Atlantic salmon in eight Maine rivers had been on the endangered species list for just a week when a potential threat to the wild fish became a reality.

On Nov. 20, a boat slammed into an Eastport aquaculture pen, tearing a hole in the netting and releasing as many as 13,000 farmed salmon within striking distance of at least one of the rivers where wild salmon are now listed as endangered.

But Heritage Salmon Inc., a division of Connors Bros. Aquaculture, isn’t in line for any sanctions under the Endangered Species Act, according to Mary Colligan, the chief of protected resources for the National Marine Fisheries Service.

“They did everything we’d asked them to do,” said Colligan. “They contacted us and made every effort to capture the fish.”

In deciding to list the Maine salmon as endangered, both the National Marine Fisheries Service and the U.S. Fish and Wildlife Service identified interactions between farmed salmon and Maine’s few remaining wild salmon as a serious threat to the genetic integrity and health of the wild fish.

Colligan said last week’s escape was a concern because the Eastport pen is close to the Dennys River, one of five Washington County rivers where the salmon are listed as endangered.

But Colligan said she’d be more concerned if the fish that escaped into Passamaquoddy Bay were sexually mature.

She also remarked that this was the first time the aquaculture industry reported an escape to the federal fish agencies. George LaPointe, commissioner of the Maine Department of Marine Resources, called her last Wednesday, she said.

DMR and Maine’s salmon aquaculture industry have been at loggerheads with the federal fish agencies for years. Salmon growers and state officials maintain that farmed salmon do not pose a threat to wild salmon and that additional regulations – such as reinforced cages and discontinuing the use of European-strain salmon – aren’t warranted.

Despite the accident, Bill Robertson, director of aquaculture operations for Heritage Salmon Inc., said his company continues to believe they’ve taken every precaution to keep the farmed fish in their cages.

What happened last week was “clearly an accident,” he said.

Robertson said an independent contractor was moving salmon from one site to another last Monday night when his boat hit one of the salmon cages.

The pen contained 72,000 2- to 21/2-pound salmon that had been put into ocean cages last spring. Robertson said the company has accounted for 57,000 of those fish.

The accident occurred about 8 p.m. and the company immediately attempted to employ a seine net around the boat and the cage, he said.

Divers were on the site within an hour and a half to two hours and, after the seine was in place, the boat was extracted from the net, he said.

“We immediately started pumping fish out, and we worked all night and all through Tuesday,” Robertson said.

Workers threw feed into the water to attract escapees back to the site, but with little success, he said.

Robertson said DMR has issued Heritage Salmon a temporary gill net license until the end of December so that the company can catch escapees in the bay. Heritage Salmon has offered to rebuild the weir on the Dennys Stream to keep any escapees from entering the river, he said.

“We’re also reviewing our fish recovery protocol,” Robertson said.

Calls to DMR were not returned Wednesday afternoon, but Fred Kircheis, executive director of the Maine Atlantic Salmon Commission, said the escaped salmon would probably mill around in the ocean.

“Atlantic salmon don’t have a need to go into rivers until they are sexually mature,” he said. “These salmon won’t be sexually mature for another two years and I don’t think they’ll survive that long.”

Kircheis said he believes Connors Bros. did everything right, including immediately notifying DMR of the situation.

Representatives of the federal fish agencies, Maine’s aquaculture industry and DMR have been meeting to discuss new regulations for several months. Colligan said the group hasn’t met since the listing, but that the recommendations the fish agencies have made to the Army Corps of Engineers are on the agenda for the next meeting.

NMFS and U.S. Fish and Wildlife have asked the Corps to include a number of conditions in the permits it issues for aquaculture sites, according to Paul Nickerson, the chief of endangered species for the Northeast Region of the U.S. Fish and Wildlife Service.

In an interview after the listing, Nickerson said those conditions include: better containment systems; marking of all aquaculture salmon so that escapees can be traced back to the company that raised them; no use of European-strain salmon; contingency plans for recovering escapees; and long-term monitoring.