The New Zealand sea lion (Phocarctos hookeri) is also known as Hooker’s sea lion, and to Māori as whakahao. Its main food is fish and cephalopods such as squid and octopus.
The males are much larger than fur seals and have a distinctive blunt nose. Dark brown, with a mane of thick hair about the neck and shoulders, they can tip the scales at over 400 kilograms. Females weigh about half that, and are creamy yellow.
The main breeding grounds are in the Auckland Islands. A small number breed on Campbell Island, the Snares Islands and in isolated cases on the Otago coastline.
The sea lions like sandy beaches, of which there are plenty, but 95% of the population breeds on three beaches in the Auckland Islands. Such a concentration makes them vulnerable: in 1998 a mystery illness killed over half that year’s pups and perhaps 20% of the adults. A squid fishery, which started around the islands in the 1980s, has killed thousands of them in trawl nets.
They are the world’s most threatened sea lion species, with about 12,000 individuals remaining in 2022. The number of pups born in the Auckland Islands halved during the 2010s.
Little is known of where they used to breed. The sites were probably more widespread until the early 19th century when sealers, faced with dwindling catches of fur seals, began exploiting them. While sea lions have long hauled out (rested) along the Otago–Southland coastline, it is encouraging that females have also begun pupping on the Otago Peninsula and in the Catlins, on the South Otago coast.
When not breeding, sea lions can be found scattered around the coasts of the islands where they breed, but at any time a large part of the population will be away at sea.
The breeding pattern of sea lions is very similar to that of fur seals, with males arriving in November to set up territories. Pregnant females arrive a month later, and mate 7–10 days after giving birth. Pups may be weaned anywhere from nine months to over a year. Females start mating at four years, and males later.
The maximum recorded age is 23 years for males and 18 for females.