Sea lice pesticide experiment stirs controversy

A plan to kill sea lice on farm-raised salmon with a pesticide that subsequently will be flushed into several bays in southwest New Brunswick is generating concern among fishermen and environmentalists.

The New Brunswick Department of Agriculture and Aquaculture secured an emergency authorization from Health Canada to conduct an experimental "bathing" of about two million market-ready farmed salmon with an insecticide solution in three bays near Blacks Harbour, starting in July. The provincial government and the aquaculture industry are counting on the Bay of Fundy's strong tides to disperse the chemical rapidly to low concentrations so that it will not harm lobsters or other marine life.

"Right now there is no emergency, no big infestation," says New Brunswick's chief aquaculture veterinarian, Dr. Michael Beattie. "We have seen indications in a few cage sites that our present way of controlling sea lice is not working as effectively as it should be. With this experiment we're trying to address the sea lice problem proactively, before we're faced with a major infestation."

Currently salmon farms in Atlantic Canada and Maine control sea lice by feeding affected salmon a medicated feed that contains a pesticide called emamectin benzoate or EB, marketed as "Slice". Slice is toxic to crustaceans, bivalves and other animals native to Maine and New Brunswick waters. But their exposure to Slice from salmon farms is indirect, a result of Slice residues that are excreted in salmon feces.

Dr. Beattie says New Brunswick fish farmers "need access to a variety of tools" for controlling sea lice. "We need to be able to rotate the products we use in order to assure that sea lice don't develop resistance to any of them. We'll definitely be seeking permission to test and use additional products for controlling sea lice in the future."

The research New Brunswick is doing this summer is designed to test the safety and effectiveness of deltamethrin, a synthetic pyrethroid insecticide that is registered for use on some livestock and field crops in the U.S. and Canada. Although deltamethrin has been used to treat sea lice on farmed fish in Norway, Chile, the United Kingdom and Australia, the chemical is not registered for use in salmon farming or for any other aquatic use in Canada or the U.S.

The $700,000 research project is being funded by the Canadian and New Brunswick governments, the New Brunswick Salmon Growers Association and PharmaQ, the Norwegian manufacturer of deltamethrin.

Marketed as AlphaMax, deltamethrin concentrate is highly toxic to crustaceans, including lobsters, shrimp and crabs, amphibians, fish and plankton. The dilute solution of deltamethrin that will be used in New Brunswick's experiment is expected to be harmless to the market-ready salmon that will be treated. Veterinarian Beattie says the fish can be harvested, processed for market and will be safe for human consumption within just a few days after they are treated with deltamethrin.

In 1996 an illegal "experiment" to control sea lice was carried out by some New Brunswick salmon farmers who treated fish with cypermethrin, an insecticide that is chemically very similar to deltamethrin. Cypermethrin released during that experiment killed 60,000 lobsters in a Back Bay holding pound. A civil court case resulting from this illegal pesticide application was settled out of court.

Back Bay is one of the three New Brunswick bays where farmed salmon will be treated with deltamethrin in July and August. The other two are Bliss Harbour and Lime Kiln Bay.

Fishermen, environmentalists raise concerns

Controversy about deltamethrin and the way the fish will be dosed with it in this summer's experiment heated up shortly after World Oceans Day, June 8, the day that Cooke Aquaculture, which owns the most of the cage sites that will be treated with the insecticide, announced that it has received "Certified Quality Salmon Eco-Certification" from Seafood Trust for the salmon that its True North marketing division sells in Canada under the Heritage Salmon brand. Seafood Trust uses International Food Quality Certification (IFQC) standards to assess companies that apply for its certification.

Environmentalists, consumers and fishermen have raised questions about how Cooke's salmon can meet IFQC's key standard, which requires "maintenance of a pristine quality marine environment," if its salmon and the bays in which they are raised are dosed with deltamethrin. New Brunswick environmental columnist Janice Harvey says her efforts to review the specifics of IFQC's standards for its Certified Quality Salmon eco-label have met with resistance and a claim by IFQQ that its standards are proprietary information that cannot be shared with the public.

Dale Mitchell of Deer Island fishes lobster and scallops, operates herring weirs and serves on the board of directors of the Fundy North Fisherman's Association as well as that of the Fundy Weir Fishermen Association. "A lot of us who fish," Mitchell says, "just don't think the aquaculture industry should be using these chemicals in the water where we're fishing. We don't necessarily believe they're safe, and even if they are, we don't think the aquaculture people can be trusted to use them safely."

Reid Brown of Deer Island, who also serves on the Fundy Weir Fishermen Association board, says he is "very concerned about this experiment. We can't understand why they have to do this in so many cages. Well, we do, really C it's because they have the lice getting out of control in those cages, but they don't want people to know too much about that."

Brown recalls that "when all those lobsters got killed back in '96 the scallops died, too. Way into the next year all we got was empty shells. People tried all sorts of things for the lice back then. I was involved in a legal experiment where we tarped off a cage and put in hydrogen peroxide. It killed the larger sea lice but not the young ones. And when we poured it in the cage the fish just thrashed and danced around like they were going crazy. You hear all this about how the province is going green, but putting toxic chemicals in the water doesn't seem to me like a green thing to do."

Dr. Vladimir Zitko, a chemist and former head of toxicology at the Fisheries and Oceans Canada biological station in St. Andrews, now retired, is concerned about the planned release of deltamethrin into marine waters. "Deltamethrin is a very toxic insecticide," Zitko says, "very similar to cypermethrin, the chemical that killed the lobsters in Back Bay in 1996. It's extremely toxic to aquatic animals, and I'd be very hesitant to use it this way in the ocean. It's strongly acid, and I think it should at least be treated with something alkaline to help neutralize it and then disposed of in a toxic waste facility."

David Coon directs the Fundy Baykeeper's parent organization, the Conservation Council of New Brunswick (CCNB). The province-wide environmental organization is asking for reductions in the number of salmon kept in each cage and also in the number and density of salmon aquaculture sites.

Eventually CCNB would like to see all finfish aquaculture operations moved out of marine waters and into secure containment tanks on land or specially designed and fish farm "tanker" vessels. Coon notes that in Ireland's aquaculture industry bath pesticide treatments are administered in tanks on board special fish tankers. Coon believes this approach "would make it somewhat safer to deal with the leftover pesticides." But he emphasizes that "as long as aquaculture cages are located in marine waters, the most effective thing we can do to reduce the risks of pest infestations and disease would be reducing density by limiting the number of cages and cage sites, separating them by greater distances, and reducing the number of fish held in each cage."

Dr. Fred Whoriskey, vice president for research and environment at the Atlantic Salmon Federation (ASF), headquartered in St. Andrews, says his organization's research tends to support David Coon's opinion. Whoriskey points out that "wild salmon in our region have very low levels of infestation with sea lice. Salmon entering the Magaguadavic River, which is near the bays where they will be using this pesticide, are examined every year, and it's unusual to find a sea louse on those fish. A survey of sea lice populations on salmon taken at sea in the Gulf of Maine near the mouth of Fundy Bay about five years ago examined 330 fish, and only one sea louse was found on all those fish. So this would indicate that if the lice are moving from fish to fish, it's happening within the caged populations, not from wild salmon to caged fish."

But Whoriskey says the ASF is "adamant about sea lice being a potential threat to wild salmon. We know that sea lice populations can build up quickly on salmon farms and spread to wild fish. So we're basically in favor of integrated pest management for sea lice and for developing new ways of controlling them as long as these methods don't threaten wild salmon or their habitat."

Jon Lewis of the Maine Department of Marine Resources, who monitors aquaculture from his base in Boothbay Harbor, says he and his colleagues were aware that New Brunswick was considering the use of deltamethrin but did not know that applications had been scheduled for this summer. Lewis says he thinks that salmon farms in Maine "would welcome" the availability of a new chemical tool that has been thoroughly tested and found to be safe. Lewis thinks that referring to the deltamethrin solution that will be used and disposed of in the three bays as "toxic waste" is inappropriate. "Its actual impacts on marine organisms and ecosystems should be studied and understood before you start characterizing it with a loaded term like 'toxic waste,'" Lewis suggests.

Aquaculture veterinarian Beattie and other officials of New Brunswick's Department of Agriculture and Aquaculture did brief some fishermen, fishing organizations and a representative of the Atlantic Salmon Federation in June about their plans to test deltamethrin and release the pesticide into marine waters after using it. No hearing or public information session was required under federal or provincial law, and none has been held.

Contacted for its point of view on the July sea lice control experiment, the New Brunswick Salmon Growers' Association sent a copy of a background paper on "AlphaMax (deltamethrin) Trials for Sea Lice Control on Salmon Farms" prepared by the New Brunswick Department of Agriculture and Aquaculture.

Philippe Laroche, a media relations officer with Health Canada, says the Pest Management Regulatory Agency (PMRA), a division of Health Canada, gave the New Brunswick Department of Agriculture and Aquaculture emergency approval to use deltamethrin in marine waters for the July sea lice experiment. Laroche says anyone with questions, comments or suggestions about Health Canada's action in issuing this approval can write PMRA at 2250 Riverside Drive, Ottawa, Ontario K1A 0K9 Canada, or phone them at 1-800-267-6315.