GM Kills Sex Drive in Trout and Makes Them Easier to Catch


With diminishing fishery resources and increasing food demand from an ever-growing human population, it is not surprising that aquaculture corporations and multinational biotechnology are funding research and development into genetically modifying fish.

Genetically engineered fish are bred to enhance their commercial viability, like enhanced growth rates, feed conversion efficiency, and tolerance for certain environmental conditions.

Farm-raised trout, sought after mainly by recreational anglers, are genetically modified to prevent negative ecological impacts such as transfer of undesirable genes to native trout population.

Killing sex drive

One recent study done in Great Britain has successfully modified farmed trout, preventing them to interbreed with native trout population. It was prompted by concerns regarding the ecological effects of the yearly restocking of rivers and lakes with 900,000 farm-raised brown trout.

The problem is the interbreeding of these fish with the wild ones, passing on undesirable genes. The scientists found a solution: genetically engineering the farm-reared fish with an extra set of chromosomes. "We knew one answer could be to release so-called triploid fish – which have been altered to have an extra set of chromosomes," said Environment Agency’s head of fisheries Dr. Dafydd Evans.

Easier catch

In addition to rendering the fish infertile, another effect of genetically altering farm trout is that it makes them easier to hook, certainly a bonus for Britain’s two million recreational anglers.

"It is an unexpected bonus," Evans said. "It means anglers can catch more and so get more sport out of them." Dylan Roberts, the trust’s head of fisheries, said, "They are bred for eating and have lost many of the genes vital for survival. We don’t want them giving those genes to native populations."

Roberts tagged around 1,000 triploid farmed fish and another 1,000 farmed fish with normal gene and released them into the rivers. He then conducted a survey, asking anglers how many of each trout they caught and how the fish fought. Results show that genetically modified trout are easier to catch. One theory to explain this occurrence is that having lost their sex, engineered trout focus on eating. This makes them less active, thus easier to hook.


The practice of releasing with farm-raised trout in rivers and lakes is highly controversial among environmentalists. Many critics argue that releasing them for capture and recreation is similar to releasing cows into the woods and then shooting them down.

Supporters, on the other hand, argue that the recreational fishing industry is generating millions of pounds. They say that this sport helps rural areas while offering urbanites a great hobby that gets them outdoors.

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