Infectious Salmon Anemia (ISA) has once again reared its unwelcome head in Cobscook Bay.

On June 12, the Maine Department of Marine Resources (DMR) ordered the destruction of 28,000 farmed salmon in a Heritage Salmon pen located in Eastport’s Broad Cove. According to DMR Aquaculture Coordinator Andrew Fisk, the order was based on the discovery of a confirmed case of the virus that causes ISA. The market-sized fish had been placed in the pen in May 2002.

Fisk adds that no other cages at this site, or other salmon farms have tested positive for the virus.

Heritage Salmon officials, however, remain optimistic about the future of the Cobscook Bay operation.

“These fish were scheduled to be harvested in July, so what this means, unfortunately, is that we’re a month ahead of schedule,” says Bill Robertson, Heritage director of operations, in Saint John, New Brunswick. “This was not entirely unexpected. On the New Brunswick side we’ve learned that ISA will recur from time to time, but in a weakened state. This in fact is what happened, and it is not an insurmountable obstacle. We expect to continue operations just as before.”

The case was reported according to the requirements of the DMR’s rules, according to Fisk. However, the cause of the outbreak at the Heritage farm was not immediately known.

He added that Heritage “is in compliance with all DMR regulatory requirements and has worked extensively with USDA staff located in Eastport in the review of biosecurity procedures and fish health surveillance.”

As for the future, Fisk says, “We are increasing surveillance per the requirements of the USDA program. This increased surveillance will be implemented under auspices of USDA and its technical committee.”

In a prepared statement, DMR Commissioner George Lapointe said, “I have issued an eradication order according to the authority of the Department’s fish health rules that requires the harvest of these fish be conducted under the supervision of DMR and USDA fish health professionals and according to stringent biosecurity provisions.”

Fisk says that this is the first confirmed case of the virus that causes ISA in Maine since all fish in Cobscook Bay were destroyed in January 2002, following nine months of outbreaks in the prior year. Since fish were restocked in Cobscook Bay in May of 2002, all salmon farms throughout the State have been subject to the disease control program requirements of the USDA and the DMR.

He adds that the control program outlines mandatory routine surveillance for disease, routine biosecurity audits, vessel movement restrictions and a coordinated program of sea lice treatment. Sea lice are one of the suspected vectors or contributing sources to ISA outbreaks. Monitoring results from the sea lice control effort, which is coordinated by the University of Maine Cooperative Extension program, show that lice counts in Cobscook Bay are at low absolute numbers, and at their lowest level in the last four years.

Lapointe said, “We are obviously disappointed that ISA has been detected in Maine, given the amount of work by farmers and the state and federal government to try and control this disease, but it should be noted that the control program is just that – control. We should expect that we will see additional, but hopefully limited outbreaks, until some form of definitive control for this disease is developed.”

He added, “We know that the virus can survive in the water column for up to several days and the tidal circulation in the Passamaquoddy area moves a lot of water a great distance in a short time. So all the governments involved know that we have to have coordinated programs that act aggressively and thoroughly to control outbreaks. I am more comfortable now that we have comparable programs on both sides of the border.”

Infectious salmon anemia is a fatal viral disease that affects the internal organs of Atlantic salmon. The disease cannot be contracted by humans and does not make the fish unmarketable.