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FISHY FORENSICS TO SOLVE MACKEREL MYSTERY10 August 2005
Ear-bones, parasitic worms and DNA will be used to fish for evidence about grey mackerel populations in the tropical waters of northern Australia, as part of a new $1.9 million research project co-ordinated by CRC Reef Research Centre and funded by the Fisheries Research and Development Corporation. Scientists suspect that there may be several different populations of grey mackerel in northern waters, and that they may even migrate long distances from Queensland to Northern Territory waters. The commercial and recreational catch of grey mackerel in the Gulf of Carpentaria is growing, and fisheries managers are worried that without more information to manage the fishery sustainably it could experience a dramatic fall in catch. “Understanding the size and movements of grey mackerel populations is vital for both managers and fishers,” according to CRC Reef Fishing and Fisheries Project Leader Dr Gavin Begg, from James Cook University. “This research will help to ensure the fishery is managed sustainably, and reduce uncertainty for fishers who are investing in the fishery.” With the help of commercial fishers, who will be providing the researchers with access to their mackerel catch, three techniques will be trialled to find out how groups of grey mackerel interact. Professor Bob Lester from The University of Queensland will use tiny parasitic worms carried by the fish to find differences between groups. “The mackerel pick up most of these parasites from smaller fish in their diet, and the difference in numbers and species of parasites can give us a clue to whether the mackerel have lived in the same areas or not. The parasites are harmless to humans, and collect around the stomach and gills of the fish, not the parts of the fish that people eat,” Prof Lester said. Grey mackerel ear-bones, or ‘otoliths’ could also show where the fish have been living, and what they have been eating. These clues emerge from trace elements in the otoliths, which will be investigated by scientists from Fisheries Western Australia. DNA extracted from the fins of the fish will help find long-term population differences in grey mackerel. Queensland Department of Primary Industries and Fisheries will analyse genetic markers to discover whether there are genetically separate populations of grey mackerel in northern Australia. The $1.9 million project is expected to run for three years and aims to use these techniques to discover where grey mackerel populations live, and if they migrate to different areas. This information will then be used to define appropriate management frameworks for grey mackerel to be used by Queensland and Northern Territory fisheries agencies. The project is a collaboration between CRC Reef, Fisheries Western Australia, Northern Territory Department of Primary Industry Fisheries and Mines, Queensland Department of Primary Industries and Fisheries, and The University of Queensland. More information: |
