Often found lounging on rocks or riding waves, the curious and playful nature of fur seals makes encountering these species in the wild incredibly exciting. The Australian fur seal is a skilled hunter, torpedoing through the waters of the Bass Strait with their streamlined body, foraging for fish, squid, octopus and cuttlefish. Distinguished by their small external ears (unlike “true” seals with internal ears), large popping eyes, pointed snout and short, backwards facing whiskers, the Australian fur seal make the Bass Strait their own personal foraging ground. Seals hunt expansively through all levels of the water but they prefer to forage along the bottom of the continental shelf where depths can reach up to 200 metres. Keep an eye out, as you may catch a glimpse of them surfacing for air.
Australian fur seals are benthic (sea floor) foragers and predators, but they also roam the shallows and regularly come to the surface for air. Here an Australian fur seal pops its head up in the Southern Ocean just west of the Bass Strait near Port Fairy. Photograph by Ed Dunens. CC BY 2.0.
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The Bass Strait supports the largest breeding colonies of Australian fur seals, with six islands off the coast of Victoria and four off the coast of Tasmania. Among these locations, Seal Rocks off Phillip Island is the most productive, supporting thousands of individuals at any one time and is a perfect place for young pups to gain the confidence and skills they need to survive.
Seals are found in oceans around the world and are common in Australian waters. Four seal species once inhabited the Bass Strait: the Australian fur seal, the New Zealand fur seal (also known as the long-nosed fur seal), the Australian sea lion, and the southern elephant seal. In the late 1700s and early 1800s, over-exploitation from commercial sealing led to a dramatic decline in seal populations. Millions of seals were hunted for their coats and oil, narrowly escaping extinction. Post-sealing, the Australian fur seal emerged as the last surviving seal species in the Bass Strait, gradually recovering under protection since 1975.
Although it has ‘New Zealand’ in the name, the New Zealand fur seal, also known as the long-nosed fur seal, was once as much at home in the Bass Strait as its Australian counterpart, before being driven out by sealing. Since the late 1990s, small numbers of New Zealand fur seals have started to recolonise the area. But after sealing ended neither the Australian sea lion nor the southern elephant seal returned to the strait.
The New Zealand fur seal is commonly mistaken for the Australian fur seal, as both species look quite similar and haul-out together outside of breeding, meaning they come to shore together to moult and rest. If you know what you are looking for, however, their distinctive body shape, colouration and behaviours set them apart.
The Bass Strait was once home to four seal species, but nineteenth century commercial sealing drove three of those species locally extinct. This engraving from 1807 depicts southern elephant seals on the shores of King Island, an island in the western Bass Strait, with the buildings of a sealing settlement in the background. Engraving by Victor Pillemont. Courtesy of National Library of Australia.
Southern elephant seals were once found in the Bass Strait but were driven out by nineteenth century commercial sealing. Today southern elephant seal colonies are scattered on islands in the southern hemisphere, including Macquarie Island, pictured here. Now considered a vulnerable species, elephant seals never returned to the Bass Strait. Photograph by Kimberley Collins. CC BY 2.0.
The Australian sea lion was heavily hunted to the point of near extinction by commercial sealing in the late 1700s and early 1800s. Now considered an endangered species, sea lions never returned to the Bass Strait. Australian sea lions still live in Australian coastal waters in Western Australia and South Australia. The largest colony is on Kangaroo Island, pictured here. Photograph by Matthew Fuentes. CC BY-NC-ND 2.0.
Australian fur seals display a scalloped trailing edge on the first flipper and a large body size, making them the largest of all fur seals. Sexual dimorphism (different sizes between the sexes) is evident among all fur seals, with males (bulls) significantly larger than females (cows). Australian fur seal bulls can reach weights of up to 360 kilograms and lengths of up to 2.5 metres, while cows can weigh a maximum of 120 kilograms and measure up to 1.7 metres. Australian fur seal cows are characterised by their slender body, silver/grey dorsal side, creamy yellow chest and throat and a chocolate brown belly. Bulls, on the other hand, are darker grey to brown with a mane of hair around their necks and shoulders with a pale underside.
Australian fur seals prefer low rocky platforms for breeding, while New Zealand fur seals congregate on elaborate, angular rocky coastlines. Unlike their Australian counterparts, New Zealand fur seals prey on seabirds and penguins and exhibit pelagic foraging, that is venturing out from the shallow continental shelf of the Bass Strait to forage across the open ocean.
Both species breed between October and January, give or take a month, with females giving birth to a single pup in November-December which are weaned 10-11 months later. Both species possess two layers of fur to insulate their vital organs. They periodically moult, meaning their old fur gets replaced with new shiny growth, enhancing waterproofing and insulation for the cold waters of the Bass Strait.
Australian fur seals breed and hunt in the Bass Strait. Here are Australian fur seals on Judgement Rocks, a small unpopulated granite islet in the Kent Group of Islands in the eastern Bass Strait. Photograph by Demelza Wall. Image taken under permit. CC BY-NC-ND 4.0.
The Bass Strait supports the largest breeding colonies of Australian fur seals in the world. Pictured here is an Australian fur seal colony on Tenth Island, part of the Waterhouse Island Group in the Bass Strait off the coast of northeast Lutruwita/Tasmania. Photograph by Demelza Wall. Image taken under permit. CC BY-NC-ND 4.0.
The New Zealand fur seal, also known as the long-nosed fur seal, was once common in the Bass Strait but was hunted out by commercial sealers in the nineteenth century. New Zealand fur seals are found throughout New Zealand and off the coast of Western and South Australia. Since the 1990s small numbers have begun to return to the Bass Strait. Pictured here are New Zealand fur seals in Doubtful Sound, New Zealand. Photograph by Vince O’Sullivan. CC BY-NC.
An Australian fur seal pops its head up out of the water while a shy albatross looks on. Photograph by Ed Dunens. CC BY 2.0.
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Further reading
Arnould JPY, Littnan CL & Lento, GM (2000) ‘First contemporary record of New Zealand fur seals Arctocpehalus forsteri breeding in Bass Strait,’ Australian Mammalogy, 22(1) 57-62. https://doi.org/10.1071/AM00057
Atlas of Living Australia (2024) Arctocephalus pusillus : Australian Fur Seal, accessed 30 June 2024.
Atlas of Living Australia (2024) Arctocephalus forsteri : New Zealand Fur Seal, accessed 30 June 2024.
McIntosh RR, Sorrell KJ, Thalmann S, Mitchell A, Gray R, Schinagl H, Arnould JPY, Dann P, Kirkwood R (2022) ‘Sustained reduction in numbers of Australian fur seal pups: Implications for future population monitoring’, PLoS ONE 17(3):e0265610. https://doi.org/10.1371/journal.pone.0265610
