Homer Alaska - Business

Story last updated at 11:16 AM on Wednesday, October 26, 2011

Wild sockeye in B.C. infected with lethal virus

Alarm bells sounded in fishing communities throughout the Pacific Northwest as word got out last week that wild sockeye salmon in a stream in British Columbia were infected with the same disease that wiped out fish farms in Chile.

The virus, called infectious salmon anemia, or ISA, is highly contagious, lethal and known to mutate quickly. In the confined conditions of a fish farm, it can spread quickly and decimate the population.

The disease was found in two juvenile sockeye salmon out of 48 sent in for testing, and the smolt showed the classic skin lesions associated with ISA. They were found in the popular sport fishing area of River's Inlet in British Columbia, about halfway between Washington and Alaska.

This incident is the first time ISA has been detected in wild sockeye stocks, although there have been outbreaks in wild Atlantic salmon stocks.

The Canadian government insists there is no ISA present in the B.C. fish farms, thought to be the source of infection in the wild sockeye. However, there does not need to be an outbreak for the disease to be present, according to a well-researched 2010 article by Kristin Hoelting in Pacific Fishing magazine.

The article states that there are two strains of ISA, one originating on the Atlantic coast of North America, and one in Europe. It was the European strain that caused the massive outbreak in Chile beginning in 2007. That outbreak caused Chilean farmed salmon exports to plummet, and cost 40 percent of farmed salmon workers to lose their jobs. It also was the European strain that was found in the sockeye in British Columbia.

The article also explains that there are two types of transmission: horizontal and vertical.

Horizontal transmission comes from use of infected equipment, or infected live brood stock, passed on through blood or feces, something that is less likely to happen in recent years as salmon farmers increasingly use imported eggs rather than live brood stock.

Vertical transmission comes from ISA being passed from one generation to the next through the eggs, a possibility that research is showing to be highly likely.

Regardless of there never having been an ISA outbreak in B.C., the viability of vertical transmission has led researchers to warn that it is a matter of when, not if, it will happen.

Because of the risk of vertical transmission, the Canadian Food Inspection Agency has implemented regulations that only allow import permits for eggs coming from certified sources, which means they must have been screened for ISA and disinfected in their country of origin prior to import. There is also a one-year quarantine period during which eggs are tested monthly for ISA. Also, eggs are only imported from Iceland, where there has never been an outbreak of ISA.

However, there are two strains of ISA, virulent and avirulent. Avirulent strains are more difficult to detect, are generally asymptomatic and are more likely to be passed on vertically. Screening and detection practices occur only after eggs have been fertilized, meaning the virus could be present inside an embryo as a result of the fertilization process. Once inside the embryo, the virus would be protected from chemical disinfectants.

Because ISA mutates quickly, as it replicates, it could shift from avirulent to virulent in a matter of generations and lead to outbreaks in the B.C. Atlantic salmon farmed fish population, or mutate to infect wild fish.

Genetic testing should be able to determine the source of the infection in the sockeye salmon found with the lesions.

While the Canadian government is downplaying the find, calling the tests for ISA "inconclusive," the Anchorage Daily News is reporting that Sen. Maria Cantwell, D-Wash., and Alaska Sens. Lisa Murkowski and Mark Begich have introduced a bill that calls on an interagency group of scientists to provide Congress a report in six months that details surveillance, susceptibility of species and populations, potential vectors, gaps in knowledge, and recommendations for management.

The Food and Drug Administration has given its approval for genetically modified salmon from AquaBounty to be sold in U.S. stores, passing the issue on to the Office of Management and Budget for further review, in spite of legislation introduced in Congress to halt the process.

The genetically modified fish grow to market size twice as fast as normal farmed salmon due to the splicing in of genes from king salmon and genes from an ocean pout that allows the fish to produce growth hormones year-round, instead of only in the summer as natural salmon do.

If the OMB gives the fish the green light, it will be the first genetically altered animal product approved for human consumption, but consumers will not know that is what they are eating, because the FDA is not requiring it to be labeled as such.

Concerns abound regarding the fish, including the thoroughness of testing, worries about human allergies, and the possibility of escape that could release the fish to mix with wild stocks with unknown consequences.

AquaBounty says its fish are sterile, although even the FDA acknowledges that is not 100 percent true. AquaBounty also states its fish will be raised only in on-shore tanks, preventing possible release into the wild, although since they are planning to sell the eggs to different growers, it is unclear who would be ensuring that.

In the meantime, Food and Water Watch, a national consumer advocacy group, is reporting that AquaBounty has received nearly $3 million in tax-payer funds for more research into genetically modified fish, most recently nearly half a million dollars to refine its fish sterilization techniques.

Cristy Fry has commercial fished out of Homer and King Cove since 1978. She can be reached at realist468@gmail.com.