Infectious Salmon Anemia

Disease in Atlantic salmon caused by a virus, spread easily in crowded fish farm conditions in both Pacific coast and Atlantic coast farms.

How to tell if your salmon has ISA:

1. Your salmon may be lethargic.
2. Check your salmon for interior lesions, including hemorrhaging on the kidney and other organs.
3. Does your salmon have swollen eyes?
4. Fluid in the body cavity?
5. Pale gills?
6. Swollen kidneys or spleen?
7. Check for darkening of the posterior gut.

How did your salmon contract ISA?
Your fish probably came in contact with an infected fish; or in contact with mucus, blood, viscera, trimmings, muscle, or feces of an infected fish; or in contact with equipment contaminated with parts from an infected fish; or contact with people who handled infected fish, fish parts, contaminated equipment or were on, in, or around ISA affected sites. The virus doesn't cause disease in people, but they can carry it.
So can sea run brown trout and rainbow trout.
And so can sea lice.

Oh, and if your farm is within 5 km from an infected farm or processing plant handling infected fish without adequate waste treatment, your salmon are at a 5-13 times higher risk of getting ISA.

ISA first gained attention when it swept through the Norwegian fish farming industry in 1984, which set up quarantine zones. Scotland and the Shetland islands caught it next, and implemented a compulsory slaughter regime for infected farms, followed by a fallow period. In 1996, it hit Canada's Atlantic fisheries. In 1998, the Canadian government paid New Brunswick fish farmers more than $6 million to kill one-third of the province’s total production in an effort to stop the spread of the virus. That didn't work. Next, Canadian aquaculturists in New Brunswick began vaccinating smolts with an autogenous vaccine in the winter of 1998, and have chosen to vaccinate the fish in their 1999 year class smolts. That didn't eradicate it either, and every Canadian farm tests their fish now. US salmon farms in Cobscook Bay are close enough to fall within the ISA virus positive "quarantine zones" in New Brunswick waters, the question of when ISA reaches Maine is not "if" or "how" but "when."

And one more thing: In October 1999, it was confirmed that infected salmon had escaped and spread the disease to wild populations. Next to genetic dilution, disease poses the greatest threat to the survival of wild Atlantic salmon.

This is the kind of stuff that happens on a farm. It's about eradicating and killing off animals, and the losses are devastating.

So says Nelle Halse, not a spokesperson for landfarming, but for the New Brunswick Salmon Growers Association, a group of sea-farmers. She is describing infectious salmon anemia (ISA), what has come to be called the foot and mouth disease of the sea.

It is a member of the influenza family, a virus not harmful to humans, but in salmon causes internal bleeding and destroys organs. Infections in fish farming operations began in Norway 17 years ago, then Scotland. Now, it has spread to Nova Scotia, New Brunswick, and Maine.

As with foot and mouth, the farmers' reaction is to kill: in the Bay of Fundy, Nova Scotia, 4.5 million salmon, at a cost of $70 million have been killed in an attempt to control the outbreak.

It's really a disease that has to be managed; it may never go away, says Halse. So, we resign ourselves to another cost of doing business. We won't see the pyres that we now associate with the British countryside in the wake of the outbreak on land, but is there another consequence.

If this were only a disease of, and in, factory-farming, maybe we could be afford to be complaisant--it is a business after all, and there are risks. So, what's the problem?

Fred Whoriskey is vice-president of research for the Atlantic Salmon Federation, a wild-salmon conservation group based in St. Andrews, New Brunswick and has been working to restock the Magaguadavic River in southern New Brunswick. He has detected ISA in escaped farm fish and the wild stock he collected to restock the river. Not killing the wild fish immediately, he bred them to see if the virus was "vertically transmitted" to their offspring; it is.

As usual, the science has been challenged: the result could only be a false positive--or it could be correct.

ISA has also been detected in wild fish in Scotland and the Shetland Islands, Chile, and the Faroe Islands near Denmark.

However, in both Canada and the United States, wild salmon are endangered species. The salmon in eight Maine rivers have been added to the federal endangered species list.

Farm fish regularly escape. 100,000 fish escaped last December from a site in Machais Bay in Maine during a storm. The outbreak in Maine is in Cobscook Bay; the Dennys river, one of those whose species were added to the endangered list, flows into Cobscook Bay. And where natural stocks are depleted, cultivated stocks can infect, or even replace them.

This is the problem, as environmentalists have always, Cassandra-like, pointed out.

Today, the crisis has only been caused by two elements:

1. the outbreak of disease that factory-farming invariably cultivates,
2. the inevitable escape of farm stock, and its interaction with dwindling wild species.

In the almost present, when genetically modified fish are factory-farmed, who will accept the assurances of their advocates that there is no risk?

---

Reference: http://www.ottawacitizen.com/national/010416/5015193.html