Aquaculture for all

Genetic Biocontrol: The Future Of Managing Invasive Fish?


Experts from Australia, Norway, South Africa, Malaysia, the UK, Canada, and the US gathered in Minneapolis in June to explore the use of transgenic methods in controlling aquatic invasive species, reports Leah Sharp for the Minnesota Sea Grant.

A shared understanding of genetic biocontrol issues worldwide was perhaps the most valuable outcome.

The idea for the International Symposium on Genetic Biocontrol of Invasive Fish was born out of frustration by US Fish and Wildlife managers over the lack of effective control tools for invasive fish. The managers knew work was being done in the US and Australia to create genetically modified fish whose release into the wild (and subsequent interbreeding) would disrupt the survival or reproduction of invasive species.

At the symposium, organised by Minnesota Sea Grant, nearly 80 participants learned about the current status of biocontrol technology and the issues surroundings its use. The first day focused on the myriad ways in which genetic and chromosomal manipulations could be used to create genetically modified fish as biocontrol agents.

Ron Thresher, from the Commonwealth Scientific and Industrial Research Organisation (CSIRO) Australia, talked about introducing a gene into wild carp populations that would result in carriers having only male offspring. John Teem, from the Florida Department of Agriculture and Consumer Services, presented the idea that researchers could manipulate a fish's sex-determining chromosomes thereby altering the sex ratio of the fish's offspring. Both of these genetic alterations would cause an invasive population to become increasingly male-dominated and, as the number of females decreased, the population's viability would also decrease.

The exciting potential these methods offered was tempered by the fact that most are far from field-ready. Keenly aware that mobile, reproducing organisms would be difficult…if not impossible…to recapture, symposium participants discussed the risks associated with setting genetically modified organisms loose in the environment.

Formerly with Sea Grant, Anne Kapuscinski, Sherman Fairchild Distinguished Professor of Sustainability Science at Dartmouth College, addressed "environmental risk assessment." Keith Hayes, CSIRO Australia, helped shed light on how to incorporate the uncertainty inherent in this new technology into quantitative calculations, a crucial step in determining the risks associated with the use of genetically modified organisms in the wild.

Discussions about the murky regulatory arena across state, federal, and international jurisdictions dominated the discussions on the third day of the symposium. Representatives from the US Food and Drug Administration, the US Fish and Wildlife Service, the Cartagena Protocol on Biosafety, and others talked about the perspectives of their various agencies on the use and regulation of genetic biocontrol technology. While it remained unclear what roles the various agencies would play, all agreed that working together is key to developing an effective regulatory process.

Post-symposium, teams of participants began writing synthesis papers focused on research needs associated with the technology, environmental risk assessment, and regulations and policy. Academic articles resulting from the symposium will be published in the journal Biological Invasions. Presentations from the symposium and the focus groups preceding the symposium are posted on the Minnesota Sea Grant Web site at:

Many sponsors made the International Symposium on Genetic Biocontrol of Invasive Fish possible; including the US Fish and Wildlife Service, Minnesota Sea Grant, the Great Lakes Protection Fund, Dartmouth College, the US Department of the Interior Bureau of Reclamation, and the Murray- Darling Basin Authority.

May 2011