The Australian sea lion (Neophoca cinerea) also known as the Australian sea-lion or Australian sealion, is a species of sea lion that breeds only on the south and west coasts of Australia. It is monotypic in the genus Neophoca.

Phylogeny

The Australian sea lion is a pinniped most closely related to other species of sea lion and fur seal in the family Otariidae.

Breeding behaviour

The breeding cycle of the Australian sea lion is unusual within the pinniped family. It is an 18 month cycle and is not synchronised between colonies. The duration of the breeding season can range from 5 to 7 months and has been recorded for up to 9 months at Seal Bay on Kangaroo Island.

Bulls do not have fixed territories during the breeding season. The males fight other males from a very young age to establish their individual positions in the male hierarchy and during the breeding season, dominant males will guard females for the right to breed with her when she comes into oestrus. A female comes into season for about 24 hours within 7 to 10 days after she has given birth to her new pup. She will only look after the new pup and generally fights off the previous season's pup if it attempts to continue to suckle from her.

Male Australian sea lions are also known to kill young as an act of defence of territory.

Sea lions on Kangaroo Island beach

Population status and protection measures

There are approximately 14,730 Australian sea lions^[2] following the introduction of the Australian National Parks and Wildlife Act of 1972 which prohibited a harvest that began in earnest as soon as Europeans colonised the continent.

Ecology

Australian sea lions defecate nutrient-rich faeces which may provide an important nutrient source for coastal ecosystems. Metagenomic analysis of the bacterial consortia found in the defecations of Australian sea lions found very high levels of nutrient cycling and and transport genes which may break down the nutrients defecated by sea lions into a form that is bioavailable for incorporation into marine food webs.^[3]

References

Wikimedia Commons has media related to: Australian sea lion

• Shannon Leone Fowler (2005). Ontogeny of diving in the Australian sea lion. Ph.D. thesis. University of California, Santa Cruz.

• Randall R. Reeves, Brent S. Stewart, Phillip J. Clapham and James A. Powell (2002). National Audubon Society Guide to Marine Mammals of the World. Alfred A. Knopf, Inc. ISBN 0375411410.