The deaths of nearly 1,000 lobsters in areas around Deer Island, Grand Manan and Pocologan last November and December are causing fishermen, environmentalists and the media to question whether a pesticide that is toxic to lobsters was used illegally by fish farmers in New Brunswick. However, the investigating agency has not confirmed that the pesticide cypermethrin was the cause of the deaths, although it was detected on some lobsters, and aquaculture organizations say that fish farmers would not have used the chemical in Canadian waters.

Cypermethrin, which is toxic to lobsters, has been used legally, under strict regulations, this past fall at salmon farms in Cobscook Bay in Maine to treat for sea lice, but representatives of the aquaculture industry say the chances of the pesticide used in Maine causing the lobster deaths in New Brunswick are virtually nil.

Environment Canada was first informed on November 19 that lobster fishermen in southwestern New Brunswick were finding dead and dying lobsters in their traps, according to Brigitte Lemay, media relations advisor for Environment Canada. The lobsters were found on that date in traps hauled by fishermen out of Seal Cove, Grand Manan, but not a large number of lobsters were affected, according to Harvey Millar, area director for Southwest New Brunswick, Department of Fisheries and Oceans. On November 24, about 40 dead lobsters were found near Pocologan, and then on December 3 around 700 lobsters that were stored in crates near a wharf at Fairhaven, Deer Island, were found to be dead or dying. Millar says that the number of lobsters is very small, compared to the number that are caught following the opening of the season on November 10. The area spans some 50 kilometres. Environment Canada collected samples of the affected lobsters as well as fish, mussels and kelp near those areas. Those samples were analyzed at Environment Canada's lab in Moncton.

On December 22 Environment Canada opened an investigation on the cause of the dead lobsters near Grand Manan and opened another investigation on February 10 into the lobster kill near Deer Island. "Environment Canada's objective through our investigations is not to determine if a substance is responsible for the death of lobsters and other fish; it is to determine if there was a release of deleterious substances, such as cypermethrin, into waters frequented by fish," Lemay states in an e-mail. She adds, "Currently, it is premature to draw any conclusions related to the cause of the dead lobsters. The investigation is still under way, and evidence is being gathered. As such, we cannot provide any certainty as to the end date for the completion of the investigation." According to Millar, cypermethrin was detected on lobsters from the samples collected at Seal Cove and Deer Island.

Violations under the Fisheries Act, which prohibits the deposit of substances deleterious to fish, including cypermethrin, into fish-bearing waters, carry fines and penalties of up to $300,000 for a summary conviction offence or up to $1 million for an indictable offence.

Pamela Parker, executive director of the New Brunswick Salmon Growers Association, says Environment Canada has told the association that trace amounts of cypermethrin were detected in the samples that were collected but the agency has not stated, at least at present, that the lobster deaths were caused by the chemical.

Parker says fish farmers in Canada do not use cypermethrin, as it is not licensed for use in the country. Until last year, only one product, Slice, was licensed in Canada for use to treat sea lice. Now four therapeutants are approved C AlphaMax and Salmosan, which involve bath treatments, and Slice and Calicide, which are drugs placed in the feed. Although sea lice levels on salmon are presently higher than normal in some areas, because of the warmer winter, she says the levels are not unmanageable. Parker does not think any fish farmer would be tempted to use cypermethrin illegally, since there are four other products available. The industry uses an integrated pest management approach that includes other measures to control sea lice besides the four chemical products.

Parker comments, "New Brunswick salmon farmers are just as interested in what's happening in the lobster industry as lobstermen are." She says fish farmers, like fishermen, want to ensure that the marine environment is healthy.

Lobster fishermen and environmental groups, though, have had concerns about possible illegal pesticide use to control sea lice since cypermethrin was used in 1996 and ended up killing about 50,000 lobsters in a Back Bay holding pound.

Cypermethrin use in Maine

While the use of cypermethrin in aquaculture cages is prohibited in Canada, the pesticide's use is allowed under certain restrictions at salmon farms in Maine. Under the U.S. Food and Drug Administration's (FDA) Investigational New Animal Drug (INAD) program, the use of Excis, a trade name for cypermethrin, was allowed during the late 1990s for sea lice treatment at salmon cages in the state. Approval was again granted for a period from November 2009 to January 2010 for Cooke Aquaculture to use Excis for treatments at six salmon sites, all in Cobscook Bay, according to Matthew Young of the Maine Department of Environmental Protection's (DEP) Division of Water Quality Management. In addition to conditions placed by the FDA to use cypermethrin, the DEP issues restrictions on the pesticide's use under the Maine Pollutant Discharge Elimination System Permit for salmon aquaculture.

Cypermethrin is used in a bath treatment in which a tarp is pulled up inside the cage, and a very low concentration of the pesticide is put in the water inside containing the salmon. The water is not released outside the tarp for at least an hour, and the concentration decreases over time as cypermethrin binds with organic compounds in the water. Young says that fish farmers have also used cypermethrin in well-boats that are used to transport salmon, and the water is released into Cobscook Bay, near the farm sites.

With the drug usage, the FDA requires environmental monitoring of the water, sediments and any organisms in the environment, and the results must be provided to the DEP. The survey results following the treatments in Cobscook Bay show that cypermethrin is at non-detectable levels in the waters or in any of the nearby environment where samples were collected.

Chances are 'virtually nil'

Since the water test sampling results of cypermethrin use at Maine cage sites all show that the chemical is at non-detectable levels, Sebastian Belle, executive director of the Maine Aquaculture Association, believes the chances that a plume from Maine caused the lobster deaths near Grand Manan and Deer Island are "virtually nil. I can't see that ever happening." He says the chances are the same for the chemical having come from a well-boat that used cypermethrin, since they discharge the water near the cages in Cobscook Bay. Belle also says that the chances of cypermethrin causing lobsters to die if it was used illegally in New Brunswick but under the same standards as required in Maine are "virtually nil. We can't detect any residue at all around the cages."

Belle points out that fish farmers have "a very limited suite of chemicals" that are approved for use in the industry, with only five fully approved in the U.S. One of those five is salt. Hundreds of chemicals, though, are approved for use in agriculture and at least a hundred for organic agriculture, he says. The cost of getting a new chemical licensed for use can run up to $15 to $20 million, and fish farmers would much rather use non-chemical means for controlling diseases and parasites. The development of a range of vaccines has "hugely reduced" the use of antibiotics in the industry, he says, and the approaches of bay management, crop rotation and site fallowing have also helped. Antibiotics have not been used in the industry in Maine for the past five years.

The only way fish farmers can use any chemical response to sea lice is through the FDA's INAD program, which is a precursor to the full licensing application. Through an integrated pest management program, the industry has gone from barely controlling the sea lice problem to having virtually no sea lice issues. Slice has been used in the industry since 2000, but Belle notes that, with only one chemical control method, the risk of sea lice developing resistance to the therapeutant increases. The industry then sought to have cypermethrin approved again for use, as the sea lice exceeded a certain threshold this year. Presently no drug is allowed for sea lice treatment in 2010 in Maine, although two are on the docket for approval: Excis and Slice.

The INAD program is a highly controlled system, Belle says, with restrictions by the FDA, which is concerned with the efficacy of the chemical, the U.S. Department of Agriculture, which is concerned with animal health, and the Environmental Protection Agency, which checks on the environmental impact. He notes that cypermethrin is fully permitted for use in salmon farms in Europe, and it's sold over the counter for agricultural uses in the U.S., marketed under the trade name Ripcord. Ripcord is not used in the salmon industry. The standards for cypermethrin's use in the aquaculture industry in Maine are much higher than for its use in the U.S. agricultural industry or the aquaculture industry in Europe, according to Belle.