Ocean acidification takes toll on Pacific oysters

By

Lisa Duchene, SeafoodSource contributing editor

Published on
December 27, 2010

Editor’s note: This is the first of two features on ocean acidification. Look for the follow-up piece in January.

Sue Cudd, owner of Whiskey Creek Shellfish Hatchery on Netarts Bay in Tillamook, Ore., recalls 2005 as the last normal year for spawning oysters. To produce oyster, mussel and clam larvae by the millions, Whiskey Creek typically draws 200 gallons of seawater per minute into its hatchery — but can no longer count on natural seawater.

In late 2007, oyster larvae started dying in huge numbers. Die-offs continued throughout 2008; Whiskey Creek lost about 75 percent of its production that year. The oysters that survived, says Cudd, were sub-par.

“Batch after batch after batch with almost no survival,” recalls Cudd. “We’d lose millions and millions and millions of larvae. Maybe they’d look like they would make it, but then they wouldn’t. Or, they couldn’t develop. Even if they survived, they’d swim and swim and swim and never grow past 120 microns.”

In the same period, Taylor Shellfish Farms’ hatchery on Washington’s Dabob Bay also lost oyster larvae. In 2008, Taylor’s production was 60 percent below average and in 2009 it was down 80 percent. All told, the seed shortage translated to a 22 percent decrease in farmed Pacific oyster production between 2005 and 2009, according to the Pacific Coast Shellfish Growers Association.

While the two hatcheries, accounting for much of the region’s farmed oyster seed production, are located in places with different coastal dynamics — Whiskey Creek’s facility is right on the Pacific Coast while Taylor’s is nearly 80 miles from the open ocean, tucked within the Hood Canal estuary, sort of a fjord within a fjord — they are likely suffering from the same problem: acidifying sea water.

Click here to view the rest of the story on ocean acidification. Written by SeaFood Business Contributing Editor Lisa Duchene, the feature appeared in the December issue of SeaFood Business magazine.

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