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One billion seashore animal deaths an ‘underestimate,’ researcher says

Study underway on Coast after June’s record-breaking heat wave

As temperatures on land hit record highs three days in a row late last month on the Sunshine Coast, researchers and residents alike noticed a putrid smell emanating from the shoreline. Thousands of shells were cracked open, tissues exposed – seashore life had been cooked alive by the heat wave.

“It smelled like death,” said Fiona Beaty, a PhD candidate at the University of British Columbia.

“Now if you walk along the beaches, there’s all of these empty mussel shells that have washed up, so the beaches are crunchy,” she said.

Beaty, who lives in Gibsons, is part of UBC professor and marine biologist Chris Harley’s lab studying marine life and how climate change affects organisms in the intertidal zone.

Soon after the heat wave, headlines reported Harley’s estimate that more than a billion seashore animals had likely died in the Salish Sea due to the extreme conditions.

When he first saw the forecast for the end of June, Harley said he expected some die off, but when he walked to his local beach on June 27, he could smell the rot before he saw it.

“Now that I’ve seen more shorelines, I’m convinced that that number is a substantial underestimate. It’s going to be way more than a billion animals have died,” Harley told Coast Reporter on July 13.

One of the flagship species to die was the mussels, which act as both food and habitat for other species. That temporary loss could take years to recover, Harley said, and is not limited to mussels.

The team is also studying the impact on barnacles, oysters, snails, clams, crabs and seaweed.

Questions remain as to the impact on species such as the migratory surf scoters, ducks that rely on mussels in the Howe Sound region for food before breeding in the Arctic. If those birds cannot eat enough mussels, Harley said researchers anticipate a potential impact on herring spawn.

“It’s possible that we’re going to have ripples out from the species that have died into all sorts of unexpected corners of the ecosystem,” he said.

Water quality

The curator at the Nicholas Sonntag Marine Education Centre, Jenny Wright, said there could also be a negative impact on coastal water quality.

“The mussels would usually filter the majority of bacteria and harmful algae out of these waters, therefore without them we may see an increase in harmful algal blooms along the coast,” Wright said in an email.

Part of the high mortality rate was caused by a low tide series that coincided with the heat wave. Beaty said the creatures were exposed to the high temperatures for much longer than they otherwise would have been.

Prior to the heat wave, Harley’s research team had already set up a study zone in the Selma Park area, where they had observed a different pattern of life in the intertidal zone. Normally different species will form layers on rocky shores, but in Selma Park, the pattern usually observed was turned sideways from north to south. Beaty said across the Sunshine Coast, the mussels that were growing on the south side of boulders, where they receive more sun, have largely died. On the north side, with more shade, those lifeforms were more protected and some survived.

“That decision a mussel made when it was a larva choosing where to attach had huge consequences on those hot days,” Harley said.

Secret Beach

When Michael Maser went snorkeling on July 10, the impact of the heat wave was obvious. At Secret Beach in Gibsons, he saw dead mussels and sea stars visible in the intertidal zone.

“I snorkel there frequently and I can assure you it otherwise supports a very healthy population of marine life,” Maser said in an email to Coast Reporter. “Not all the mussels are dead, many survived, but there are patches – like mange on a dog – where all the mussels have died.”

Five years ago, the Pender Harbour Ocean Discovery Station (PODS) began monitoring programs for the area’s 40 to 50 species in the intertidal zone. Michael Jackson, the executive director of the Loon Foundation that oversees PODS, said they knew an event like this was coming, and pre-emptively gathered data to track the changes, causes and effects.

Even though the intertidal zone is probably one of the most inhospitable places to live, he said the heat wave was “without a doubt devastating.” In the Pender Harbour area, Jackson said they’ve seen mussels and young crabs rotting away, and he worries the stagnating flesh is affecting the fish. He agrees with Harley that the mortality rate is much higher than the initial estimate of a billion.

Climate change

“This is such a clear example of how climate change is affecting our beaches right now,” Beaty said. “In our lab, we’re studying this with the expectation that it’s going to be like 10, 20, 50 years down the road. But when this happens, now we’re talking about what are the beaches going to look like next year? Are these animals going to be able to regrow? Or will we get another heat wave at this time of year that’s just going to knock things back again? It hits home on that deeper level.”

She also noted that the Salish Sea is heating up at twice the average rate of warming, because it is an inland body of water.

“This area might be a hotspot for the negative effects of climate change,” Beaty said, adding she hopes it will act as a red flag to raise awareness and engagement of people living on the Coast.

On the Sunshine Coast, Harley and his lab researchers are continuing to catalogue the extent of the damage from the heat wave in Halfmoon Bay and at Selma Park. Beaty has checked beaches in Gibsons and Roberts Creek on her own time. The team was also invited by a Garden Bay resident to examine the impact at her beach access, which Beaty says shows how much the loss has resonated with coastal residents.

“This is a tragedy, but the thing that I find inspiring about it is that people care and have been sending in their observations, and it gives me some hope that people still love nature,” Harley said.

“And if we love nature, we will continue to do things to try to protect it, which would include helping to mitigate the effects of climate change and future heat waves.”

The researchers are collaborating with others on B.C.’s coast and in Washington, and will submit a summary paper to a peer-reviewed journal later this year. In the meantime, Harley said residents interested in submitting their observations can contact him at [email protected].