Hooker’s Sea Lion

(Phocarctos hookeri) at Waipapa Point
Hooker’s, or New Zealand, sea lion only breeds around the New Zealand sub-Antarctic Islands. The population was estimated at around 11,000 to 15,000 animals, prior to the mass die-off in 1998. Of these, 95 percent breed on two small islands off the Auckland Islands – Enderby and Dundas Islands. Dundas Island, where 75 percent of the animals breed, is only the size of two football fields. A small population lives around Campbell Island and occasional vagrant pupping occurs on Snares Islands and on the Otago Coast.

The seal specialist group of the Species Survival Commission (a group of 7000 international specialists) of IUCN (the World Conservation Union), ranks Hooker’s sea lion as a vulnerable threatened species.

The Minister of Conservation has gazetted Hooker’s sea lion as a threatened species under the Marine Mammals Protection Act. This was opposed by the fishing industry.

Population Problems
Each year dozens of sea lions die a painful, terror-filled death in the gigantic trawl nets of the Auckland Islands squid fishery. These sub-Antarctic Islands are the birth place of ninety five percent of the world’s New Zealand sea lion pups. Since the squid fishing season coincides with the sea lions‘ breeding season, many of the victims are pregnant and nursing mothers whose unborn pups die with them, and whose pups on shore starve to death.

The population may have been reduced by over 20% in the 1998 disease event. The actual extent of mortality of adults may never be known but over 50 percent of the pups died. In 2002 the reduction in the number of pups born, by around 20 percent, and deaths of up to 25 percent of pups further threatens the sea lion.

Approximately 95% of the sea lion population (estimated at little more than 11,000) breed on two very small islands off the Auckland Islands. Since trawl fishing for squid commenced in the Auckland Islands in the early 1980s, over 2000 New Zealand sea lions have drowned in trawl nets.

Though sea lion deaths were recorded in the first experimental squid trawls undertaken near the Auckland Islands in 1978, sea lions are still referred to as an „accidental bycatch“ of the squid fishery. In fact, sea lion deaths are an inevitable consequence of trawling near the Auckland Islands.

An Historical Perspective
Early nineteenth-century sealers hunted populations of sea lions to near extinction. In 1830 Benjamin Morrell, skipper of the schooner Antarctic, recorded in his journal that;
„Although the Auckland Isles once abounded with numerous herds of fur and hair-seal [the old name for sea lions], the American and English seamen engaged in this business have made such clean work of it as to scarcely leave a breed.“

Sea lions were later eaten by sailors who were frequently shipwrecked on the Auckland Islands. When the schooner Grafton was wrecked there in 1864 the crew subsisted on sea lion meat, and the captain Thomas Musgrave wrote his journals using sea lion blood for ink.

Hooker’s sea lions were killed for pelts by sealers in the early 1800s and reduced to very low levels. It is likely that the population has not yet recovered to pre-European levels. Evidence indicates that Sea lions bred in Northland, the Nelson area and on the Chatham Islands in the last 1000 years but were eliminated by Maori harvests.