Low water levels affecting salmon migration in B.C. rivers, DFO says

Low water levels caused by years of severe drought, combined with low snowpack and low precipitation, are leaving British Columbia salmon in a compromised position during their spawning migration, a fisheries expert warns.

Researchers are also trying to understand the effects of last year’s devastating wildfires in British Columbia.

Salmon need a steady flow of fresh, cool water to survive and reach their spawning grounds, but Murray Manson, section leader of the Department of Fisheries’ Centre of Expertise for Habitat Restoration, said in a briefing Friday that he expects fish to start showing up in some low-water areas.

“We are trying to prepare for some of the problems that might arise,” he said.

Concerns persist despite a cool spring that left British Columbia in a “luckier” position than expected, Manson noted.

“We’ve done pretty well so far, I would say, with respect to the drought and its impacts on fish,” he said.

Some areas, such as the Fraser River basin, where salmon runs were expected to be historically low, are currently in a wait-and-see situation, Manson said.

“They’re still swimming in the drought conditions upstream,” he said of the salmon. “(But) it’s still early. Things are still evolving.”

The ministry said in a statement that drought and heat can have a range of negative effects that could harm salmon survival in British Columbia this year.

He said low water levels can prevent salmon from accessing spawning areas and expose them to predators, while warm water can harm fish health, reducing their spawning ability and making salmon vulnerable to disease.

In the Kamloops area, the Department of Fisheries said the habitat restoration centre, which works closely with First Nations, stewardship groups, academics and salmon advocates, aims to mitigate the effects of drought on its salmon runs.

For example, on the Deadman River, his salmon restoration team is working to restore riparian areas of black cottonwood “so that these ecosystems can once again regulate water temperatures and provide cool refuges for fish.”

On the Adams River, which the department says is home to one of the largest sockeye salmon runs on the continent, researchers are assessing how the 2023 Bush Creek East wildfire affected the river and its vegetation.

“Our salmon habitat restoration team combines historical imagery and maps with real-time, high-resolution field data collection to understand how and where post-fire conditions are affecting fish habitat, including impacts on salmon spawning conditions,” the department said in a news release.

Manson said they are working on dozens of restoration projects and testing them to see what works, with the hopes of applying them more broadly across the landscape.

He said that while each project can be seen as a drop in the ocean, developing techniques that can eventually be used on a large scale can “really make a difference.”

In the meantime, the fisheries ministry is asking people to avoid entering dried-up waterways as they could disturb “sensitive elements”.

Manson said people should act as if these waterways were “always productive” fish habitats to ensure vegetation is not disturbed.

Citizens are also asked to manage their water consumption, especially during periods of drought.

Finally, Manson said the department is asking people not to move fish they might find stranded due to low water levels, or fish that might be caught below a dry section of a waterway. Instead, they want people to notify the Department of Fisheries through its reporting line.

“There may be people who are already aware of the situation and are trying to take action,” he said of fisheries staff. “We may be able to move adult fish in some cases, but we would have the proper equipment to do it without causing them further harm.”

Approximately 40% of British Columbia is experiencing drought conditions where economic or environmental impacts are likely or almost certain, and such outcomes are possible in an additional 21% of the province.

— By Brieanna Charlebois in Vancouver

This report by The Canadian Press was first published Aug. 17, 2024.