Genetically Altered Trout Approved for Release in U.K.

April 30, 2008

Plans to pour tankfuls of genetically altered fish into wild lakes and rivers have been given the go-ahead in the United Kingdom after conservation scientists backed the project.

According to a recent study, releasing the modified fish for anglers to catch is a better option than traditional trout farming and may even benefit native trout populations.

That's because the fish have been engineered to be sterile, so they won't breed with vulnerable wild strains.

These so-called triploid trout have three sets of chromosomes in their cells instead of the two sets normally found in diploid animals.

The two-year study, led by Dylan Roberts of the U.K.'s Game and Wildlife Conservation Trust, investigated the impact of releasing triploid trout on native populations at 90 river sites in England and Wales.

The government's Environment Agency (EA) approved the plan last week following the study's publication.

The EA announced that by 2015 the estimated 750,000 farmed trout introduced each year in fishing waters must consist purely of triploids.

Fitting In

Naturally occurring triploid animals are very rare—triploidy in humans results in miscarriage or death soon after birth.

But viable triploids can be created in fish by subjecting their eggs to high temperatures or pressures to produce the extra set of chromosomes.

According to the study authors, sterile triploids are a solution to the problem of farmed trout interbreeding with native species.

Past studies have shown that "having the domesticated farm gene pushed into wild fish can be detrimental to their survival" and their ability to reproduce successfully, Roberts said.

Continued on Next Page >>


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