The rocks of the Pacific Northwest are covered with dead mussels and clams, and their shells open as if they were cooked. Starfish are roasted to death. Red salmon swim slowly in a superheated river in Washington, prompting wildlife officials to truck them to cooler places.
According to a preliminary estimate and interviews with scientists, the extreme heat and drought that have struck the western United States and Canada over the past two weeks have killed hundreds of millions of marine animals and continue to threaten unknown species in freshwater.
"It feels like that kind of doomsday movie," said Christopher Haley, a marine biologist at the University of British Columbia who studies the impact of climate change on coastal marine ecosystems.
To calculate the number of deaths, Harry first looked at how many blue mussels lived on a particular coastline, how many areas were good habitats for mussels, and the proportion of deaths he observed among the mussels. He estimates that the loss of mussels alone is in the hundreds of millions. Considering that other creatures living in mussel beds and on the coast — barnacles, hermit crabs and other crustaceans, worms of all kinds, small sea cucumbers — the death toll easily exceeds 1 billion, he said.
Halley continues to study the damage and plans to publish a series of papers.
Scientists say this extreme weather condition will become more frequent and severe as climate change caused by human burning fossil fuels wreaks havoc on animals and humans. Last week, a heat wave ravaged the Pacific Northwest, killing hundreds of people. A study by an international climate research team has found that such extreme weather is almost impossible to occur without global warming.
Just before the heat wave arrived, when Harry saw the jaw-dropping weather forecast, he thought about how low the midday tide would be, roasting the mussels, starfish, and crustaceans exposed to the sea. On one of the hottest days last week, as he walked to the beach, the smell of decay immediately hit him. He admits that as a scientist, he was excited to see the true effects of something he had been studying for so long.
But his mood soon changed.
Harry said, "The more I walk and the more I see, the more sober I become."
Dead starfish is often the most striking creature in the tide pool, and it hits him particularly hard. But the most obvious victims are the blue mussel, an important ecological species that feeds starfish and sea ducks and creates habitats for other animals.
Scientists are just beginning to think about the domino effect. One concern is whether sea ducks will have enough food to survive their journeys. Sea ducks feed on mussels before migrating to summer breeding grounds in the Arctic in winter.
He noted that species living in the intertidal zone are highly adaptable, while mussels on the north side of the rocks in the shade appear to have survived. But if these extreme heat waves become too frequent, species will have no time to recover.
While the heat wave in the Pacific Northwest has eased, heat continues to be high in much of the western United States. Now another heat wave appears to be forming that will only exacerbate the ongoing drought.
This means that biologists are observing the temperature of the river in a manner of alarms. Salmon make an extraordinary migration, usually starting from the inland rivers and lakes where they were born, swimming to the sea, and then returning to spawn. Long-standing dam networks in western states have made this journey dangerous. Now, as climate change exacerbates heatwaves and droughts, scientists say the situation looks grim without stepped-up intervention, which also has its own risks.
Don Chapman, a retired fisheries biologist who specializes in salmon and trout, said, "With three weeks to go until the most severe warming, we are already at critical temperatures." "The four dams on the Snake River have been a point of contention." I think we're heading for disaster. ”
The plight of salmon suggests that all species face broader dangers as climate change worsens. As human activities degrade their habitats, many animals are already struggling to survive. Coupled with extreme heat and drought, their chances of survival are reduced.
As an emergency measure, Idaho AFCF staff have begun catching a variety of endangered red salmon at the Lower Granite Dam, dropping them on trucks and sending them to hatcheries as a stopgap measure to decide what to do next.
In California's Central Valley, Jonathan Ambrose, a biologist at the National Oceanic and Atmospheric Administration, said he hoped he could do something similar. The salmon he observed has historically been bred in the mountains. But since the shasta dam was built three-quarters of a century ago, they have multiplied in front of this behemoth, thus adapting to the environment, and they have been unable to cross this huge building. The key issue this year is that the water temperature there can get too warm, detrimental to the survival of eggs and juveniles. Previous attempts to obtain funding from the state or federal government to transport them through the dam have failed.