A new study maintains that the government is poorly structured to assess possible environmental hazards posed by genetically modified fish.
The study, being issued today by the Pew Initiative on Food and Biotechnology, a nonprofit group, comes as the Food and Drug Administration is considering whether to approve a salmon genetically engineered to grow twice as fast as regular salmon.
The study notes that oversight of the fledgling field is left largely to the F.D.A., which regulates such fish under the rules covering drugs for animals. But the study says that those rules may not allow the agency to consider fully the environmental risks of such fish and that even if it can, it lacks the expertise.
''Regulators will increasingly have to stretch their authority to make old laws and regulations address the evolving next wave of products,'' Michael Rodemeyer, executive director of the Pew Initiative, said in a statement. ''We seem to be treading in uncharted legal waters.''
While some genetically engineered fish are being grown experimentally, none have been approved for use as food. But the F.D.A. is considering an application from Aqua Bounty Farms, a company in Waltham, Mass., for the fast-growing salmon.
The Pew Initiative, based in Washington and backed by the Pew Charitable Trusts, says it is not against genetic engineering but wants to promote public discussion about biotechnology and its regulation.
Indeed, the report said there could be benefits from genetically engineered fish. Faster-growing fish could make fish farming more productive. Efforts are also under way to get fish to produce human drugs like a blood clotting factor, to make fish disease-resistant and to make shellfish that will not provoke allergic reactions.
But there could also be hazards, the report notes. Some studies suggest that if the engineered fish escape from pens they could out-compete wild fish for mates or food, endangering wild populations. Another question is whether the genetic engineering affects the rate at which a fish accumulates toxins like mercury from the environment.
The report, based on a review of legal and scientific literature and interviews with experts, says the F.D.A.'s effort to regulate genetically modified fish as drugs might not withstand a legal challenge. Yet another problem with the arrangement, it said, is that drug applications are kept confidential, denying the public a chance to comment. Such secrecy, the report said, could undermine public confidence in the regulatory system.
Many of these concerns have been voiced in the past by opponents of genetically modified food and by the National Research Council in a report issued last year. Dr. Stephen Sundlof, director of the Center for Veterinary Medicine at the F.D.A., said the agency believed its regulations were adequate.
''We've required environmental assessments on animal drugs as long as I can remember and they are substantial,'' Dr. Sundlof said. He added that the F.D.A. could also seek input from other agencies, like the Fish and Wildlife Service.
Joseph B. McGonigle, vice president of Aqua Bounty Farms, said the argument by Pew that the F.D.A.'s authority might not withstand a legal challenge was a ''debating exercise'' because no company would mount such a challenge.
''In the real world,'' Mr. McGonigle said, ''I don't see a commercial company benefiting in any way from challenging the F.D.A. and taking on the publicity damage with their customers.''
He also said that the company had commissioned Harvard scientists to do an environmental assessment of the company's plans and that it would eventually make that report public.
- 181 Food and Agriculture