Scientists from AIMS, Charles Darwin University and the Northern Territory Department of Primary Industry, Fisheries and Mines, are working in collaboration with commercial fishermen and the Northern Territory Seafood Council to monitor shark populations in Australia’s northern waters.

The diverse team of managers, fishermen, and scientists, have tagged over 1000 sharks off the NT coastline in an effort to assess current shark populations and to determine sustainable catch levels for the fishery.

Increasing global concern regarding depleting shark populations prompted the commercial industry and research partnership to request funding from the Australian Research Council for the large-scale study which will run for 3 years.

Dr Iain Field, the leader of the tagging project and a postdoctoral fellow at AIMS and CDU, said the effort is an excellent example of an effective partnership between science and industry and is likely to benefit the fishery as well as local shark populations which play a vital role in stabilising marine ecosystems.

"Although our research group has tagged a large number of sharks, the vast scale of tagging required would not be possible without the help of the fishermen. It’s great to have their support and know that they are interested and involved in helping develop management and monitoring tools for their fishery," said Dr Field.

Of 125 nations with commercial shark fisheries, Australia is one of only 5 nations that actively manage their shark fisheries. In NT waters sharks are caught by recreational, Indigenous and commercial fishermen. The fisheries are small and well-managed, although there is a potential threat from a large scale illegal fishery that is harvesting sharks in northern Australian waters.

Dr Field noted that "with such a large number of tagged sharks out there we are now beginning to see the sharks recaptured. So far we have seen shark recaptures from recreational and commercial fisheries including the NT barramundi fleet and the northern prawn fishery, as well as from our shark fishermen.

"It’s really exciting knowing that tagged sharks are being recaptured and hopefully released alive with their tags in place. This will give us a much better idea of how the sharks are responding to the fisheries because we can calculate an animal’s probability of being caught."

Individual sharks are being marked with two highly visible plastic tags. When they are caught again by commercial or recreational fishermen, the sharks’ growth, survival and movement data will provide valuable information for the scientists.

Fishermen catching tagged sharks are asked to report the tag colour and number, which species of shark was caught, the date and location of the catch, and if possible, photograph the fish and release it alive. A reward is offered for the information.