Oysters and Ocean Acidification

by: Posted on: January 06, 2012

By Margaret Pilaro Barrette, Executive Director for the Pacific Coast Shellfish Growers Association

Editor’s Note: The Executive Director for the Pacific Coast Shellfish Growers Association takes us through her realization of the harm Ocean Acidification is doing to the oceans, shellfish populations, and a way of life for shellfish growers. Yet another reason to check our unfettered consumption of fossil fuels.

I am not a physical scientist. It’s not that I don’t “get” science, or that my palms get clammy when I hear about the scientific processes. I’m one of those people who when faced with something very scientific, is more interested in the “So what’s that mean?” or “How’s that going to impact people?” rather than the “Hey, how’d that happen?” I guess that makes me more of a social scientist.

About 18 months ago, I left my position at the WA Department of Natural Resources and began working as the Executive Director for the Pacific Coast Shellfish Growers Association (PCSGA). This organization has been around for over 80 years and is made up of shellfish farmers who produce oysters, mussels, clams and geoduck in Washington, Oregon, Alaska, California and Hawaii.

Within my first few weeks on the job, I attended the Association’s annual conference –the first day of which was entirely dedicated to the topic of “Ocean Acidification”. I was struck by all the long faces. I needed to learn more.

The learning process took me knee-deep into science. When water absorbs CO2 from the atmosphere, the CO2 is converted to carbonic acid. I learned that the water along the Pacific Coast is layered.  The top layer is made up of “newer water”, which comes from fresh water inputs like rivers and runoff.  “Older water” is deeper in the water column and because of its age has absorbed more CO2 and carbonic acid making it acidic or corrosive, with a lower pH. During certain weather events, such as a north west wind, the older water “up-wells” or rises towards the surface, bringing with it higher concentrations of CO2 and acidic water.

At one time the oceans were thought to be essential in helping us deal with the rise of carbon dioxide in the atmosphere – capable of storing large amounts of CO2. Now we realize that the ocean’s ability to store CO2 is impacting those that live within it. In the case of oysters, corrosive water makes the shells of oyster larvae dissolve faster than they can form. Oyster larvae need that early shell development in order to grow into a baby oyster “seed” and live a healthy life.

The folks at Whiskey Creek Shellfish Hatchery in Netarts Bay, Oregon first drew attention to this issue in 2007. At first they thought it was due to bacteria. Finding nothing, they turned to the pH levels of the water.

We now know that acidic water, with a low pH, is responsible for a significant decline in oyster larvae production at west coast shellfish hatcheries. It’s also likely responsible for the lack of natural oyster recruitment in the Willapa Bay region, as spawning events have not naturally occurred there in the past six years. This change in the water is clearly responsible for all the long faces and defeated spirits I witnessed at my first shellfish growers conference.

The oyster industry contributes over $270 million to Washington’s economy and supports 3,200 jobs. When places such as Willapa Bay don’t experience naturally occurring oyster spawning events for six years, those working in the industry as well as all who enjoy eating shellfish, lose. Shellfish is a high-quality protein that is sustainably produced under the most comprehensive environmental laws in the world, such as the Clean Water Act, the Endangered Species Act. The demand for Washington-produced shellfish far exceeds the supply and as we’ve seen with other American-produced products, foreign competition from China and New Zealand are standing by ready to fill the need. Importing foreign shellfish ignores the issue of Ocean Acidification, reduces jobs in rural communities, and introduces seafood into our markets that is produced without high standards for environmental sustainability or human health.

Acidic water (with low pH) kills Phytoplankton, a staple in the marine food chain and a major component of juvenile salmons’ diet. Other marine organisms such as crabs, corals, and shellfish depend upon carbonate to build skeletons and protective shells. As the amount of available carbonate in marine waters declines with acidity, the health of these species is compromised. We’re also learning that certain types of harmful algae blooms thrive in acidic waters.  During such a bloom, the algae release toxins that can kill fish, mammals, and birds and can cause human illness. Impacts to marine species also translate to impacts to the overall health of the marine environment. Bottom line – Ocean Acidification is bad news for everyone.

Researchers and shellfish hatchery operators on both the east and west coast are trying to understand and adapt to the changing conditions. Thanks to funding obtained by the Pacific Coast Shellfish Growers Association, monitoring stations exist at the Whiskey Creek Hatchery as well as in Bellingham, Dabob Bay, Gray’s Harbor and Willapa Bay. Among other things, these sites monitor for pH, temperature, salinity, and bacteria levels. By knowing the composition of the chemistry of the water, hatchery operators and shellfish farmers can adjust their schedules to work around times of low pH.

Unfortunately, Ocean Acidification can’t be addressed through a single piece of legislation.  In fact if we were to stop emitting carbon into the atmosphere today, we’d still experience acidic ocean water for decades.  But we can bring attention to the issue and demonstrate the related impacts.  Last spring, PCSGA hosted a Congressional Briefing on the issue of Ocean Acidification.  We were joined by our colleagues from Maine to express need for continued research funding and support of federal programs that conduct marine monitoring.

Turns out you don’t need to be a lab coat scientist to understand the basics of Ocean Acidification. You also don’t need to be a social scientist nor a shellfish consumer to appreciate why it’s bad. Chances are if you appreciate sustainably produced food, species diversity, and the many other values the marine environment provides, you probably want to pay attention to Ocean Acidification.

For more information visit NOAA’s webpage and search “ocean acidification” or visit the following links:



Also, to learn more about how University of Washington is playing a role go to:


P.S. from the Editor:

For more on Ocean Acidification and its impact on the Great NW see the Sightline Institute’s report on Northwest Ocean Acidification.

2 Responses to “Oysters and Ocean Acidification”

  • G'day Margaret Simplified the story of Ocean Acidification very nicely. I take issue to your implied comments on New Zealand's shellfish produced without high standards for environmental sustainability or human health. I'm an Aussie so its unusual I'd be sticking up for the Kiwis, but their environmental systems of production, and human health are world class, and having just finished visiting the US, Canada and Europe looking at shellfish production, I'd make the comment that this issue of Ocean Acidification and environmental influences on shellfish production is one that "we" as a global industry should be standing shoulder to shoulder on. The PCSGA does a great job uniting your growers together, and informing the public about the issues.  Keep up the good work. Regards Ian Duthie
    by: Ian Duthieon: Tuesday 6th of November 2012
  • ScienceDaily (May 12, 2008) — For members of the multimillion-dollar West Coast shellfish industry, their world is the oyster. Unfortunately, the oyster industry's ability to meet rising demands is hampered by two species of burrowing shrimp. So Agricultural Research Service (ARS) scientists are collaborating with colleagues from Washington State University and Oregon State University to develop sustainable shrimp-control strategies. Ghost shrimp and mud shrimp inhabit the tideflats in estuaries where West Coast oysters are raised. The shrimp burrow into the estuaries, making the intertidal mud soft and unstable. As a result, oysters and other shellfish can sink beneath the silty surface and suffocate. Brett Dumbauld, an ARS ecologist stationed in Newport, Ore., and his colleagues are uncovering information about the shrimps' habitats, life history and natural predators—information that can be used to help develop new methods to protect oysters from pests. ... http://www.sciencedaily.com/releases/2008/05/080509112525.htm
    by: Danon: Wednesday 28th of November 2012

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