Oregon ocean acidification, oysters, crabs, salmons

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Oyster industry under threat from acidic seawater

On a normal day, the picturesque shoreline of Willapa Bay bustles with activity as oyster farmers harvest bushels of shellfish. Willapa Bay is located in the southern corner of Washington State, where 25 percent of all U.S.-grown oysters are farmed. Including oysters, clams, geoduck, and mussels, the shellfish aquaculture industry supports more than 2,700 jobs in Washington State alone, making these industries important economic drivers in the region.

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(Left) Willapa Bay, located in the south-western corner of Washington State, is a major hub for oyster farming. (Right) Two farmers pick oysters by hand at low tide in Willapa Bay in 1969. Many oyster farmers come from families that have harvested oysters for generations, but ocean acidification threatens the livelihoods of oyster farmers and others in the shellfish industry. (Image Credit: left, Sam Beebe/EcoTrust; right, Bob Williams).

Unfortunately, changes in ocean chemistry driven by carbon dioxide emissions threaten these vital industries, along with the biodiversity in Willapa Bay and across the waters of the Pacific Northwest.

From the industrial revolution to 2013, roughly 392 billion tons of carbon dioxide have been released into the atmosphere. Fortunately for the climate, one-quarter of this carbon has been absorbed by the ocean, which has significantly offset atmospheric warming. However, since carbon dioxide turns into carbonic acid once dissolved in seawater, the increase in atmospheric carbon dioxide has made the ocean more acidic.

Ocean acidification is considered to be a long-term impact of climate change, but some regions are already being forced to grapple with its effects. In the Pacific Northwest, where upwelling currents pull cold acidic water from the deep ocean up to the surface, marine life and the livelihoods that depend on it are beginning to suffer.

Ocean acidification primarily affects corals, shellfish, and other marine organisms that rely on the ocean’s chemistry to form calcium carbonate shells or skeletons. As seawater becomes more acidic, those organisms become less able to form their critical support structures, threatening their survival.

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Oyster larvae develop in normal (left) and acidic (right) seawater. Ocean acidification has the greatest impact on the early stages of oyster development when shell growth occurs rapidly. (Image Credit: Oregon State University).

Commercial oyster farmers in Washington have already begun to see the effects. Die-offs of oyster larvae from 2005 to 2007 in Willapa Bay, a major source of wild oyster seed, were among the first in a series of mysterious mass mortalities. In 2008, a hatchery owned by Taylor Shellfish witnessed die-offs as well, decreasing their output of oyster larvae by 60 percent.

Throughout the region, the oyster fishery has seen production losses of $110 million in Pacific hatcheries. Scientists have also noticed thinning shells in zooplankton, tiny microorganisms that form a key base of the marine food chain. This change carries implications for salmon and other economically important fisheries in the region that depend on zooplankton as a food source.

For industries and communities along the Pacific Northwest coast, the threat posed by ocean acidification is dire and immediate, but also poorly understood. More research is needed to better understand and predict crucial components of ocean acidification, such as the cause, timing, and location of changes in ocean pH.

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A farmer holds an oyster at Whiskey Creek Shellfish Hatchery in Netarts Bay, Oregon. For industries and communities along the Pacific Northwest coast, the threat posed by ocean acidification is dire and immediate, but also poorly understood. (Image Credit: Oregon State University).

Recognizing the problem posed by ocean acidification, former Governor Christine Gregoire convened Washington’s Blue Ribbon Panel on Ocean Acidification in 2012, a collaborative effort between scientists, shellfish industry representatives, policymakers, and tribal leaders. The panel is addressing the regional challenges posed by ocean acidification by identifying research and monitoring needs, developing recommendations about how to respond to its effects, and improving regional coordination to increase public awareness about ocean acidification. The panel identified key early actions as necessary steps to begin mitigating the effects of ocean acidification: reduce land-based nutrient pollution, cut carbon emissions, and boost forecasting capabilities to predict water chemistry changes.

While ocean acidification continues to threaten fisheries in the Pacific Northwest, the Blue Ribbon Panel has successfully initiated a dialogue between scientists and shellfish growers and helped to elevate the issue to the national stage. California, Oregon, and British Columbia joined Washington to form the West Coast Ocean Acidification and Hypoxia Panel in 2013 to build upon the work of the Blue Ribbon Panel. The leadership displayed by Washington State in response to the plight of shellfish growers has made real impacts on the way scientists and policymakers collaboratively discuss and plan for ocean acidification.