Australian Sea Lion(Neophoca cinerea)
They are also known as the Australian sea-lion or Australian sealion. Males are enormously large, reaching a huge size: sometimes they can be 3 times bigger than females. Other distinctive features of these sea lions are: muzzles - tapered, long and narrow; sagittal crests on their skulls; extremely small ears, lying close to their heads. Males of the Australian sea lion are dark brown in color whereas females are silver. Young are also dark brown, having dark mask on their face and a pale crown.
Habitat
Australian sea lions live mainly in isolated bays as well as on ocean and sandy beaches. The area of their distribution includes islands, offshore of Australia; these sea lions are found from Western Australia to islands in southern Australia. Due to being excellent climbers, the Australian sea lions can be seen on cliffs, sometimes climbing as high as 30 meters.
Diet
Australian sea lions are carnivores (piscivores, molluscivores). Their regular diet includes octopus, blue-throated wrasses, squids, fairy penguins and cuttlefish. They also eat certain species of fish such as small sharks, rays and whiting.
Breeding
The Australian sea lions are polygynous, meaning that one male can mate with multiple females. Males engage in fights, in order to be allowed to mate with females. Breeding cycle of these sea lions is about 1.5 year while gestation period lasts 11 months, after which a single baby is born. The pups usually live with their mother during the first year after birth. They often join groups of other pups, where they play together and participate in mock battles. Weaning takes place at the age of 15-18 months while sexual maturity is reached as the age of 3-6 years.
Population
The overall population of the Australian sea lions is currently decreasing, and in the UICN Red List the species is classified as Endangered (EN). The total number of population varies from 12.290 to 13.090, including 6.500 mature individuals.
Threats
One of the major threats to this species is fishermen. The sea lions frequently become entangled in fishing nets and die there. Chemical pollution, noise pollution, oil spills as well as diseases are among factors, threatening the sea lions’ population. On the other hand, sealing has caused large reduction of the overall population. Other important threats are human disturbance, intentional killings, climate changes, depletion of suitable prey, loss of habitat and aquaculture operations.
Conservation
This species is protected in Australia by State Conservation agencies under numerous independently enacted state laws, the earliest dating back to 1889. The Environment Protection and Biodiversity Conservation Act, 1999 provides protection for all pinnipeds in Australia. The Australian Sea Lion was listed as a Threatened species in the Vulnerable category under that Act in 2005. It is listed as a protected species (rare) in South Australia under the National Parks and Wildlife Act, 1972. In Western Australia they are protected under section 14 of the Wildlife Conservation Act, 1950 and are listed as specially protected in Western Australia under the Wildlife Conservation (Specially Protected) Fauna Notice 2005. Between 2010 and 2012, the Australian Fisheries Management Authority (AFMA) introduced a range of management measures into the shark gillnet component of the Gillnet Hook and Trap (GHAT) fishery to mitigate the impacts of bycatch mortality on Australian Sea Lion populations off South Australia. This followed research that integrated an on-board independent bycatch observer program on gillnet vessels, and an extensive Sea Lion satellite tracking and spatial modelling program (Goldsworthy et al. 2010). The management measures introduced include spatial closures (most between 4–10 nm) excluding the fishery around all Sea Lion colonies off South Australia, and bycatch trigger limits that place a cap on the total numbers of Sea Lions that are permitted to be caught within areas of the fishery, which if exceeded result in extended (18 month) fishery closures. Given there is 100% observer coverage in this fishery, mostly through electronic monitoring, there is high compliance and most Sea Lion bycatch is now reported in fishery logbooks. Additional management measures, such as switching gear to hook and line, are being considered. Bycatch of Australian Sea Lion pups and juveniles in Rock Lobster pots has been largely mitigated through the introduction of Sea Lion excluder devices in the Western Australian and South Australian Rock Lobster fisheries.