Historic drought behind B.C. wildfires, salmon die-off could continue, experts say

Dead fish are shown in the Neekas River on Heiltsuk territory, B.C. in this recent handout image provided by Sarah Mund. Thousands of dead fish, a prolonged wildfire season and intense water shortages leading to ice rink closures are all symptoms of record-setting drought in parts of British Columbia. THE CANADIAN PRES/HO-Sarah Mund

Vancouver -

Thousands of dead fish, a prolonged wildfire season and intense water shortages leading to ice rink closures are all symptoms of record-setting drought in parts of British Columbia.

The Lower Mainland, Sunshine Coast and West Vancouver Island areas are experiencing Level 5 drought conditions - the most severe in the province's classification scale, which the B.C. government's drought information web page says means adverse impacts are “almost certain.”

John Richardson, a University of British Columbia professor in the department of forest and conservation sciences, said the current stretch of parched conditions is an anomaly for the province.

“This is quite prolonged,” he said in an interview. “This is the warmest, driest September we've ever had on record.”

Though Environment Canada is calling for a chance of rain in some parts of the province Monday, David Campbell, head of the BC River Forecast Centre, said the dry weather could persist for at least another week, “if not several weeks.”

Experts say the drought conditions have already brought on significant adverse effects.

Thousands of dead wild salmon were found last week in the Neekas Creek, which runs through Heiltsuk Territory in the central coast region of the province.

William Housty, conservation manager for the Heiltsuk Integrated Resource Management Department, said he has seen pre-spawn mortality before “but never to this degree.”

“We're looking at pretty much 100 per cent mortality of all the salmon that were in the creek at that time. It's just unheard of at this time of year that we don't have rain,” he said.

High tides and plentiful rain earlier in the season allowed the salmon to enter the river, Housty explained, but the following weeks of drought conditions dried out waterways and prevented the fish from spawning.

Oxygen levels dropped, the water temperature rose, and the result was massive die-off, he said.

“The Neekas is definitely the worst-case scenario. I don't think the die-off that large is happening everywhere. But definitely what we're seeing consistently across the board, is that the river levels are so low that the salmon just aren't in them,” Housty said. “And if they are, they're dead.”

Zoology professor Eric Taylor said though the images on social media of waterways clogged with floating dead fish are compelling, it's important to understand that the drought impacts are local.

“You can't really extend what's happening in a reasonably limited area to across the province as a whole and infer Pacific salmon everywhere are under stress because of this,” Taylor said.

And it's not the drought alone that is of concern for the salmon, he added.

“Fish can handle drought. They've handled it for thousands of years - it's just one of a myriad of challenges that they face,” Taylor said. “It's when these challenges pile on top of each other that the real issues for fish happen.”

He said the best solution is to ensure fish can easily access refuge areas, which would allow them to more easily adapt and survive during droughts.

Meanwhile, the Sunshine Coast Regional District delayed the opening of a local ice rink after the government implemented water restrictions amid concerns there wouldn't be enough for homes, fire protection and the Sechelt Hospital.

The BC Wildfire Service also issued a news release ahead of Thanksgiving weekend urging people to use caution and remain vigilant to prevent human-caused fires. The government has banned open fires in much of the province.

“Sustained warm and dry weather will extend British Columbia's wildfire season well into the fall,” the statement said.

As of Sunday, there were more than 185 wildfires still burning across the province.

The service said a cold front is expected to sweep across the province Monday, but that winds associated with the weather pattern may create “elevated fire behaviour conditions.”

“Very little precipitation is expected to accompany the front,” it said.

Even when the rain returns, Richardson warned the dry conditions could create greater flood risks.

“The soils have been drying, they become hydrophobic and so when they first get moisture, it takes a while for the moisture to soak in naturally,” he said. “So, initially, it's very resistant and water runs off the surface and - especially on steep slopes - that leads to lots of erosion and potentially slope failures.”

But floods are a worst-case scenario that would also require heavy rainfall in a short amount of time, Richardson said.

“Best-case scenario is it starts to drizzle, and everything gets wetted up, and we don't see anything happen at all,” he said.

This report by The Canadian Press was first published Oct. 9, 2022.