Canadian Farmed Salmon May Contain Delousing Chemical

VICTORIA, British Columbia, Canada, December 14, 2004 (ENS) - Residues of a chemical used to control sea lice in Canadian farmed salmon appeared in salmon headed for market in 2000, but instead of cleaning up the food supply, the Canadian government lowered its standards, a Canadian environmental group warned in a new report.

American salmon lovers may possibly be consuming the chemical along with their fish, cautions the Raincoast Conservation Society, pointing out that Canada exports the majority of its farmed salmon, 95 percent of it to the United States.

The Raincoast Conservation Society, a non-profit research and public education organization, released a report last week showing that Canada’s Ministry of Health approves the widespread use of an emergency drug called Slice to control sea lice Canadian aquaculture pens.

Emamectin benzoate is the active ingredient in Slice, which is fed to fish as a pre-mix coated on feed.

Salmon aquaculture operation in southeast New Brunswick (Photo courtesy DFO)

"…we are consistently finding drug residues," wrote Glenn McGregor of the CFIA in December 2000 to Gerard Lambert of Health Canada’s Human Safety Division, adding that, "We are prepared to sample and detain each shipment if necessary, but this will disrupt the orderly marketing of the product."

At that time, CFIA had zero tolerance for Slice consumption.

"Rather than notify the public and issue a recall, Health Canada decided to change its policy and accept Slice residues in farmed salmon up to a maximum of 50 parts per billion," Raincoast writes.

"Canada’s loopholes are putting U.S. consumers at risk," said Sophika Kostyniuk, San Francisco based markets campaigner for the Coastal Alliance for Aquaculture Reform, a coalition of environmental groups fighting destructive fish farming practices.

"This should be a wake up call not only to U.S. and Canadian Health authorities, but to the thousands of people who have unknowingly consumed farmed salmon treated with this drug," Kostyniuk said.

Raincoast called emamectin benzoate "a neurotoxin listed by the U.S. Environmental Protection Agency (EPA) as highly toxic," but although the U.S. agency controls the use of this chemical, the EPA website does not list emamectin as "highly toxic."

In fact, in a 1999 annual report on pesticides, the EPA listed emamectin benzoate as "safer" than others on the market because it presents either a "low risk to human health; low toxicity to non-target organisms (birds, fish and plants); low ground water contamination potential; low use rates; low pest resistance potential," is compatible with integrated pest management, or is a biopesticide.

Still, the Raincoast Conservation Society is alarmed at the rate of use of Slice in Canadian fish farms. "Documents we obtained revealed over 170 million farmed salmon have been given Slice in the last five years - over 35 million in 2003 alone," said Theresa Rothenbush, aquaculture specialist for the Raincoast Conservation Society which commissioned the report, "Diminishing Returns: An Investigation Into the Five Multinational Corporations That Control British Columbia’s Salmon Farming Industry."

Salmon in a net cage on a British Columbia fish farm (Photo courtesy BCSFA)

"Currently," CFIA said, "there is an extensive therapeutant monitoring program in place, including the comprehensive testing of 11 farmed finfish species raised in Canada over a broad range of therapeutant residues, including florphenicol amine and emamectin benzoate."

In the United States emamectin benzoate is approved by the U.S. Environmental Protection Agency (EPA) on a year to year emergency basis only. It is generally used on cotton for control of beet armyworm and tobacco budworm. The EPA sets strict limits on the residues that may remain on cottonseed products and in the meat of animals fed on those products.

The use of Slice in farmed salmon is a concern to some U.S. scientists. "We should not have to consume these chemicals in our salmon," said Dr. David Carpenter, a professor at the Environmental Health and Toxicology Division, School of Public Health at the University of Albany in New York.

Carpenter is currently a member of the editorial board of the "Journal of Public Health Management and Practice" and the "International Journal of Occupational Medicine and Environmental Health." He is the host of a 30 minute public health information show called "The Public Radio Health Show," which is carried on more than 170 stations nationwide.

"Emamectin is one of a class of drugs known to block a major inhibitory neural transmitter in the brain," Carpenter said. "Animal studies have demonstrated exposure to this chemical during development causes changes in behavior and growth as well as pathological changes in the brain."

New research suggests that Slice is a causes lobsters to molt prematurely. The scientist who conducted this study, Dr. Les Burridge, editor of the Proceedings of the 6th international sea lice conference held earlier this year, writes, "Chemicals used to control infestations of sea lice on cultured salmon have a potential for impacting non-target organisms, particularly other crustacea. Investigations have been conducted on lethal impacts but observations made during these experiments indicate potential for ecologically important sub-lethal impacts."

Despite the extensive use of Slice and other medications on B.C. salmon farms, Raincoast objects that "only an extremely small percentage of fish are tested for drug residues. Each year, approximately 500 salmon are tested for Slice residues across Canada."

Aquaculture, which now produces 30 percent of the world's seafood, is an important industry in coastal British Columbia. Farmed salmon is B.C.'s largest agricultural export product.

But disease, including sea lice, is a big problem for the B.C. industry. Sea lice affect wild and farmed fish. In British Columbia, lice from wild salmon returning from the ocean to spawn can result in an increase in the levels of lice on fish farms in the fall and early winter. It is to treat these lice that Slice is used.

Just a few companies are responsible for most fish farms in the province. Fifteen years ago, there were 50 fish farm companies in British Columbia. Today, there are 12, and just five multinationals operate 80 percent of B.C.’s salmon farm sites as well as scores of salmon farms around the world.

Salmon is a favorite food of many Americans. (Photo credit unknown)

Those losses are the reason why so much Slice is used on farmed fish, Raincoast says.

The organization is calling for "an immediate moratorium on all open net cage salmon farm expansion in B.C," but it is not the only one. The Western Canada Wilderness Committee and the David Suzuki Foundation are among a host of environmental organizations lobbying for an end to the open net cage aquaculture system.

"We urge government and industry to support and promote closed-tank solutions, so as to stop the harmful spread of disease and protect valuable wild species and the environment," Raincoast writes. "There must also be stiffer fines for regulatory offenses, full disclosure of the use of medication on salmon farms, and an immediate investigation into the extensive use of the sea lice emergency drug Slice – a medication suspected of having significant impacts on wild species."

The federal Department of Fisheries and Oceans is responsible for wild salmon, while the province has jurisdiction over salmon farms.

B.C. Minister of Agriculture, Food and Fisheries John van Dongen did not comment on the Raincoast report.

See the Raincoast report, "Diminishing Returns," online at: http://www.raincoast.org/aquaculture/index.htm