Phocarctos hookeri (Gray, 1844), "Falkland Islands and Cape Horn" (in error, actually "Auckland Islands").

OTHER COMMON NAMES

English: Auckland sea lion, New Zealand sea lion; French: Lion de mer de Nouvelle-Zélande; German: NeuseelandSeelowe; Spanish: Léon marine de Nuevo Zelandia.

PHYSICAL CHARACTERISTICS

Males to 992 lb (450 kg), nearly black; females to 364 lb (165 kg), light tan in color. Pups of various colors with a light stripe down the nose.

DISTRIBUTION

Ocean near Auckland Islands, Campbell Island, and other islands near New Zealand.

HABITAT

The species breeds on protected beaches on three islands of the Auckland Island group, Campbell Island. It hauls out on many other islands in the New Zealand area. Animals may breed on sand or under shoreline trees.

H Phocarctos hookeri H Neophoca cinerea i

BEHAVIOR

The species forms relatively small colonies. Males are territorial, and females form a dense aggregation. At Enderby Island the female aggregation moves along the beach parallel to the water line during breeding. Juvenile males intercept females departing for foraging, and may mate. After the breeding season females move inland to suckle their young in the forest.

FEEDING ECOLOGY AND DIET

The species is reported to take 33 species of prey (fish 59% of diet, cephalopods 22%, crustaceans 15%). Females are largely bottom feeders, dive night and day continuously while at sea, and reach maximum depths of 1,312 ft (400 m). Males occasional take penguins, and cannibalism has been reported. Females often regurgitate rocks and octopus beaks.

REPRODUCTIVE BIOLOGY

Polygynous. The females wean their young by one year of age. No major deviations from typical reproductive biology are known.

CONSERVATION STATUS

Listed as Vulnerable. Hooker's sea lions were formerly more abundant and widespread before being reduced by commercial and subsistence (Maori) sealing. The present population is estimated at 13,000. Its numbers have been stable for 20 years.

SIGNIFICANCE TO HUMANS

Bycatch in a squid fishery on the Auckland shelf may threaten this species. ♦

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