Marine research agencies and the fishing industry have joined in a three-year study aimed at ensuring the sustainability of shark, ray and sawfish species in the waters off northern Australia.

The study will assess the effects of fishing on shark, ray and sawfish species taken as 'bycatch' in commercial fisheries off northern Australia, as well as the status of sharks targeted by northern fisheries, to identify those most in need of protection.

The three-year study, funded by the Fisheries Research Development Corporation, involves CSIRO Marine Research and research agencies from Queensland, Western Australia and the Northern Territory.

The study is strongly supported by the commercial fishing industry. Fishers will work closely with researchers to provide essential information and to ensure the projects success.

Results of the study will underpin a national approach to the risk assessment of Australian sharks, rays and sawfishes, and contribute to regional, national and international plans for their conservation and management.

Australia's northern shark fishery landed almost 1700 tonnes of target species in 2000, valued at more than $9 million.

But the species composition of such catches is poorly documented, offering few clues to the impact of fishing on the 128 different types of sharks, rays and sawfishes that inhabit the region.

'Sharks, rays and sawfish are vulnerable to fishing as they grow slowly and produce fewer young than most bony fishes,' John Salini of CSIRO Marine Research said.

He said the study would establish consistent and accurate identification and reporting of the sharks, rays and sawfish caught in all target and non-target fisheries (such as barramundi and mackerel).

In each state, trained observers would accompany fishing boats to identify and record the catch, and to collect biological information and samples for genetic analysis.

Commercial fishers would be trained to record these details on an ongoing basis.

'These catch and biological records will be combined with ecological knowledge to enable accurate stock assessments of the major target species, such as the blacktip shark and the spot-tail shark,' Mr Salini said.

'We will also use the information to identify potentially higher risk or vulnerable species that may require coordinated management initiatives.' The study will also gather information on the reproduction and growth of northern sawfish species so their populations can be assessed.

Tropical sawfish species are at risk worldwide, with little known about their accidental capture. Two northern Australian species, the dwarf sawfish and the green sawfish, both caught in gillnets, are listed as endangered.

'Sawfish in general seem to be heavily affected by commercial fishing, the ones that we know about anyhow,' CSIRO's John Stevens said.

'They use their saws to grub around on the bottom for invertebrates, and even to slash at schools of fish. They make great weapons, but can become tangled any form of netting.'

The United Nations had developed an International Plan of Action for the Conservation and Management of Sharks amid concern about overfishing.

In Australia, a National Plan of Action for the Conservation and Management of Sharks is coordinated by the Department of Agriculture, Fisheries and Forestry, and the 1999 Environment Protection and Biodiversity Conservation Act requires export fisheries to be assessed for their ecological impacts.

More information from:
John Salini, CSIRO Marine Research 07-3826 7244
john.salini@csiro.au

Bryony Bennett, CSIRO Marine Research 03-6232 5261
bryony.bennett@csiro.au.

Kylie Paulsen,
FRDC 02-6285 0415
paulsenk@frdc.com.au.