Potential Impact of Ocean Acidification on West Coast Shellfish Aquaculture

In the Pacific Northwest seasonal upwelling of deep, CO2-enriched ocean water combines with the influence of anthropogenic CO2 emissions to compound changes in seawater chemistry. Two of the West Coast's major shellfish hatcheries have experienced significant declines in oyster larvae production that may be explained by coastal upwelling of these high CO2, low pH corrosive waters. In addition, in Willapa Bay, the largest oyster producing bay on the West Coast, where many growers have come to rely on natural recruitment of oyster seed, the set has failed to occur for six years. These natural set failures may also be attributed at least in part of upwelling of corrosive seawater. The combination of these impacts on hatchery and natural seed recruitment has resulted in about a 20% decline in West Coast oyster production over the past five years. Incorporating sophisticated real time monitoring systems has allowed hatcheries to successfully dodge the corrosive water events and significantly improve production. In addition, to help the shellfish industry adapt, scientists are working on how to manipulate seawater chemistry in the hatchery to allow larvae production when the corrosive water can't be avoided. They are also exploring rearing oysters bred to survive the corrosive conditions. In addition to monitoring and adapting shellfish growers are also speaking out about their experiences hoping to serve as the proverbial canary in the coal mine. They are hopeful this very real impact will help policy makers and others who are concerned about the health of our oceans understand the implications of unchecked carbon emissions for the marine food web.