Foiling fugitive fish

A leading Canadian fish farming scientist is stirring the scientific waters by arguing that it may be safer to risk introducing exotic salmon into a marine ecosystem than to farm native ones there.

“The biggest environmental danger we face from salmon escapes is when farming species within their native range, such as Atlantic salmon in the Atlantic Ocean,” says Dr. Ian Fleming, Director of the Ocean Sciences Centre at Memorial University of Newfoundland.

He is presenting the results of his latest research on the risks of fugitive farmed fish at the 2005 meeting of the American Association for the Advancement of Science in Washington D.C. on February 18. The work was supported by Science and Engineering Research Canada (NSERC).

Fish raised in large ocean pens have genetic traits that make them distinct from their wild counterparts. This has led critics of the fish farming industry to argue that farmed fish that break free – a common occurrence – might breed with native ones, perhaps compromising the health of the entire species and threatening its ability to survive in its natural setting.

Dr. Fleming says the key to avoiding this real ecological danger is to break what is normally considered a biological taboo: deliberately introducing a new species into an ecosystem. “The real issue is a fascinating one – it’s to analyze if it is actually better to be farming Atlantic salmon on the West Coast rather than farming Pacific salmon there,” says Dr. Fleming. “That might be considered a heretical idea, in the sense that we would be introducing an exotic species into the Pacific, and all our knowledge of invasive species suggests that we shouldn’t do that. But with salmonids, particularly Atlantic salmon, there are indications that that might not be such a bad idea.”

Atlantic and Pacific salmon do not interbreed successfully. If escapees find themselves on the opposite coast, this substantially reduces the likelihood that they will ecologically overwhelm local salmon populations.

With the rapid growth of ocean fish farming along the world’s coastlines, and a general desire to limit the ecological impact of this activity, Dr. Fleming says there’s presently more scientific and public interest in finding solutions, whatever they might be.

“There’s more of a consensus on trying to work toward solutions rather than arguing over whether there is a problem or not,” explains Dr. Fleming. “Making fish farming more sustainable is certainly in everyone’s better interests.”

Dr. Fleming himself is a transplant from the West Coast. He was previously an Associate Professor at the Coastal Marine Experiment Station and Department of Fisheries and Wildlife at Oregon State University, before moving to the Ocean Sciences Centre in the summer of 2004.

His interest in fish farming started 15 years ago when he began doctoral work on fish evolution. “I thought of hatcheries as an experiment that’s being done for me,” says Dr. Fleming, who spent a decade studying such facilities in Norway. That country has the largest salmon farming industry in the world.

The Ocean Sciences Centre at Memorial University of Newfoundland is a key North American venue for fish farming research, with 11 full-time faculty members, along with a similar number of adjunct and cross-appointed professors, and dozens of graduate students