The Facts about Atlantic Salmon: Aquaculture

The Facts about Atlantic Salmon: Aquaculture

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1/9/2000 --  -- 

The Maine Conservation Plan fails to adequately address the threats posed to wild salmon stocks by the aquaculture industry. The lack of progress being made on addressing these threats, outlined below, has been cited by the United States Fish and Wildlife Service, the National Marine Fisheries Service, and the conservation community as a reason wild Atlantic salmon need protection under the Endangered Species Act.

PROBLEM 1: Aquaculture Hatcheries Located in Wild Salmon Rivers

Fact: In New Brunswick's Magaguadavic River, the only river in North America being studied to determine the interactions of farmed and wild fish, 82 percent of sampled salmon smolts leaving the river in 1998 were determined to be aquaculture-origin salmon which had "leaked" from the three aquaculture hatcheries located in the river system. The run of wild salmon returning to this river has declined from an average run of 800 fish fifteen years ago to just 31 fish in 1998.

Fact: In 1999, over 20% of salmon smolts leaving the Pleasant River to go to sea were of aquaculture origin.

PROBLEM 2: Aquaculture Escapees Getting into Wild Rivers

Fact: Approximately 5 million Atlantic salmon are being raised in sea cages off the coast of Maine. Even if aquaculture firms prevent 99.99 percent of their salmon from escaping, the one hundredth of one percent which do escape (400 salmon) still exceeds the total number of wild salmon returning to Maine's seven Downeast Rivers in recent years (under 100 salmon).

Fact: The number of salmon escaping from Maine aquaculture sea cages each year is unknown because the State of Maine does not require aquaculture firms to document and report how many salmon escape from their sea cages. The reporting of escapees is required in other countries.

Fact: Salmon of farmed origin were first documented in a Maine river in 1990. Since that time, escapees have been documented in eight rivers, including ripe females.

Fact: In 2000, 27 of the 28 fish which returned to the Denny's River to spawn were aquaculture escapees (Maine Atlantic Salmon Commission Data). In all rivers with counting facilities near the fish farms in Washington and Hancock Counties are combined, 51 wild fish and 60 aquaculture escapees returned this year.

Fact: Though detailed reports of escapees are not available, isolated incidents have been documented including 20,000 escapees in southwestern New Brunswick during a storm in 1994, 8,000 escapees from cages in Annapolis Basin, Nova Scotia in 1998 and 50,000 fish from the Bay of Fundy in 1999 and an annual loss of 60,000 escapees in the Pacific Northwest.

Wild salmon are highly adapted to their natal rivers. The continued introduction of farmed salmon into a river can have irreversible genetic consequences and will likely lead to the extinction of the wild run.

PROBLEM 3: Industry Use of Non-Native Strains of Salmon

In the recent years between 20 and 50 percent of the genetic material used in Maine's aquaculture industry originated from European strains. Canada ascribes to international protocols established by the North American Salmon Conservation Organization (NASCO) and does not use European strains as broodstock in the aquaculture industry. Although the United States is a signatory to these international protocols, the State of Maine contravenes them by allowing the use of foreign strains as aquaculture broodstock.

Fact: The State of Maine and the Conservation Plan continue to allow its aquaculture firms to defy the international agreements barring the use of non-native strains.

Fact: The State of Maine and the Conservation Plan has continued to allow the aquaculture industry's use of European strains despite the advice of virtually all fishery scientists, the federal agencies and the conservation community.

Fact: Some Maine salmon growers do not use European strains of salmon, despite industry claims that use of such fish is necessary for them to be competitive.

Genetic alteration, swamping and dilution will ultimately lead to the loss of wild salmon. When a domesticated aquaculture salmon enters a river and breeds with a wild salmon, the hybrid offspring can lose much of the wild instincts they need to survive since once of their parents lacks them. Hybrid individuals will be adapted on average to conditions intermediate to the wild and farm environments, with reduces average survival, and reproductive success and lower return of spawners, compared to non-hybrid fish.

PROBLEM 4: Diseases Continue to Plague Aquaculture Industry

Fact: In Norway, smolts imported from the Baltic with the parasite, gyrodactylus salaris, have led to the rotenoning of 20 wild salmon rivers to eradicate the disease.

Fact: In Ireland and on the west coast Scotland, there has been a virtual collapse of sea trout, a species closely related to Atlantic salmon. This has been associated with massive infestations of sea lice in estuaries where there are salmon farms. A recent study in Scotland concluded that sea lice are killing 90% of the wild salmon smolt as they emigrate from the rivers.

Fact.: Just over the border in the Bay of Fundy, the Atlantic Salmon Federation has proven farmed escapees are entering the Magaguadavic River infected with the fatal virus, Infectious Salmon Anemia. At the same time, wild Atlantic salmon were documented, as they entered the Magaguadavic River, to have the ISA disease.

The environmental costs must be weighed against the economic gain of the aquaculture industry. In Scotland, the government has recently declared a moratorium on aquaculture development along much of its coast. In part this is related to ISA outbreaks in salmon farms for the first time. As well, questions have arisen in Scotland concerning feces and waste from aquaculture operations leading to plankton blooms that closed down much of the scallop harvesting industry this past year. What other marine species that Maine depends on could be affected as this industry continues to grow?

Date: 1/9/2000