The New Zealand sea lion (Phocarctos hookeri ), once known as Hooker's sea lion, and as pakake or whakahao (male) and kaki (female) in Māori, is a species of sea lion that is endemic to New Zealand and primarily breeds on New Zealand's subantarctic Auckland and Campbell islands, and have in recent years been slowly breeding and recolonising around the coast of New Zealand's South and Stewart islands. The New Zealand sea lion numbers around 12,000 and is one of the world's rarest sea lion species. They are the only species of the genus Phocarctos.
The main breeding populations are at the Auckland and Campbell Islands in the New Zealand subantarctic, where approximately 99% of the species' annual pup production occurs. There are currently three functioning breeding rookeries on the Auckland Islands. Most sea lions are born on Dundas Island. A smaller rookery exists at Sandy Bay on Enderby Island and the smallest rookery is on Figure of Eight Island. An even smaller rookery at South East Point on Auckland Island appears to now have been abandoned. The other major breeding area is the Campbell Islands.
Historically, New Zealand sea lions were distributed all over mainland New Zealand and Stewart Island, but were extirpated from these areas due to human hunting activities. For the first time in over 150 years, sea lions began breeding again on the South Island coast in 1993, on the Otago Peninsula. Other small populations of breeding sea lions have recently begun to establish in various parts of the Stewart Island coastline and have been observed on the Catlins coast south of the Clutha River.
Recent DNA information indicates the New Zealand sea lion is a lineage previously restricted to subantarctic regions. Somewhere between 1300 and 1500 AD, a genetically distinct mainland lineage was wiped out by the first Maori settlers, and the subantarctic lineage has since then gradually filled the ecological niche. It has been inferred from middens and ancient DNA that a third lineage was made extinct at the Chatham Islands due to predation by the Moriori people.
New Zealand sea lions are one of the largest New Zealand animals. Like all otariids, they have marked sexual dimorphism; adult males are 240–350 centimetres (7.9–11.5 ft) long and weigh 320–450 kilograms (710–990 lb), while adult females are 180–200 centimetres (5.9–6.6 ft) long and weigh 90–160 kilograms (200–350 lb). At birth, pups are 70–100 centimetres (2.3–3.3 ft) long and weigh 8–10 kilograms (18–22 lb); the natal pelage is a thick coat of dark brown hair that becomes dark gray with cream markings on the top of the head, nose, tail and at the base of the flippers. Adult females' coats vary from buff to creamy grey with darker pigmentation around the muzzle and the flippers. Adult males are blackish-brown with a well-developed black mane of coarse hair reaching the shoulders. New Zealand sea lions are strongly philopatric.
The New Zealand sea lion's terrestrial behaviour is unique among other pinniped species. In the breeding season, female New Zealand sea lions gradually move inland with their pups to protect them from harassment by males, wind, storms, and potential parasitic infections. They can move up to 2 kilometres (1.2 mi) inland, from sandy beaches to tall grasses, and into forests. They are the only pinniped species known to disperse far inland and have a preference for forests.
Food availability is a well-known, major cause of population change in pinniped species. The Auckland Islands population has displayed numerous indicators of food limitation during the recent decline in breeder numbers, including: poor maternal condition, delayed maturation, years with very low pupping rate, low survival of pups born and long-term shifts in diet composition. Starvation was provisionally identified as cause of mortality for 62% of pups necropsied at Campbell Island in 2015, when 58% of all pups born were estimated to have died in the first month of life.
ions are in turn preyed on by great white sharks, with 27% showing evidence of scarring from near-miss shark attacks in an opportunistic study of adult New Zealand sea lions at Sandy Bay, Enderby Island.
Food availability is a well-known, major cause of population change in pinniped species. The Auckland Islands population has displayed numerous indicators of food limitation during the recent decline in breeder numbers, including: poor maternal condition, delayed maturation, years with very low pupping rate, low survival of pups born and long-term shifts in diet composition. Starvation was provisionally identified as cause of mortality for 62% of pups necropsied at Campbell Island in 2015, when 58% of all pups born were estimated to have died in the first month of life.
The mainland population was estimated to reach 1000 animals by 2044, leading to issues of ‘marine protected areas, local fishing quotas and numbers management’.
New Zealand sea lions are projected to potentially distribute all around mainland New Zealand, but they face potential human conflicts, especially due to their unique inland movement behaviour. New Zealand sea lions have been hit by cars on roads, and deliberately killed, harassed, and clubbed. There have also been incidents of disturbance from domestic dogs. Infrastructure such as roads and fences also pose as barriers to their inland movement. Females and pups on the mainland have also adapted to commercial pine plantations, which are privately-owned lands.
In order ensure the protection of New Zealand sea lions, the Department of Conservation works to engage with local communities and spread awareness on this species' recolonisation and behaviour.
New Zealand sea lions are considered the most threatened sea lion in the world. The species' status is largely driven by the main breeding population at the Auckland Islands, which declined by ~50% between 2000 and 2015. The 2013 sea lion pup production count on the Auckland Islands showed the number of pups born on the islands has risen to 1931, from the 2012 figure of 1684 (dead pups are also counted, since the annual pup count is used to assess the population of breeding females, but not future births when the counted pups mature). The 2013 number was the highest in five years. The Campbell Island population 'appears to be increasing slowly' and births here comprise ~30% of the species' total. The Otago and Stewart Island sea lion populations are currently small, though increasing. Population estimates for the whole species declined from ~15,000 in the mid-1990s to 9,000 in 2008 (based on the number of pups born).
In 2010, the Department of Conservation—responsible for marine mammal conservation—changed the New Zealand Threat Classification System ranking from Nationally Endangered to Nationally Critical. The Department of Conservation estimates that Auckland Islands' sea lions, nearly 80% of the total, could be functionally extinct by 2035. However, the New Zealand Ministry for Primary Industries considers research on which this prediction is based is low quality and ‘should not be used in management decisions’. In 2015, the International Union for Conservation of Nature (IUCN) changed the classification of this species to "Endangered", based on low overall population size, the small number of breeding populations and the projected trend of the Auckland Islands breeding population.
In 2019, the New Zealand sea lion's status was found to have improved and they are now "Nationally Vulnerable". Their overall rate of population decline has slowed in most breeding locations and Stewart Island was officially recognised as a new breeding colony in 2018. Their global IUCN status remains "Endangered".
