Ocean acidification: Trouble for oysters

Tiny oyster larvae, compared to a nickelCould increases in ocean acidity be partly to blame for larval die-offs that have plagued Northwest oyster producers for much of the past decade? Scientists and growers believe that may be the case – and they’re struggling to help the region’s lucrative shellfish industry adapt to the risk.

In a recent blog post for the Sightline Institute, a Pacific Northwest sustainable policy center, former Seattle Post-Intelligencer reporter Jennifer Langston talks to growers and scientist who are concerned about ocean acidification and the threat it poses for oyster growers in the Pacific Northwest.

According to Langston, West Coast oyster production dropped from 94 million pounds in 2005 to 73 million pounds in 2009, resulting in an $11 million loss in sales for what had become a $72 million-a-year industry.

Langston interviewed researchers at Oregon State University who have embarked on a major, multi-year investigation of  the effects of ocean acidification on oyster production. Among that team is OSU researcher Chris Langdon, who has received Oregon Sea Grant support for his research on the health and production of oysters, abalone and other shellfish.

While Langdon and others have identified toxic organisms  such as Vibrio tubiashii as part of the problem, there are also signs that increasing ocean acidity is playing a role in the die-off of larval oysters, which appears to worsen when ocean temperatures and currents cause water that’s high in carbon dioxide and low in pH (acidic) to well up and mix with the “good” water normally found in the oyster breeding beds.

Using what researchers have learned from their ongoing study of the issue, two major oyster producers have been able to adapt their practices to ocean conditions. Using a monitoring buoy as an early alert to changes in seawater chemistry, they were able to schedule production for “good water” periods, resulting in a strong rebound in production in the 2010 season. But concern about the state of the oceans remains.

Read the entire article in Sightline Institute’s blog.

Read more about the NOAA research project and how it has helped growers adjust their aquaculture practices.

[Photo courtesy of OSU Extension Service]

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