New Zealand fur seal

When you think of urban wildlife on the Sunshine Coast, the New Zealand fur seal is probably not the first animal that comes to mind. However, you might be surprised to know that in most years Sunshine Coast beaches are graced with the presence of small numbers of them near local beaches, including in recent years Kings Beach, Pt Cartwright, Pumicestone Passage, and Mooloolaba and Coolum beaches.

More widespread than its common name suggests, the New Zealand fur seal (Arctocephalus forsteri), also breeds in significant numbers along the coast and offshore islands of South Australia, Western Australia, Tasmania and Victoria. Known to be formerly sympatric with the Australian fur seal (Arctocephalus pusillus doriferus) in Bass Strait, populations of both seals were almost decimated through sealing in the late 18th and early 19th centuries. In more recent years, new colonies are establishing in southern Australia and pup production has been increasing at a rate of 21% at some established colonies. By 2007 the total Australian population of A. forsteri was estimated to be around 80,000 with an annual pup production of around 20,000. In the late 1990s, researchers also documented the presence of breeding New Zealand fur seals on some small islands in Bass Strait. If the population continues to grow in that area, the two species may once again co-occur in large numbers in Bass Strait.

But this is all a long way from the Sunshine Coast, so why do we see them on local beaches? While Australian breeding occurs in southern waters, non-breeding seals unbound to a breeding territory frequently occur in smaller numbers off the east coast of New South Wales and Queensland and in the waters around New Caledonia. So, although we don’t see a lot of them, the Sunshine Coast does fall within the species’ natural extended range.

Females usually give birth at around 4 or 5 years of age and come ashore only 1 or 2 days prior to giving birth. Pups are born between late November and early January weighing around 3-4 kg and will double that weight in 60-100 days. Following birth, the female will stay ashore nursing the pup for around 10 days before returning to the sea for her first foraging trip. During early lactation, foraging trips can last 3-5 days but will often extend to 8-11 days during late lactation. Due to the rich milk supplied by the female, the pup will weigh around 13-16 kg by the time it is weaned at around 10 months old.

Although males are sexually mature at a similar age to females, their lack of size and social maturity means they generally do not mate until they are eight or nine years old. Only a small number of adult males will ever hold a territory, guarding on average 5-8 females. Territories can be defended for as long as 70 days, during which time the male will not feed at all. While such prolonged territory defence is energetically expensive, it is likely to pay off when the female mates with the closest male around a week after giving birth.

Adults eat a variety of large energy-rich fish and cephalopods as well as a number of bird species, particularly little penguins Eudyptula minor and short-tailed shearwaters Puffinus tenuirostris. However, juvenile fur seals studied near Kangaroo Island were found to consume more small fish captured in pelagic waters.

Seals visiting Sunshine Coast beaches have been observed both in the water and less frequently hauled out on rocks. Some seals seen close to shore were observed engaging in “teapotting”, a thermoregulation activity where they float with their front flipper grasped between their rear flippers in an effort to raise their body temperature (see images below).

While their visits may be infrequent, New Zealand fur seals contribute to the beautiful biodiversity of the Sunshine Coast region.

Article and images by Julie O'Connor, senior conservation partnerships officer, Sunshine Coast Council

References

Arnould, J P Y, Littnan, CL. and Lento, GM. 2000. First contemporary record of New Zealand fur seals Arctocephalus forsteri breeding in Bass Strait. Australian Mammalogy 22: 57-62

Australian Museum at https://australianmuseum.net.au/new-zealand-fur-seal

Goldsworthy D. 2006. Maternal strategies of the New Zealand fur seal: evidence for interannual variability in provisioning and pup growth strategies. Australian Journal of Zoology 54: 31-44

Page B, McKenzie J and Goldsworthy S. 2005. Dietary resource partitioning among sympatric New Zealand and Australian fur seals. Marine Ecology Progress Series 294: 283-302

Van Dyck, S. and Strahan, B. (eds). 2008.sssss The Mammals of Australia 3rd ed, New Holland Publishers, Sydney, Australia.ss.