Thousands of Atlantic salmon swim in Cooke Aquaculture's 24 sea sites, penned areas where the company farms salmon, off the coast of Maine. The Maine Department of Marine Resources will hold salmon in similar pens off the coast of Washington County. Credit: Nick Sambides Jr. / BDN

The state is investigating why an estimated 100,000 fish died at a salmon aquaculture site off Mount Desert Island and hopes to have an answer in a couple of weeks.

The die-off at the fish farm, located off Black Island between MDI and Swan’s Island, was reported by Cooke Aquaculture to Maine Department of Environmental Protection on Aug. 27, DEP spokesperson David Madore said Wednesday. That was 11 days after the company, which operates roughly two dozen salmon farms along the Maine coast, first realized they might have a problem.

“Cooke staff began noticing dead fish when divers were in the pens on Monday Aug. 16, 2021,” Madore said, adding that the department expects to release its findings “in early October.”

Madore did not release additional details Wednesday about the investigation but, according to Cooke spokesman Joel Richardson, the deaths were caused by “uncommonly low dissolved oxygen in the cages.”

He said Cooke first notified the Maine Department of Marine Resources, which oversees approvals for the fish farm, about the die-off and then later told other agencies, including the DEP.

“Mortalities are a part of all food production through farming and fishing no matter where they operate – on agricultural land or on the sea,” Richardson said. “A fish health incident is not a violation of a Department of Environmental Protection permit, but rather an unfortunate event which can happen naturally in aquaculture farming from time to time.”

The fish that died at the Black Island location make up only 10 percent of fish being grown at the site, which he described as “a low percentage.”

Cooke has violated Maine rules and regulations in the past.

In 2019, Cooke was ordered by Maine Department of Environmental Protection to pay more than $150,000 to fund a wild salmon restoration effort after the agency investigated Cooke for multiple violations at salmon pen sites that the company leases and operates in Hancock and Washington counties.

State officials said at the time that Cooke violated its operating permit by having too many fish in one or more pens and failing to conduct environmental sampling. The company also failed to follow a variety of clerical procedures that include timely filing of complete and accurate pollution sampling reports and timely submissions of fish spill prevention plans. The infractions violated the terms of Cooke’s operating permit, DEP rules and state law.

It also has faced fines in Canada, where the company is based.

In 2013, the company was ordered to pay half a million dollars in Canadian currency after it had used cypermethrin to kill parasitic sea lice that were harming fish at growing sites off Deer Island and Grand Manan Island, just across the border from Maine.

Investigators later determined that the pesticide, which is banned in Canada but is legal in the U.S., also killed wild lobsters on the Canadian side of the border. The pesticide had been purchased at a Calais feed and pet store prior to being taken across the border and used at nearby salmon pen sites in New Brunswick.

In 2018, Cooke was fined $12,000 in Canada for using a pesticide without permission at a salmon growing site off Campobello, just across the border from Eastport and Lubec.

More recently, in 2019 and 2020, the company had tens of thousands of fish die at sites in Nova Scotia and then in Newfoundland, according to Canadian news reports. In those cases, Cooke officials cited abnormal water temperatures as the likely cause.

Farmed salmon is considered one of the largest fisheries in Maine, both in terms of volume and value. In 2010 more than 24 million pounds of the fish, with a wholesale sales value of more than $76 million, were produced in Maine, according to the state’s Department of Marine Resources.

The state has not released production figures for the fishery since 2010 because Cooke has been the sole producer of farmed salmon in Maine, and the company’s production volume is considered proprietary information.

Three other firms are proposing to establish new, large salmon farms in Maine though. Nordic Aquafarms is looking to build a land-based salmon production site in Belfast, and Whole Oceans is planning to build another land-based salmon on a former paper mill property in Bucksport.

A third firm, Norway-based American Aquafarms, is proposing to farm salmon at pens in Frenchman Bay off Bar Harbor. Opponents of the American Aquafarms proposal have cited Cooke’s history of issues, and the potential for problems at other sea-based sites, as an example of why the marine resources department should not approve American Aquafarms’ application to lease 120 acres in the bay for its salmon farm.

Bill Trotter

A news reporter in coastal Maine for more than 20 years, Bill Trotter writes about how the Atlantic Ocean and the state's iconic coastline help to shape the lives of coastal Maine residents and visitors....