It just feels like one of those postapocalyptic movies. Factoring in the other creatures that live in the mussel beds and on the shore — barnacles, hermit crabs and other crustaceans, various worms, tiny sea cucumbers — puts the deaths at easily over a billion. — Christopher Harley, a marine biologist at the University of British Columbia
Like in ‘Postapocalyptic Movies’: Heat Wave Killed Marine Wildlife en Masse
An early estimate points to a huge die-off along the Pacific Coast, and scientists say rivers farther inland are warming to levels that could be lethal for some kinds of salmon.

Dead mussels and clams coated rocks in the Pacific Northwest, their shells gaping open as if they’d been boiled. Sea stars were baked to death. Sockeye salmon swam sluggishly in an overheated Washington river, prompting wildlife officials to truck them to cooler areas.

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

“It just feels like one of those postapocalyptic movies,” said Christopher Harley, a marine biologist at the University of British Columbia who studies the effects of climate change on coastal marine ecosystems.

To calculate the death toll, Dr. Harley first looked at how many blue mussels live on a particular shoreline, how much of the area is good habitat for mussels and what fraction of the mussels he observed died. He estimated losses for the mussels alone in the hundreds of millions. Factoring in the other creatures that live in the mussel beds and on the shore — barnacles, hermit crabs and other crustaceans, various worms, tiny sea cucumbers — puts the deaths at easily over a billion, he said.

... Such extreme weather conditions will become more frequent and intense, scientists say, as climate change, driven by humans burning fossil fuels, wreaks havoc on animals and humans alike. Hundreds of people died last week when the heat wave parked over the Pacific Northwest. A study by an international team of climate researchers found it would have been virtually impossible for such extremes to occur without global warming.
Read the full article: https://www.nytimes.com/2021/07/09/climate/marine-heat-wave.html