Fishing for a better solution
Seafood is an integral part of mankind's diet, but pollution, growing populations and improving ways of catching fish are straining the ability of wild fisheries to meet demand. Queensland scientists believe they have come up with a world-first solution to the problem.
It's essential to determine the rate at which we harvest wild fish. One way to do it is to tag a known number of fish, then record how many are subsequently harvested (If, say, 50 per cent of tagged fish are caught then the harvest rate is 50 per cent and managers would most likely reduce the allowed catch next year.) To achieve this without major stress on individual fish, scientists from Queensland's Department of Primary Industries and Fisheries and their Northern Territory colleagues are working on the world's first application of gene marker technology to estimate harvest rates.
Their project tags fish by taking a DNA fingerprint. A small piece of tissue is obtained when the fish strikes a lure with a hollow hook. The copper hook straightens out when struck, which releases the fish. The tissue is genotyped to determine the DNA fingerprint of the fish.
This system allows scientists to establish a DNA database so that when fish are later caught, they can be identified by matching DNA records.
Dr Jenny Ovenden, Senior Fisheries Geneticist with Queensland's Department of Primary Industries and Fisheries, said results so far have been very encouraging.
"We've been testing the technology on Spanish mackerel with the help of our colleagues in the Northern Territory and it's working well. If all goes to plan, we will identify our first recaptures this year.
"The project has significant international application for fisheries management and already we've been contacted by Canadian fisheries scientists who are very interested.
"We believe gene marker technology will be a simpler, smarter and more accurate way to estimate the best possible harvest rate of fish populations," Dr Ovenden said.
"The process will enable fisheries resource managers to set catch limits at the most sustainable and economically efficient levels."
Information: jennifer.ovenden@dpi.qld.gov.au
Last reviewed 19 January 2006