Bridges Trade BioRes • Volume 9 • Number 15 • 4th September 2009

New Research on GM Fish Urges Caution

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Because of the threat they pose to the natural environment, transgenic fish should only be bred in closed systems on land, a new study from researchers at the University of Gothenburg in Sweden says.

The study, which looked at the environmental effects of genetically modified organisms (GMOs) in the fish farming industry, was commissioned by the EU to begin addressing concerns surrounding transgenic fish.

While genetically modified fish have the potential to boost commercial fishing and reduce pressures on overexploited fish stocks, the study raises serious concerns about the ability of natural populations to compete if transgenic fish escape and establish themselves in natural stocks.

By introducing transgenes, or genes from other organisms, researchers have created fish that grow faster and are more resistant to disease. While these characteristics could increase production and yields for commercial fish farming, the Gothenburg study indicates that when these fish escape, they have a much greater effect on the environment than hatchery-reared non-transgenic fish.

A politically sensitive issue for many of its member states, the EU continues to struggle with the issue of GMOs. In the case of transgenic fish, many are worried about the possibility that those that are bred to be resistant to environmental toxins could accumulate and pass the dangerous substances on to consumers. Additionally, questions persist regarding the effects that higher levels of growth hormone in the fish will have on humans when consumed.

Using transgenic salmon and rainbow trout, researchers simulated escapes within an enclosed laboratory. They found that transgenic fish survive better than non-transgenic fish when there is a shortage of food, and benefit more from increasing water temperatures. Researcher Fredrik Sundström says these advantages are due to the greater ability of the genetically modified fish to compete and convert food.

Researchers are quick to point out that simulating natural environments within a laboratory setting is complicated and makes predictions difficult. However, Sundström advised that general international consent should be reached before commercial farming of transgenic species moves forward.

One option, the report says, is to farm the transgenic fish on land making escape impossible. At the very least, Sundström says fertile fish should be kept in a closed system.

Although no country has permitted commercial farming of transgenic fish, several applications for such operations are under consideration by authorities in both the EU and the US.

Transgenic fish are created by transferring genes to fish from other species, including human beings. So far, researchers have genetically modified some twenty fish species, including carp, salmon and catfish.

ICTSD Reporting; “Risks Involved With Transgenic Fish,” UNIVERSITY OF GOTHENBERG, 25 August 2009.