Australian Sea Lions
Let’s dive deep into our Australian Marine Parks to learn and play with the Australian sea lion
Australian sea lions are one of the rarest sea lion species in the world, and are only found in one country - Australia!
Sea lions have been nicknamed the puppies of the ocean, as they love to play with each other and their environment. How lucky are we to have these mischievous creatures right on our back doorstep?
If you look in Australian Marine Parks you might just get to see or even swim with an Australian sea lion.
South Australia is home to more than 80% of the total population of Australian sealions with 48 breeding sites found along the state’s coastline.
Unfortunately, over the last four decades we’ve seen a 64% decline in their population and there are now less than 11,000 Australian sea lions left, so protecting them is more important than ever . 1
Importance of Marine Parks
The majority of Australian sea lion breeding colonies lie within protected waters, forming parts of various marine parks across South Australia and Western Australia.
Marine parks help protect key foraging areas and as we learn more about what and where Australian sea lions eat – this can provide an important tool for ongoing and future management and protection. We need to make sure marine parks are maintained and respected Australia-wide, to ensure that species like Australian sea lions are given the best opportunity possible to recover and thrive.
Marine parks provide safe zones for threatened species, providing protection from some of the potential human threats.
Australian sea lions are mobile mammals so can be seen across all of South Australia’s marine park networks. However, their home colonies are often seen in the West Coast Bays Marine Park, Thorny Passage Marine Park, Sir Joseph Banks Group Marine Park, and both the Western and Southern Kangaroo Island Marine Parks.
Classification
The Australian sea lion is a pinniped, and part of a group known as ‘eared’ seals. Australian sea lions are most closely related to fur seals, and other sea lion species, together these animals make up the family Otariidae. They are defined as mammals which can use their flippers to both move through the water, as well as walk on land.
Physically, Australian sea lions share particular features with other sea lion species, these include short flippers and a bulky body, and short fur which covers their body. Within their genus Neophoca, they are the only currently living (extant) species.
Kingdom – Animalia
Phylum – Chordata
Class – Mammalia
Order – Carnivora
Family – Otariidae
Genus – Neophoca
Species – Neophoca cinera
Distribution
Where can you find the Australian sea lion?
Australian sea lions can only be found in one place in the world – Australia!
You can spot them on small islands off the South Australian coast and the southern half of Western Australia, and on a few mainland sites at cliff bases. Many of these islands form parts of the South-west marine parks network, which act as productivity hotspots and provide rich foraging grounds for the sea lions. Marine parks which contain sea lions include the Great Australian Bight, Western Eyre, and the Western and Southern Kangaroo Island marine parks.
Historically, the Australian sea lions existed all the way around the southern half of Australia, including some colonies on offshore islands in the Bass Strait, Victoria. Following European settlement, targeted fishing from sealers reduced Australian sea lion numbers until legal protection was instated between 1890-1919 for Western Australia, South Australia, and Victoria.
Populations
There are only 10,000-11,000 Australian sea lions left, and more than 80% of that population lives in South Australian waters. 1 Sea lions are non-migratory, meaning they stay in large breeding colonies close to their birthplace. Australian sea lions like to form social groups – with sub-groups of 10-15 individuals common.
Australian sea lions only leave their colony for one thing…. food. When hunting they have been recorded to travel up to 340 kilometres from their colony – pretty far just to get something to eat! Often, this hunting occurs in marine parks, where protected waters can flourish and provide plentiful hunting grounds for Australian sea lions.
Habitat
Australian sea lion breeding colonies often occur on sandy beaches in the protected bays of offshore islands. Here, is where they spend most of their time, breeding, sleeping, and relaxing.
Sea Country
Australian sea lions occur throughout First Nations’ Sea Country. Sea Country includes all oceans, beaches, land, and freshwater coastline. It covers all plants and animals, including the Australian sea lion.
Sea Country encompasses the weather, sky, and People. It includes all living things, beliefs, values, spirits, and cultural obligations from coastal areas.
Australian sea lions are mobile species, so are not tied to one particular Sea Country. However, they are particularly important in providing habitat in Wirangu, Barngarla, and Nauo Sea Countries, as well as on Karta Island.
Role in the ecosystem
What do Australian sea lions eat?
Australian sea lions are mostly carnivorous, benthic feeders – meaning they eat off the seafloor.
Their diet usually includes (1) fish; including leatherjackets, trevally, and red mullet, (2) cephalopods, made up of various octopus, squid, and cuttlefish species, as well as (3) ray species. 4
As apex predators, Australian sea lions play an important role in marine ecosystems by helping balance the population size of their prey. Marine parks provide protected locations for the feeding grounds of Australian sea lions.
The Twilight Marine Park in the Great Australian Bight is full of seafloor-dwelling prey that Australian sea lions can feast upon – including octopus, cuttlefish, small sharks, and rays.
Catching their prey
Australian sea lions love to duck down deep to catch their prey – with one sea lion even recorded as diving 250 metres!
Usually, diving depths vary depending on the age and sex of the animal, with juveniles rarely diving deeper than 90 metres, cows not much deeper than 130 metres, and bulls diving the deepest down to 150 metres. 5 The time they spend diving for food varies, however, is not usually more than eight minutes. 6, 7
How long can you hold your breath? Did you know that Australian sea lions can hold their breath for up to 40 minutes!
What eats Australian sea lions?
Australian sea lions are prey for large marine predators such as white sharks and maybe even killer whales. 8 The sea lion pups can also be hunted by smaller shark species. Many of these large predators also live in the marine parks spread across the South-west marine parks network, allowing for important ecosystem balance.
Reproduction
Australian sea lions live in breeding colonies, with many males and females together. During the breeding season, mature bulls fight for the cows, often becoming aggressive towards each other. Females are sexually mature at 4.5 to 6 years old, and males at 6 years. 9
Australian sea lions have a non-annual breeding cycle, meaning breeding every 18 months or so. 10 This is likely due to their long gestation time, as females are pregnant for around 14 months - 5 months longer than any other pinniped species in the world!
Following the birth of the pup, they are nursed by their mothers until they are between 18 months and 3 years old.
Breeding sites
Australian sea lions like to stay nice and close to their home breeding colony. This means that breeding usually takes place between bulls and cows from the same breeding colony - causing little genetic exchange between different Australian sea lion groups. 11
There are more than 80 identified Australian sea lion breeding sites across Australia, with a total pup production of around 2,700 individuals. 12 The majority of these pups are born in South Australia (around 2,200), while the remaining 500 are split between two meta-populations in Western Australia. 12 Surveys in South Australia have found many breeding sites to have declining pup numbers, on an average of 2.0% per year. 12
Some of these breeding sites are in marine parks in the South-west marine parks network, which provide important safe grounds for breeding to occur without human pressures.
Tourism
Seal Bay Conservation Park , Kangaroo Island, is the only place in the world where people can walk through a wild Australian sea lion colony. With more than 115,000 people visiting Seal Bay every year, this colony is the most accessible place for tourists to come and learn about the third largest colony of Australian sea lions.
Importantly, Seal Bay is one of the best-studied breeding colonies in Australia – over 25 years of scientific research has provided important information about the health, diet, breeding, and population biology of these unique creatures. This scientific context helps us to track population numbers, and better investigate why Australian sea lions are in decline.
The Seal Bay Conservation Park is located close to the Southern Kangaroo Island Marine Park, which provides important protected areas for the sea lions to hunt in while they are at their breeding grounds.
Swimming with Australian sea lions
You can also swim with sea lions with various eco-tourism companies! These tours operate under tourism permits that include a series of special guidelines for the safety of sea lions and swimmers in the water. Providers of swimming with sea lion experiences include Kangaroo Island Marine Adventures , as well as Baird Bay Ocean Eco Experience , and Calypso Star Charters off the Eyre Peninsula coast.
Environmental Threats
In December 2020, the Australian sea lion was officially up-listed from its vulnerable status to endangered. 13
Historical fishing pressure
Although the Australian sea lion is now protected, historical hunting has restricted the range of Australian sea lions, as they are thought to previously occur all the way around the Bass Strait.
Key threats that Australian sea lions face are caused by gillnets. Sea lions can become caught in the nets, causing death and potential population decline. Other reasons why sea lion populations are lowering could be contributed to interactions with the rock lobster industry, entanglement in marine debris, habitat degradation, human disturbances to colonies, disease, general pollution, prey depletion, and climate change. Likely, it is a combination of these pressures that are causing the decrease in Australian sea lion numbers.
This factsheet is part of the University of Adelaide's Fab Five project, focused on raising awareness of five fabulous species and the marine parks that help protect them. This 'Our Marine Parks Grants' project received grant funding from the Australian Government.
References
1 . Goldsworthy, S.D., et al., Maintaining the monitoring of pup production at key Australian sea lion colonies in South Australia (2014/15). Final report to the Australian marine mammal center. S.A.R.D.I. Sciences, Editor. 2015, SARDI: Adelaide.
2. Goldsworthy, S.D., Australian Sea Lion, in Australian Sea Lion Encyclopedia of Marine Mammals, B. Wursig, J.G.M. Thewissen, and K.M. Kovacs, Editors. 2018, Elsevier Inc.: United Kingdom, United States.
3. Kirkwood, R. and S.D. Goldsworthy, Fur seals and sea lions. Australian Natural History Series 2013, Collingwood, Victoria.: CSIRO Publishing.
4. McIntosh, R., B. Page, and S. Goldsworthy, Dietary analysis of regurgitates and stomach samples from free-living Australian sea lions. CSIRO Wildlife Research, 2006. 33: p. 661-669.
5. Goldsworthy, S.D., et al., Mitigating seal interactions in the SRLF and the gillnet sector SESSF in South Australia. 2010. p. 213
6. Lowther, A.D. and S.D. Goldsworthy, Maternal strategies of the Australian sea lion (Neophoca cinerea) at Dangerous Reef, South Australia. Australian Journal of Zoology, 2011. 59(1): p. 54-62.
7. Lowther, A.D., et al., Creatures of habit: foraging habitat fidelity of adult female Australian sea lions. Marine Ecology Progress Series, 2011. 443: pp. 249-263.
8. Shaughnessy, P., M. Berris, and T. Dennis, Predation on Australian sea lions Neophoca cinerea by white sharks Carcharodon carcharias in South Australia. Australian Mammalogy, 2007. 29: pp. 69-75.
9. McIntosh, R., Life history and population demographics of the Australian sea lion. 2007.
10. Gales, N.J. and D.P. Costa, The Australian sea lion: a review of an unusual life history, in Marine Mammal Research in the Southern Hemisphere, M. Hindell and C. Kemper, Editors. 1997, Surrey Beatty and Sons: Devon, UK. p. 78-87.
11. Campbell, R.A., et al., Islands in the sea: extreme female natal site fidelity in the Australian sea lion, Neophoca cinerea. Biol Lett, 2008. 4(1): p. 139-42.
12. Goldsworthy, S.D., et al., Assessment of the status and trends in abundance of a coastal pinniped, the Australian sea lion Neophoca cinerea. Endangered Species Research, 2021. 44: p. 421-437.
13. Goldsworthy, S.D., Neophoca cinerea. The IUCN Red List of Threatened Species 2015. 2015.
