Mass mortality: A fish scientist follows a tip about deaths on BC salmon farms

On June 1, Stan Proboszcz loaded up his kayak and caught the ferry from his home on Powell River to Comox on Vancouver Island. The two hour drive that followed would take him past snow-capped peaks and deep forested valleys until he reached a ferry on the Gold River.

Plunging his kayak into the waters of Muchalat Inlet, Proboszcz embarked on an 18-kilometer paddle into the open Pacific Ocean—and he did it all with an anonymous tip.

An informant had told Proboszcz, a fisheries biologist with the Watershed Watch Salmon Society, that offshore salmon farms had been experiencing mysterious and mass die-offs and no one was saying anything about it.

“Yeah, it was a little crazy,” Proboszcz said of his decision to make the long trip. “But he didn’t know why they were dying.”

Before Proboszcz left, a colleague had tracked a number of boats supposedly bringing in fish along the southern tip of Vancouver Island and into the Nanaimo area. But according to the anonymous source, the boats had almost finished transporting all the fish.

Desperate, Proboszcz had tried to hire a speedboat and even a helicopter to see what was going on. But nothing worked and so he decided to take matters into his own hands.

Five hours into the Muchalat inlet, Proboszcz arrived at the fish farm he thought was the site of a large die-off. He sent a drone into the air and captured images of what he described as “plumes” rising from the surface of the farm.

“It’s like a sheen, like a sheet of oil. It’s probably rotting, like dead fish oil coming from the farm,” he said.

One ship, the Knight Dragon, appeared to be pumping something from the farm, while another hose appeared to be discharging water from the ship into the open ocean.

Proboszcz said he suspects they were inhaling dead fish that had sunk to the bottom of farm nets, then blowing the inhalant water out of the ship’s tank.

But without evidence, he couldn’t prove anything and thought he had come too late to see the scale of the mortality event.

The scientist camped on the nearby shoreline and when he returned, contacted the Department of Fisheries and Oceans.

Up to 1000 tons of fish are lost in one farm

In emails seen by Glacier Media, Brenda McCorquodale, DFO’s senior director of aquaculture management, said in a response to Proboszcz that the department was investigating the latest allegations and could not comment further.

McCorquodale told Proboszcz that the deaths were not isolated to a single farm, but “that high levels of mortality have occurred recently among farmed fish in areas of farms in Clayoquot Sound, Port Hardy, Clio Channel, Esperanza and Nootka”.

McCorquodale said three of the five open pen farms operated by Grieg Seafood had reported mortality events in recent weeks. The highest was at Muchalat Veri, the farm where Proboszcz had been kayaking, where McCorquodale said that over a 10-day period, 23 percent of the farm’s stock was lost. ,

The farm is licensed to hold up to 4,100 tonnes of salmon, meaning a 23 per cent loss could mean nearly 1,000 tonnes of dead salmon.

When Glacier Media asked a DFO spokesperson about the death rate, they said the cumulative deaths at each salmon farm ranged even higher — from four percent to 26 percent between mid-May and early June.

DFO biologists and veterinary staff traveled to Nootka Sound. They “confirmed that the mortality events were primarily caused by environmental conditions: extremely low oxygen events and harmful plankton in the marine environment,” the spokesperson wrote.

The DFO spokesman said that rain followed by sunny weather has led to algal blooms and lack of oxygen in the past.

In her emails to Proboszcz, McCorquodale noted an event in 2019 when a plankton bloom in Clayoquot Sound led to “significant losses to a number of farms.”

DFO did not respond to questions about why farm oxygenators did not prevent fish kills and whether sea lice or other pathogens played a role.

A spokesperson for Grieg Seafood declined a request to answer several questions about the fatality incident, instead referring to a news release on its website. The announcement echoed statements from DFO, saying the death was the result of low oxygen conditions.

“Due to these adverse environmental conditions and to maintain the welfare of our salmon, we were unable to treat and administer sea lice treatments during this time, resulting in higher than normal sea lice counts. for a short period of time.” the statement said in part.

It later added: “We remain committed to minimizing interactions with wild salmon in the areas where we operate.”

Proboszcz said he has requested veterinary reports from DFO but has not received them. He said the whole incident, especially the reason given for the deaths, worries him because the farm he visited had three times the legal limit for sea lice, while a nearby farm had 10 times the limit, according to numbers the companies provided. required to publish online.

“They are experiencing all these losses. Are the high levels of sea lice contributing to this? Because sea lice have been known to kill too. We don’t really know,” said Proboszcz. “The big concern is that juvenile salmon are migrating from this area. I witnessed this myself.

“What danger is this to wild fish?”

Researchers warn of increasing mass deaths

Mass die-offs of farmed salmon are increasing worldwide, with Canada experiencing some of the largest and most frequent mortality events, according to a study published in March.

“The worst of the worst cases are getting bigger,” Gerald Singh, a researcher at the University of Victoria’s School of Environmental Studies and lead author of the study, said at the time.

The latest death in Nootka Sound comes as the department is working to phase out open pen farming of Atlantic salmon on the West Coast.

On Wednesday, Energy and Natural Resources Minister Jonathan Wilkinson said the government will provide a five-year license extension to 63 open-net Atlantic salmon farms in BC, not removing them until the end of June 2029, when they will to be stopped. in favor of closed systems.

Proboszcz said he was “not excited” about the five-year extension, but has already heard from DFO staff that Wednesday’s announcement is likely to be followed by a new regulatory regime that will include the ban in law.

He said this should come with increased oversight of the industry, more investigations and more fines. When farms fail pathogen tests, they should have their licenses revoked or be forced to remove farmed fish to protect wild salmon, he said.

Even then, however, Proboszcz does not expect the mass deaths to end.

“We’re not going to stop looking at salmon farms,” ​​Proboszcz said. “We just have to be vigilant.”

– With files from The Canadian Press