A suspected act of sabotage that resulted in tens of thousands of penned salmon escaping into Passamaquoddy Bay is being investigated by Canadian authorities and has Maine officials worried about the possible effects on wild salmon in the eastern part of the state.

Alain Bryar, spokesman for the New Brunswick Department of Agriculture, Fisheries and Aquaculture, said Thursday evening that as many as 20,000 mature farmed salmon may have escaped from an aquaculture site off Deer Island, near Eastport, after netting on several floating pens was cut open. He said the damage appears to have been intentional.

“It’s incomprehensible to us that anyone would want to destroy” the pens, Bryar said.

The pens, owned and operated by Cooke Aquaculture, were vandalized either the night of Nov. 9 or early on Nov. 10, Bryar said, and the damage was reported to officials on both sides of the border the next day. Cooke, which also owns a processing facility in Machiasport and two hatcheries in western Maine, is trying to recapture as many of the escaped fish as it can, he said.

According to reports in New Brunswick, the estimated financial loss from the incident is $842,000, or $1 million in Canadian currency. Cooke is offering $125,000 in Canadian currency for any information about the vandalism that leads to a conviction.

George LaPointe, commissioner of Maine Department of Marine Resources, said Thursday that the state was notified promptly after the damage was discovered.

“They called us last Thursday,” he said. “Obviously, our concern is the impact of those fish on wild salmon on our side.”

Patrick Keliher, executive director of the Atlantic Salmon Commission, said the act was not the first to have occurred in western New Brunswick this year. He said Canadian aquaculture officials have indicated that an additional 20,000 fish escaped from another company’s vandalized pens in late spring or summer. Other reported escapes in the province have involved fewer fish, he said.

“What we’re hearing is that it is disgruntled employees,” Keliher said Thursday evening. “It’s a serious situation.”

The number of fish said to have swum out of Cooke’s six pens is an estimate, according to Keliher. He said that if each pen was at full capacity, it is feasible that nearly a quarter of a million farmed fish may have been let loose.

“Whether it’s 20 [thousand] or 120, it’s a significant escape,” he said.

The threat to Maine’s native salmon is that farmed fish will swim west into Maine waters, spawn with wild fish and compromise the unique genetic makeup of the native species, according to Keliher. He said the commission maintains a weir on the Dennys River in eastern Washington County but that high water levels from recent heavy rains have swelled the river level over the top of the weir, rendering it useless for keeping out the farmed fish.

The commission found in Maine waters farmed fish that had escaped after an earlier act of vandalism, Keliher said. Eight were captured in the Dennys River and 21 in the St. Croix River, he said.

“Unless the water drops in the next week, we’re not going to know how many fish are in the [Dennys River],” he said.