Like in ‘Postpocalyptic Movies’: Heat Wave Kills Marine Wildlife


In the Pacific Northwest, dead mussels and oysters cover the rocks, their shells opening as if they were boiled. Sea stars cooked to death. Sockeye salmon swam slowly in the overheating Idaho river, prompting wildlife officials to move them to cooler areas.

The combination of extreme heat and drought that has hit the western United States and Canada in the past two weeks has killed hundreds of millions of marine animals and continues to threaten unknown freshwater species, according to a preliminary estimate and interviews with scientists.

“This feels like one of those post-apocalyptic movies,” said Christopher Harley, a marine biologist at the University of British Columbia who studies the effects of climate change on coastal marine ecosystems and calculates the death toll.

Such extreme conditions will become more frequent and intense, scientists say, as climate change caused by humans burning fossil fuels harms both animals and humans. Last week, hundreds of people died when a heatwave parked in the Pacific Northwest. A study by an international team of climate researchers discovered that it would be almost impossible For such extremes to happen without global warming.

Just before the heat wave, Dr. When Harley received the dazzling forecasts, she thought about how low the tide would be at noon, cooking the exposed mussels, sea stars, and mussels. When he went to the beach on one of the hottest days last week, the stench of decay hit him immediately. The scientist in him admitted that he was excited to see the real-life impact of something he had been working on for a long time.

But the mood quickly changed.

Dr. “The more I walked and saw, the more sobering it all got,” Harley said. “It just went on and on.”

Dead sea stars, often the most spectacular creatures in tide pools, hit him especially hard. But the obvious mass victims were the blue mussels, an ecologically important species that feeds on starfish and sea ducks and creates habitat for other animals. Dr. Harley estimated losses from the mussels alone in the hundreds of millions. Factoring in the smaller creatures that live in the mussel beds — mussels, hermit crabs and other crustaceans, various worms, small sea cucumbers — easily puts the deaths in over a billion, he said.

Scientists are just starting to think about domino effects. One concern is that sea ducks that feast on mussels in winter before migrating to their summer breeding grounds in the Arctic have enough food to survive the journey.

“At least it’s something we’re starting to think about,” he said.

He noted that the species living in the tidal zones were resilient and the mussels on the shady north side of the rocks survived. But if these extreme heatwaves happen too often, the species won’t have time to recover.

As the heatwave over the Pacific Northwest eased, the sweltering temperatures remained in much of the West of the Americas. now, looks like another heat wave is forming, only worsening the ongoing drought.

This means biologists are monitoring river temperatures with alarm. Salmon make an extraordinary migration, often hundreds of kilometers, from inland rivers and lakes where they are born to the sea, and then to spawn the next generation. The long-standing network of dams in the western states already makes the journey dangerous. Now, with climate change’s worsening heat waves and droughts, scientists say conditions look grim without the intense intervention that comes with its own risks.

“We’re in critical temperatures three weeks before the most serious warming occurs,” said Don Chapman, a retired fisheries biologist who specializes in salmon and steelhead trout, when speaking of conditions with four dams along the Snake River in Washington. long debated. “I think we’re headed for disaster.”

The state of salmon shows a broader threat to species of all kinds as climate change worsens. Many animals were already struggling to survive due to human activities degrading their habitats. Throw in extreme heat and drought and their chances of survival are reduced.

As an emergency measure, workers at the Idaho Fish and Game agency began catching a variety of endangered sockeye salmon in the Lower Granite dam, putting them in a truck and driving them to hatcheries as a temporary measure to decide the next step. (Idaho game officials first tried transporting adult fish by truck during a heat wave in 2015. This was done for juvenile salmon in a variety of runs for a variety of reasons.)

Biologist Jonathan Ambrose of the National Oceanic and Atmospheric Administration in California’s central valley said he wished we could do something similar. The chinook salmon he observed spawned in the mountains, historically. But since the Shasta Dam was built more than a quarter of a century ago, they adapted by breeding right in front of the mammoth structure they couldn’t pass through. The critical issue this year is that the water there is expected to get too hot for the eggs and fry. Previous efforts to secure state or federal funding to get them through the dam have failed.

“We’re looking at a mortality rate maybe 90 percent, or even higher this year,” said Mr Ambrose.

Elsewhere in California, for the first time since the state built the Iron Gate Fish Farm on the Klamath River in 1962 to make up for lost spawning habitat, state biologists won’t release their young salmon into the wild because they’re likely to die. Instead, they spread a million young salmon among other hatcheries that can house them until conditions improve.

University of British Columbia marine biologist Dr. “I want to find the positives and there are some, but it’s pretty overwhelming right now,” Harley said. “Because if we get too depressed or too depressed, we won’t keep trying. And we have to keep trying.”


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