Ocean Acidification

From 31 January to 2 February, more than 700 conferees from 30 countries convened at Seafood Summit 2011 in Vancouver, Bristish Colombia (BC). There they wrestled with how to improve the sustainability of commercial fishing and aquaculture.

Now in its ninth year, the event drew 40 per cent of its attendees from the seafood business. Industry personnel joined conservationists, researchers, and government officials in discussing a range of sustainability issues – marine spatial planning, traceability shortcomings, and next-generation aquaculture among them.

The toughest item on the agenda may well have been ocean acidification, which only recently has emerged as a major issue to those concerned with food security and the productivity of our seas.

Scientific and journalistic coverage of this problem has exploded; a search on Google Scholar shows more than 25,700 articles, most of them published since 2006.

Acidification results from CO2 in the atmosphere combining with sea water to form carbonic acid. The oceans absorb about a third of human society’s CO2 emissions every year.

Since the Industrial Revolution began, the ocean’s chemistry has changed hundreds of times more rapidly than in the 650,000 years that preceded it.

The results include a 30 per cent increase in hydrogen ions and a 16 per cent decrease in carbonate ions, which organisms use to make shells, skeletons, and reef systems.

These organisms create marine ecosystems and refuges (coral reefs) and provide food for fish (krill, pteropods, shellfish larvae) and humans (oysters, mussels, clams). Recent research reveals just how threatened such species are by acidification, especially in their early stages of growth.

In some places, the effects of acidification are amplified by compounding factors, such as nutrient runoff, phyloplankton blooms, and eutrophication.

Unfortunately, the “hot spots” worldwide appear to be the same waters that support the most productive fisheries, including upwelling zones, cold high-latitude seas, and estuaries.

Shellfish hatcheries that supply the AmericaWest Coast oyster industry are already  experiencing – and developing strategies to endure – severe effects on their vulnerable young larvae.

On the opening day of the Summit, Brad Warren, of the Sustainable Fisheries Partnership, moderated a panel on how the seafood industry can combat ocean acidification.

Bill Dewey, the Public Policy and Communications Director for Washington state-based Taylor Shellfish; Kristian Teleki of SeaWeb; and National Oceanic and Atmospheric Administration (NOAA) Scientist Richard Feely participated.

The event drew an SRO audience of 80 or so, leaving latecomers to linger in the hall and listen. Warren said the crowd indicated the growing awareness of the problem. A similar session at last year’s Seafood Summit in Paris attracted only 30 people.

Dewey told the audience of the crisis West Coast oyster growers recently faced. For Taylor, the largest farmed shellfish producer in the US, acidification is not a future threat estimated by modeling or projections.

“It’s here now, during 2007-2009, our hatchery production fell 70-80 per cent. Other West Coast operations were also devastated. At the Whiskey Creek Hatchery in Netarts Bay, Oregon, oyster larvae dissolved in their tanks,” Dewey said.

“Even hard-fouling of the intake pipes ceased. We believe corrosive water was a major factor and may well be part of why there has not been  a wild set of Pacific oysters on the Washington coast for six years.”

Water with a pH as low as 7.4 had been drawn from Dabob Bay, where Taylor’s main hatchery is located. Hatchery operators at Taylor and Whiskey Creek started monitoring CO2 levels and adjusting the depth and time of day when they drew seawater in order to avoid CO2-rich water that kills larvae.

The two firms have been able to restore about 75 per cent of the larvae production that they lost in earlier years, showing that “bad water” can be dodged, at least for now.

But immediate adaptation is only part of the solution for Taylor and other shellfish producers. Longer range, oyster growers are trying to cultivate more resilient broodstock, with scientists at Oregon State University and the U.S. Department of Agriculture‘s (USDA) Agricultural Research Service leading the research.

And Taylor has become active in promoting continued research, increased monitoring, and reduced carbon emissions.

“With the scientists telling us that the corrosive water upwelling on our coast is fifty years old we know this problem isn’t going away anytime soon” says Dewey.

“We’ve seen the impacts of these waters first-hand and feel obligated to speak out and make others aware of the serious consequences of carbon emissions.”

Mike Mitchell, Technical Director for The Seafood Company of the UK’s Findus Group, the second largest food brand in Europe, agrees.

On the Summit’s final day, Mitchell quoted Warren’s remark that “trying to prevent climate change by reducing emissions in the seafood industry is like trying to save a burning house by dousing a toothpick.”

Analysts estimate that the fishing industry contributes 0.2- 0.6 per cent of the world’s human-produced carbon emissions.

The take-home message for Mitchell is “Full speed ahead on reducing the seafood industry’s own emissions, but don’t stop there. Our real aim is to keep oceans making lots of fish. So the objective is not just to reduce our emissions.

“That’s good and necessary but not sufficient. The real promise here is to use the industry’s CO2 reduction/efficiency efforts as part of a larger awareness-building initiative leading to policy and governance that protect the climate and the oceans that sustain us.”

To Warren, the West Coast oyster larvae are “the proverbial canary in the coal mine.” He is concerned that fear of ocean acidification will paralyze people.

“If they think a problem is just too big, people tend to give up or ignore it. We have to realize that this is just another resource management issue. Reducing carbon emissions is doable and it need not cripple us economically.“

He cites the nation’s first mandatory regional cap-and-trade system, the Regional Greenhouse Gas Initiative. The 10 participating Northeastern and Mid-Atlantic states are capping and reducing CO2 emissions from the power sector.

“Far from killing jobs,” Warren says, “the RGGI is actually saving jobs in the Northeast’s industrial economy. Funds from the program pay for energy efficiency improvements that make companies more competitive and allow them to retain jobs instead of shutting down or moving operations overseas.”

“Acidification is a risk to seafood production, but it’s a risk that can be managed in at least two ways. One is to prevent the change in seawater chemistry from getting out of hand,” Warren says.

“That will require public policies to control the flow of acidifying wastes like CO2 and nitrogen into the ocean. The second way to protect seafood supplies is to monitor seawater chemistry closely so you can evade some of the harm that can’t be prevented.“

For the rest of the seafood industry, the lessons from Taylor and other oyster growers may be indispensible. They have demonstrated that it’s possible to adapt, dodge, and start working to confront the causes of this problem.

Seafood helps feed billions of people and the demand is steadily rising. As Mike Mitchell observed, the challenge now is to make sure the oceans keep making plenty of it.

Note: The December 2010 UN report on ocean acidification and food security can be downloaded from http://productiveoceans.org/studygroup/news

Eric Swenson, FiS, 21 February 2011. Article & video.