First Mainland New Zealand Sea Lion Breeding Colony in over 150 Years

New Zealand sea lion (Phocarctos hookeri)

Seal hunting in New Zealand has a long history, as old as human habitation in the country.  New Zealand fur seal/kekeno (Arctocephalus forsteri) and New Zealand sea lion/rapoka (Phocarctos hookeri) colonies were found commonly throughout New Zealand's mainland coastlines before the arrival of Maori.  New Zealand sea lions appear to have been exterminated from the North Island entirely by 1500 AD and New Zealand fur seals were missing from at least the northern half of the North Island by this time as well.  When Europeans arrived New Zealand fur seals had been eliminated from all of the mainland except for the south-western South Island and New Zealand sea lions could no longer be found on the South Island except in the regions around Stewart Island.

Sealing was the first European industry in New Zealand and began in 1792.  European sealing was driven by the demand for their hides and oil in Europe and North America.  Harvesting was intense, with sealers often returning with 10,000-60,000 seal skins per ship.  By the 1830's sealing as an industry nearly ended in New Zealand since seals had become too rare and it was nearly impossible to find enough to be financially lucrative on a large scale any more.  Sealing continued until 1946 but was regulated more and more over time with required hunting permits and more frequent closed seasons.  Since then, populations have not been hunted but will likely never recover to their pre-human numbers and range.

The good news is that for the first time in more than 150 years the New Zealand sea lion has established a breeding colony on New Zealand's mainland, on Stewart Island/Rakiura.  The new colony had 55 pups born this year and numbers of animals have been consistent at the colony for several years now, leading DOC to officially declare it a breeding colony.  This is excellent news for the species, whose population currently numbers only around 12,000 individuals.  Prior to this new colony, all of the breeding colonies had been found on the safer offshore islands of Campbell Island/Motu Ihupuku and the Auckland Islands in the subantarctic for this Nationally Critical (New Zealand's highest threat classification) endemic, although a very small number of sea lion births have recently started happened away from the two main colonies, on Stewart Island and the southern South Island.  It is also wonderful news for Kiwis hoping to catch a glimpse of a New Zealand sea lion.  Although male sea lions/whakahao-rapoka will often roam widely outside of the breeding season, females/kake and pups typically stay relatively near to the breeding colony throughout the year.  More breeding colonies on the main islands means that sightings of New Zealand sea lions will be a much more common occurrence for all of us.  Unfortunately, the future continues to look poor for the New Zealand sea lion, even with the founding of this new breeding colony.  Their numbers continue to decline but scientists are not entirely sure what is causing the declines.  Fishing related deaths, climate and/or nutritional stresses, human attacks, high pup mortality, and disease (in particular Klebsiella pneumoniae) issues are causes but it is difficult to tease out the main causes behind the decline.  While management measures have been put in place within the fisheries industries intended to greatly reduce sea lion mortality, numbers of New Zealand sea lions sadly continue to decline by ~4% each year.  The New Zealand sea lion can use all the help it can get, but it is delightful to see it begin to make a meaningful comeback on the mainland.  Fortunately, New Zealand's Department of Conservation has some of the best conservation biologists in the world on their staff, and New Zealanders as a whole are driven to protect the remaining natural heritage, so if anyone can save the New Zealand sea lion from extinction, it is New Zealand's conservation community.  They continue to conduct research to determine the main causes of decline of the species and how to mitigate them.

Here are the references that I used, and I highly recommend checking them out if you are looking for more information about New Zealand sea lions:

S. Childerhouse & N. Gales (1998) Historical and modern distribution and abundance of the New Zealand sea lion Phocarctos hookeri. New Zealand Journal of Zoology, (25); 1-16.  http://doi.org/10.1080/03014223.1998.9518131

Department of Conservation. (10 April 2018). First new NZ sea lion breeding colony in more than 150 years. Retrieved from http://www.doc.govt.nz/news/media-releases/2018/first-new-nz-sea-lion-breeding-colony-in-more-than-150-years/

Department of Conservation and Ministry for Primary Industries. (2017). New Zealand sea lion/rapoka threat management plan.

IUCN. (2017). The IUCN Red List of Endangered Species: Phocarctos hookeri. Retrieved from http://www.iucnredlist.org/details/full/17026/0

C. Lalas & C.J.A. Bradshaw (2001) Folklore and chimerical numbers: Review of a millennium of interaction between fur seals and humans in the New Zealand region. New Zealand Journal of Marine and Freshwater Research, 35(3); 477-497. http://doi.org/10.1080/00288330.2001.9517017

I.W.G. Smith (1989) Maori impact on the marine megafauna:Pre-European distributions of New Zealand sea mammals. Pp. 76-108 in Saying so doesn’t make it so ed by D.G. Sutton. New Zealand Archeological Association: Auckland.

I.W.G. Smith (2011) Pre-European Maori exploitation of marine resources in two New Zealand case study areas: species range and temporal change. Journal of the Royal Society of New Zealand, (43); 1-37. http://doi.org/10.1080/03036758.2011.574709