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Environment: Abalone threatened by climate change

The inside of an empty abalone shell. The sea snail could face threats from rising ocean carbon dioxide levels, according to research from the University of British Columbia.

New research give direct evidence that global warming threatens an endangered species

By Summit Voice

SUMMIT COUNTY — Already under pressure from poachers, the northern abalone could be pushed to the brink of extinction by rising levels of ocean carbon dioxide, according to a new report from the University of British Columbia.

Northern abalone are prized as an edible delicacy and formed a staple for some coastal tribes, But the slow-growing sea snail has been over-fished to the point that some species are listed as endangered.

The research by university biologists provides some of the first direct experimental evidence that changing sea water chemistry is negatively affecting an endangered species.
To better understand the impact climate change — and specifically, increasing ocean acidity — has on this endangered species, UBC researchers exposed northern abalone larvae to water containing increased levels of CO2. Increases from 400 to 1,800 parts per million killed 40 per cent of larvae, decreased the size of larvae that did survive, and increased the rate of shell abnormalities.

“This is quite bad news, not only in terms of the endangered populations of abalone in the wild, but also the impact it might have on the prospects for aquaculture and coastal economics,” said Christopher Harley, associate professor with the university’s department of zoology and one of the authors of the study. “And because the species is already thought to be limited by reproductive output and recruitment, these effects are likely to scale up to the population level, creating greater limits on population growth,” he added.

Average CO2 levels in the open ocean hover at 380 parts per million, a number which is excepted to increase slowly over the next century.

What concerns the researchers are the much higher spikes in dissolved CO2 that are already being observed along the BC coast, particularly in late spring and early summer when northern abalone populations are spawning.

The findings were published in the latest issue of the Journal of Experimental Marine Biology and Ecology.
“While we’re looking at a single species that is culturally important as a source of food and artistic inspiration for many coastal Pacific Northwest First Nations, this information may have implications for other abalone species in other parts of the world,” said Ryan Crim, lead author on the paper who conducted the research while a graduate student with the UBC Department of Zoology.

Other species of abalone are farmed around the world, principally in China, Taiwan, Japan and Korea. The black, white and pink abalone are also endangered on the west coast, while red abalone are still an economically viable food species.

The study was funded by the Natural Sciences and Engineering Research Council of Canada and conducted in collaboration with the Bamfield-Huu-ay-aht Community Abalone Project, a small abalone hatchery in Bamfield which has subsequently gone out of business. The dual mission of the hatchery was to produce cultured abalone for high end restaurants, and to restore endangered abalone by culturing and releasing larvae and juveniles to the wild.

Harley and Crim will continue to work with the aquaculture industry to study the effects of acidification on oysters and other shellfish.

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