Billions of sea creatures perished in Northern Hemisphere heatwaves

Extreme Weather

Billions of sea creatures perished in Northern Hemisphere heatwaves

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Experts say billions of mussels, starfish and clams died in soaring coastal temperatures while heat, fires and smoke impacted animals on land.

The heatwaves across the Pacific Northwest in late June and early July weren’t just deadly for humans, they also had an unprecedented impact on animals both on land and at sea. 

With temperatures at an all-time high of 112 F (44.4 C) in places such as Portland, Oregon and 107 F (42 C) in British Columbia, more than one billion ocean species are believed to have died off the Canadian West Coast alone. 

Chris Harley, marine biologist at the University of British Columbia, estimates that more than one billion sea animals cooked to death in soaring low tide temperatures due to the heat. The beaches of Vancouver were lined with tens of thousands of dead mussels, clams, snails and starfish and the smell of rotting shellfish was, as Harley said, “overwhelming.” 

estimates that more than one billion sea animals cooked to death in soaring low tide temperatures due to the heat.

“If you’re losing a few hundred or a few thousand mussels for every major shoreline, that quickly scales up to a very, very large number,” Harley said in a Canadian Broadcasting Corporation (CBC) interview. “Eventually, we just won’t be able to sustain these populations of filter feeders on the shoreline to be anywhere near the extent that we’re used to,” he said.

The heatwaves, which have also been linked to human deaths, with over 700 dead in British Columbia due to the heat at initial counts, have had a seismic effect on the environment. Harley and his team recorded temperatures above 122 F (50 C) at low tide on rocky shoreline habitats where mussels, starfish and clams live. 

While intertidal animals such as mussels can live in warm temperatures for a short period of time, the amalgamation of blazing heat and low tides during mid-day, for over six hours each day, made it impossible for the animals to survive, Harley said. 

“If you’re losing a few hundred or a few thousand mussels for every major shoreline, that quickly scales up to a very, very large number.”

The heat has had devastating ecological impacts beyond the immediate impacts. Harley said that water quality temporarily decreases after such a die-off as mussels and clams help filter the sea. Although mussel beds are likely to return to pre-heat waves conditions over time, the frequency of heatwaves is expected to increase due to climate change, indicating further decline in water quality. 

Researchers from Bamfield Marine Sciences Centre plan to deploy sensors in sea habitats around Vancouver Island this summer to further understand the impact the heatwave had on marine life in the region. 

Drought, extreme heat and fire have impacted whole coastal regions, rivers and other wildlife habitats in U.S.’s Pacific Northwest as well with more heat expected in mid-July.

“We’ve never seen these temperatures this early,” Jerry White, executive director for the organization, Riverkeeper, told local media. 

Up to 60 large fires have been burning across states from Arizona to Montana according to the National Interagency Fire Center.

Fish species such as the native Redband trout and Sockeye salmon in Washington state were at risk with river water temperatures reaching 80 F while on land, ecologists were concerned for species such as deer, elk, moose, sage-grouse and mountain goats who had no way to escape extreme land temperatures.

Up to 60 large fires have been burning across states from Arizona to Montana according to the National Interagency Fire Center. Satellite photos show smoke across much of the West with more than 850,000 acres alight and air quality alerts in place for numerous states and in parks such as Yellowstone National Park. And while humans are heavily impacted by the smoke, animals have nowhere to go to find relief. 

“If we don’t like [this],” Professor Harley said in an interview, “then we need to work harder to reduce emissions and take other measures to reduce the effects of climate change.”

Written by

Maheep Chawla

Maheep is a third-year undergraduate student at the University of British Columbia in Vancouver, Canada. She is pursuing a major in Psychology. Previously, she has interned with a pre-school for children with special needs based in New Delhi. In the past, she has also written for her campus newspaper and the editorial department at UBC’s Psychology Student Association.