British Columbia

Olympia oysters show resilience to ocean acidification, Oregon study finds

Olympia oysters, which are native to B.C. , have certain reproductive differences that make them more resilient compared to commercially raised Pacific oysters, say researchers at Oregon State University.

Researchers found that these native oysters take longer to develop their shells than popular Pacific oysters

Olympia oysters from Washington state. Researchers at Oregon State University have found that this species of oyster is more resilient to ocean acidification than commercially raised Pacific oysters. (LA Times via Getty Images)

As the oceans become more acidic more shellfish are struggling to survive — but researchers at Oregon State University have found that one particular species of oyster has a natural resistance to ocean acidification.

Olympia oysters, which are native to B.C. and much of the Pacific Northwest, have certain reproductive differences that make them more resilient compared to commercially raised Pacific oysters, said lead researcher George Waldbusser.

Waldbusser said that many bivalves "broadcast spawn" — meaning the eggs and spawn are released into the water.

Olympia oysters however, are fertilized internally before being released into the environment.

These oysters don't begin making their shells until two to three days after fertilization, compared to the Pacific oyster which only has a six-hour window to develop their shell.

"The fact that ... the female brood that larvae allows them to develop more slowly, and that slow calcification — or slow shell development — we believe is the reason why they show no response to these acute effects of ocean acidification in our experiments," said Waldbusser.

Balance between consumption, restoring populations

"Now we have to be careful because there are experiments that show in later stages that there are responses to acidification. But at this critical bottleneck that we've identified for a lot of other bivalves we just don't see it [responses to acidification] in the Olympia oyster."

The results of the study were recently published in the Journal of Limnology and Oceanography.

Olympia oysters once thrived along the Pacific Northwest coast of the U.S. and Canada, but their numbers have been severely depleted by overharvesting, industry and habitat loss, Waldbusser said.

Waldbusser said that some growers do raise Olympia oysters commercially, but said the challenge is that they grow slowly and are significantly smaller than Pacific oyster when they reach market size.

"They taste fantastic. They're a very different flavour than the Pacific oyster. But we need to be careful about a balance if we're working on restoring and conserving these species and their environment in addition to actually utilizing them for food," he said.

With files from CBC's On the Island


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