Grand Manan fish farmers have been fighting an outbreak of the deadly infectious salmon anemia (ISA) that struck the northern part of the island earlier this year and now is hitting sites around White Head Island. Approximately 15 cages of fish have been removed at about six salmon farms, with four or five companies affected, according to Michael Beattie, the provincial veterinarian with the Department of Agriculture, Fisheries and Aquaculture (DAFA). The province has issued eradication orders for any cages in which two or more fish test positive for ISA by two different tests. Beattie notes that it's been four years since an ISA outbreak has occurred on the island.

     The disease cropped up around Grand Manan at a site by Ross Island this past winter, and after affecting fish farms around the upper part of the island that had market-sized salmon, the disease spread to southern Grand Manan and the White Head Island area, where the fish are still a year from becoming market sized. Nell Halse, director of communications for Cooke Aquaculture, says the company has removed all of its market-sized fish at affected farms in the northern part of the island, and cages are being eradicated as needed in the southern part. Sites in the northern half of the island will now lie fallow until next spring. "The issue now is the lower part of the island. We're trying to manage it aggressively," she says. "The cages are coming out as fast as they can when the tests say so." She adds that Cooke Aquaculture hopes that all of the companies are aggressively cleaning out any cages in which fish have tested positive for the disease.

     Fish that are close to market-sized are sold, since ISA poses no risk to human health and almost all of the fish in cages in which ISA has been detected do not have the disease. Halse notes that the loss of fish is a significant cost to the company, and that cost "is carried on the shoulders of the industry." There is presently no compensation program in Canada, and in Maine the aquaculture industry is lobbying for the renewal of federal funding for ISA losses.

Managing the disease
     Among the steps the province is taking to curb the disease is the adoption of a three-bay management system, with three different areas being on separate cycles for stocking over a three-year period, so that there is a four-month fallow period for each site. Halse notes that the three-bay system also should help eliminate the disease because there will be no vessel traffic from one year-class area to another.

     In addition, all harvest vessels have to pass an audit that checks disinfection procedures, with three additional unannounced audits each year. Vessels cannot lose more than a litre of bloodwater overboard, so that there is 99.9% containment of water within the vessel, according to Beattie.

     Halse says that Cooke Aquaculture had asked scientists to study all of the options for dealing with the disease, and they agreed that eradicating cages quickly is "the only way to go."

     Concerning the development of a vaccine for ISA, Beattie notes that the virus has mutated 14 times in the last year and a half. None of the vaccines are working now, because of the rapid mutation of the virus, which Beattie says is like the influenza virus in humans.
Although the management of ISA currently falls under the provincial government's regulations, the federal Canadian Food Inspection Agency will become the lead agency, along with the Department of Fisheries and Oceans, in administering a National Aquatic Animal Health Program. The new program is designed to meet international aquatic animal health management standards to protect Canadian wild and farmed resources from serious infectious diseases such as ISA. Beattie notes that there then should be more federal assistance to help manage the disease.

     Although Glenn Cooke, CEO of Cooke Aquaculture, issued a challenge, at a farmed fish health management workshop last April, for the salmon farming industry and fish health researchers to work on eliminating ISA, Beattie says that it is very difficult to eradicate any disease that's in the water, because there are so many reservoirs of the disease. The best strategy, he says, is to try to manage the disease. Noting that wild herring carry ISA, the provincial veterinarian points out that aquaculture processing plants have to meet a higher standard concerning the release of any effluent than processing plants for wild fish. "If companies are bringing in fish with the disease, it will spread to the coastal waters," he says. The treatment of effluent from wild fish processing plants will have to be addressed, he believes.

     The provincial Department of Agriculture, Fisheries and Aquaculture works with the U.S. Department of Agriculture and the Maine Department of Marine Resources so that the two countries' regulations are harmonized for managing ISA. All vessels leaving Canada from an ISA-positive site to a negative site in the U.S. have to follow a strict disinfection protocol, including hauling the vessel out of the water and pressure-washing it, to try to avoid the spread of the disease. All of the fish in Cobscook Bay in Maine had been removed in 2001 in an effort to control a serious outbreak of ISA. Samantha Horn Olsen, the DMR aquaculture coordinator, says the USDA and DMR consult with the aquaculture companies and the provincial DAFA about vessels that are crossing over to sites in Maine, with a vessel permit required. "We make requirements to minimize the risks to the greatest degree possible," she says.