More than 10 per cent of Australia's shark species are at risk of extinction, an Australian government report revealed .

The National Environmental Science Program (NESP) marine biodiversity hub published the first-ever complete assessment of extinction risk for all Australian sharks, rays and ghost sharks (chimaeras).

It found that Australia is home to more than a quarter of the world's cartilaginous fish species, with 182 sharks, 132 rays and 14 chimaeras calling Australian waterways home and that 12 per cent, or 39 species, are facing extinction.

While Australia's risk is considerably lower than the global level of 37 per cent, it does raise concern for the 39 Australian species assessed as having an elevated risk of extinction.

Around Australia, many of threatened sharks and rays are not commercially important so these are largely 'out of sight, out of mind', but they require protection at national, state and territory levels.

There are positive signs of protection and management working for some iconic species such as the White Shark and Grey Nurse Shark, although the assessment shows that these species "remain threatened".

The landmark report found that Australian waters also act as a refuge for 45 species that are threatened in other parts of the world including the giant guitarfish.

Note : Sharks, among the fiercest predators in the ocean, are also some of the most vulnerable. Three-quarters of open-ocean shark and ray species are threatened with extinction, primarily because of overfishing.

Being top predators that help keep the food web in check, it would logically follow that they are keystone species— species that have a disproportionately large effect on their ecosystems. Without keystone species, ecosystems change or even disappear.

By keeping their environments stable and resilient, sharks could help slow climate change and dampen the effects of extreme weather events, such as heat waves and hurricanes.