VANCOUVER -- The thousands of Atlantic salmon that escaped from a Vancouver Island fish farm on Friday will struggle to survive in open waters, according to a fish veterinarian.

The farm, Mowi, which boasts of being the world's largest supplier of farmed salmon, noticed one of its pens was heavily damaged on Friday, allowing some 21,000 Atlantic salmon to escape. Mowi believes an electrical fire may be to blame for destroying the pen and nets.

Some First Nations and environmentalists sounded alarms about the freed invaders, which they said could possibly devastate the already fragile wild salmon population.

But Dr. Hugh Mitchell, a Seattle-based expert who provides fish health services to the aquaculture industry, painted a bleak picture of the challenges farmed fish could face once they are released into the ocean.

"They are brought up on prepared fish pellets from since they start feeding," said Mitchell, owner of AquaTactics. "They don't know how to forage. They don’t know how to find rivers and reproduce. They get eaten by predators or they die of starvation after they escape."

Mowi also echoes that sentiment, adding it noticed several sea lions congregating near the damaged pen and suspect many of the salmon have already been eaten.

"Data would suggest there's a very low risk to the salmon making it to any rivers and an even lower risk of them establishing successful populations within the B.C. environment," said Diane Morrison, the managing director of Mowi Canada West.

Chief Don Svanik with 'Namgis First Nation in Albert Bay isn't convinced the farmed fish won't do any harm to the ecosystem, however, adding the uncertainty is cause for concern.

"Are they going to start spawning in our rivers? Are they going to push the native species out? Spread disease?" he questioned.

This isn't the first time salmon have escaped from a farm. In 2017, an estimated 300,000 fish were freed after a collapse at a farm near San Juan Islands in Washington.

At that time, American officials asked anyone with a fishing licence to capture as many salmon as they could.

Chief Svanik would like to see similar steps taken for this breach.

"Hopefully they can recover the fish. That will be very, very difficult," he said.

Morrison said the company is engaging with local First Nations and the federal government about efforts to capture the escaped salmon and monitor creeks and streams.

"I think the main concern we hear from many people is they're worried about them going into freshwater," she said.

The Department of Fisheries and Oceans said has been notified about the fish farm incident and said it is currently investigating.