GE fish - a potentially devastating environmental hazard

Genetically engineered (GE) fish present poorly understood but potentially devastating hazards to the environment and the livelihoods of those who fish for a living, writes Greenpeace's Doreen Stabinsky.

Dr Stabinsky has a PhD in genetics from the University of California at Davis, and is a visiting professor of environmental policy at the College of the Atlantic in Bar Harbor, ME.

The recent escape of over 100,000 salmon from a fish farm off the coast of Maine slipped by the public eye with surprisingly little comment. Undoubtedly, this release will threaten North America's few remaining wild stocks of Atlantic salmon, which are already listed as endangered. Many runs of Pacific salmon are in the same precarious situation. Farm-bred salmon present a major threat to wild salmon as they compete for food and mates. Additionally, interbreeding between farmed and wild salmon reduces the genetic diversity of wild populations. But things promise to get much worse if the federal Food and Drug Administration allows genetically engineered (GE) salmon, engineered to grow two to three times as fast as current farm-bred versions, to be commercially farmed in pens along our coasts.

Scientists do not fully understand the extent of the hazards posed to the environment by GE fish, but studies of the feeding and mating behavior of engineered fish give some clues. Currently, scientists cite two main hazards posed by the release of genetically engineered salmon into oceans and streams. First, because of their rapid growth rate and increased appetite, these GE fish have a greater ability to compete for food. Researchers at Fisheries and Oceans Canada have demonstrated that coho salmon engineered with a growth hormone gene eat almost three times as much food as their non-transgenic tank-mates, raising the concern that escaped GE salmon could out-compete native salmon in natural streams.

Second, genetically engineered fish can be very successful at getting mates, but may have other characteristics that reduce the chances their offspring will survive. Professors William Muir and Richard Howard, of Purdue University, have dubbed this the "Trojan Gene" effect. They genetically engineered a type of fish, the medaka, and found GE medaka were more successful at mating than non-GE medaka, due to their larger size. At the same time, the offspring of the GE fish were much less likely to live to maturity. The researchers then showed through computer modeling that introducing a mere 60 of these GE fish into a population of 60,000 could push that population to extinction. Just like a Trojan horse, the novel gene that seems to be a gift is in fact a hazard. Scientists believe that fast-maturing, GE salmon would have the same type of mating success; defects associated with their fast growth, such as head and jaw deformities that interfere with feeding, could be the Trojan characteristics that reduce the survival of offspring in the wild.

Last year a U.S. company, A/F Protein, applied for U.S. Food and Drug Administration (FDA) approval to commercialize its genetically engineered salmon. The FDA determined that its Center for Veterinary Medicine is the appropriate body to approve the release of these fish into the environment, because the fish is engineered to produce a new hormone in its body - i.e., an animal drug. But the FDA is simply not equipped nor qualified to assess the ecological hazards of genetically engineered fish.

Concern about the impacts of genetically engineered salmon is being voiced by many, from scientists, to conservationists, to the salmon industry. The British Columbia Salmon Farmers' Association and the Atlantic Salmon Federation have voiced strong opposition to the use of genetically engineered fish varieties, until they are demonstrated safe for the environment. A recent report by the Royal Society of Canada recommended a moratorium on the rearing of GE fish in aquatic facilities. The American Society of Ichthyologists and Herpetologists (fish, reptile and amphibian biologists) recently also passed a resolution strongly favoring such a moratorium.

Genetically engineered salmon pose unacceptable environmental risks by needlessly threatening the last remaining stocks of our wild salmon species. These novel fish don't belong in our rivers and oceans.