Salmon used to be so plentiful in the river that old-timers talked of crossing behind fish so thick they were like steppingstones. Such is the fame of the Cowichan River, which flows east on Canada’s Vancouver Island, that its fishing conditions are posted on fishing clubs in London. John Wayne and Bing Crosby were regulars in Cowichan Bay.
So when hundreds of young salmon and trout were found dead in the river last month, even as record wildfires burned across Canada, the news made the front page of local newspaper. The die-off, the largest in living memory, quickly led to an investigation.
It remains a mystery. Government officials found partially treated wastewater in the river weeks after the fish were found, but have not yet drawn conclusions about its impact. Local scientists suspect that the bigger culprit is climate change, which has contributed to the decline of salmon populations in British Columbia through increased droughts and heat waves.
In a summer of global disasters for Canada, climate change has been felt across this vast country — from the Cowichan Valley on the Pacific Coast to Halifax on the Atlantic, from the long border of the United States to the most remote towns above Arctic Circle. But if the world is consumed by the fires raging in Canada’s forests, turned into tinderboxes from the effects of climate change, the river’s condition is close to home in the Cowichan Valley.
A biologist, swimming in a wet suit miles downriver from where the juvenile fish, or fry, were found, discovered hundreds of dead bodies in pools on the river bottom. Further downstream, past eerie “barren areas” devoid of fish, he found dozens of dead adults in larger, deeper pools — rainbow trout as long as of feet and larger browns.
“It’s the first time not only in my career, but the first time in my life, that I’ve seen something like that,” said biologist Tim Kulchyski, 50, who said he “grew up on the river” as a member of Cowichan Tribeswhere he now works as a natural resource specialist.
The mass die-off of cold-water fish comes during another summer of extreme drought and heat on Vancouver Island, a region known for its temperate climate. The wildfires cut off access to some of the island’s western communities for more than two weeks during the tourist season, leading to losses that a local chamber of commerce estimated around $30 million.
The country experienced a summer of extreme weather events and record-breaking temperatures. Inuit communities were destroyed, some above the Arctic Circle records with temperatures above 90 degrees Fahrenheit.
With at least a month left in the wildfire season, the blaze has burned an area equivalent to the state of Georgia, about 38 million hectares of forestmore than seven times the annual average. The fires have forced nearly 200,000 Canadians to flee their homes this year and led to the deployment of thousands of foreign firefighters to help, as experts called for a fundamental rethinking of forest management and Canadian firefighting.
In the Cowichan Valley, the effects of the province-wide drought are most visible in the river that has sustained indigenous communities for centuries and helped grow local industry and tourism. Recognized as a Canadian Heritage Riverthe Cowichan ecosystem cannot survive without direct human intervention, experts and local groups say.
“There’s a lot of talk about climate change, but living in it, there’s no denying it,” said Tom Rutherford, a salmon biologist and executive director of Cowichan Watershed Board.
“We’ve never had a significant fish kill like this in the Cowichan River, or at least in living memory,” Mr. Rutherford said. “The event is still under investigation. But if there was more water in the river, if it wasn’t this hot, the impact would be less. Salmon are cold water species. Things that tipped may not have existed in the past. to them on the sidelines. Now they’re doing it.”
Government investigators found partially treated wastewater from a local treatment facility in the river 14 days after the dead fry were first discovered, but have yet to reach any conclusions about “toxicity” or ” its impact on fish,” according to a spokesperson for Environment. and Climate Change Canada, a federal department.
In recent years, the government and other experts warn that increased droughts, heat waves and heavy rains exacerbated by climate change are leading to sharp decline of British Columbia’s salmon population, especially species that spend more time in rivers. Thousands of salmon have been found dead in the province’s Pacific Coast rivers and streams amid severe drought over the past two years. Stresses from habitat change also weaken fish and make them more likely to die from other causes, experts say.
From its source in Cowichan Lake, the river flows 30 miles southeast of Vancouver Island, in one of the most fertile areas in Canada, past forests once filled with towering cedars and Douglas firs, before flowing into the Salish Sea. The Cowichan is the perfect habitat for chinook, chum and coho salmon, which can burrow into insects and swim in the cool water shaded by trees.
Local Indigenous communities, according to their cosmology, are the people who descended from heaven to earth where they found a river full of salmon. The river and the salmon are central to their way of life and spirituality, said Lydia Whitsumthe leader of the Cowichan Tribes.
“The river and everything within the river is considered part of our family,” said Chief Hwitsum. “And it is our responsibility to watch over and protect it.”
Logging in the Cowichan Valley began after the arrival of European settlers in the mid-19th century, and continues to this day. In the 1950s, a weir was built on Cowichan Lake to provide water storage for a paper mill, storing and releasing water during dry months.
Residents age 60 and older remember periods of steady rain that fed the Cowichan and its tributaries, and cool, often cloudy summer months that kept the water favorable for in young salmon and trout. Some remember jumping off an old railroad bridge nicknamed the “Black Bridge” into the river — in a place where the water was maybe a foot deep.
The logging cut down many of the old trees that keep the river and valley cool and help absorb rain that is gradually released into the river, experts said. Today the rains have become irregular, often dumping too much water that the ground cannot absorb. Snowpacks are melting earlier due to warming weather, leaving less water for the river during the summer.
Joe Saysell, 75, a fishing guide who has lived all his life along the river, said the shape of the Cowichan has changed in his lifetime, becoming wider and shallower, its bottom covered with gravel and more low to medium-sized rocks under which the fry can feed on insects and hide from predators.
Since the heat wave in mid-August brought days with temperatures in the mid-80s to the region, Mr. Saysell said, “The poor fish are just cooking.”
Mr. Saysell, a retired logger and founder of Friends of the Cowichan, a private organization formed to protect the river, was one of the first to spot the dead fry last month after a friend who was swimming in the river with his son alerted him. a girl.
“This river is in the emergency room with a bunch of doctors trying everything they can to keep that patient alive,” he said.
This summer, in order to conserve water in the midst of a severe drought, the release of water from Lake Cowichan was restricted to the lowest possible level. About 10 days before the dead fry were found, the water flow in the river was reduced by more than a third.
The decades-old weirs are not capable of providing enough water in times of climate change, said Mr. Rutherford of the Cowichan Watershed Board.
The Cowichan Watershed Board is pushing for the construction of a larger weir that would store more water for the dry months, Mr. Rutherford said. In the climate of local government predicting projections hotter, drier summers and warmer winters, more human intervention is needed to keep the Cowichan alive, experts say.
In the past, the Cowichan River has gone through periods of drought but has always been able to regenerate. Today, that’s no longer possible, said David Anderson, who served as a federal environment minister two decades ago and is a board member.
“Nature corrects itself, but it cannot correct itself where man substitutes himself for nature and makes decisions contrary to any possible recovery,” Mr. Anderson said. “We are in another world. We’re just taking too much away from the environment around the world.”