Washington's oysters are a case study of hope in the face of environmental disaster

When climate change started killing the Pacific Northwest's oysters by the millions, scientists and growers taught the world how to safeguard an ecosystem. 

Illustration of oysters and the words "acidification"

In the late 2000s, Pacific Northwest oyster growers saw millions of their hatchery larvae die. Since then, they've developed numerous ways to mitigate the ocean acidification that caused the die-off. (Illustration by Morgan Krieg)

This story first appeared in Bitterroot, an online magazine about the politics, economy, culture and environment of the West.

Crossing the Cascades that October, a pall traveled with the oyster growers on their way to Central Washington’s Lake Chelan for their trade association’s annual meeting.

Their thoughts were locked on a pair of puzzles that, in the fall of 2008, remained unsolved. Why were oyster larvae — the seed from which they grow their crop — dying by the millions at Washington and Oregon hatcheries? And why had Washington’s Willapa Bay, among the most pristine estuaries in the lower 48 states, seen die-offs for four years running?

The smart money was on disease, one carried by a species of bacteria that had plagued the industry before. But bacteria was a problem they should’ve been able to fix. Hatchery managers just had to shut down, clean the pipes and fire up again. But they had already tried that. When the deaths continued, anti-microbial filters meant to catch bacteria were installed, at no small expense, in an Oregon hatchery. None of it worked. Then, at that Pacific Coast Shellfish Growers Association conference, Richard Feely announced the real culprit. 

The poison wasn’t something in the water, the National Oceanographic and Atmospheric Administration chemist explained. It was the water.

After 150 years of absorbing carbon dioxide we’ve pumped into the atmosphere, the seawater sloshing through inlets and tidelands had lost a fraction of a point of pH, Feely told the shellfish farmers. The increase in acidity was simply a killer for embryonic oysters.

And that wasn’t Feely’s worst news. The seawater on the Pacific Coast cycles deep before rising to wash North America’s western shore. This is a slow process, which means that, even if carbon emissions were slashed that day, at least a generation would pass before the water would balance. Greater acidity, driven by the steady increases in carbon dioxide pollution, was yet to come. 

Bill Dewey, public policy director at Taylor Shellfish Farms, walked into the somber conference hall as Feely finished introducing the West Coast shellfish farmers to ocean acidification. A native New Englander drawn west by the University of Washington marine biology program, Dewey had spent decades advocating for Taylor Shellfish and the broader shellfish industry. He would later sit on a governor’s commission that drew up Washington’s acidification response and serve on the state board carrying that work forward. When Dewey heard Feely’s prognosis, he, like those who shared his muscular love of mollusks, felt broken.

“All these growers were walking around with their chins on the floor, like someone dear to them had just passed away,” said Dewey, whose employer operates one of the largest oyster hatcheries in the country and farms oysters, clams and mussels in Puget Sound and Willapa Bay.

“Dick had delivered this very sobering message about what was likely the culprit,” Dewey said. “Obviously, it’s nothing that growers could do anything about. It’s carbon pollution. … Even if by some miracle we can convince the rest of the world to stop burning fossil fuels, our problem is not going to get better for 30 to 50 years.”

The distraught sea people drifting through that high desert hotel could not know then what is clear now. Their response, amplified and carried forward by scientists and policy makers across the West Coast, would become a case study of hope in the face of environmental disaster.

The oyster growers and their allies could not decarbonize the world’s energy economy. What they could do, and what they have done, is innovate to solve the small problem — keeping the pH high enough for larvae to survive — and use their nightmare as a springboard for more ambitious fixes at the edge of humanity’s ability. Assisted evolution. Underwater forestry. Defenses for an entire ecosystem.

Ocean acidification impacts all invertebrates in Pacific Northwest waters. About one-third of the organisms living in Puget Sound, the estuary surrounding the Seattle metro area, build shells as oysters do. The shells of pteropods — tiny translucent sea snails that flit through the water on little fins and are a key food for salmon — are dissolving. Phytoplankton and abalone are struggling.

“If it is affecting the oysters that we’re growing, then it’s affecting everything else that’s trying to build a shell or a skeleton out there,” said Betsy Peabody, executive director of the Puget Sound Restoration Fund. “And if it starts to affect all the little guys, then it’s going to affect everything that eats the little guys. And so on, up the food chain.”


As chemical processes go, ocean acidification is simple. Carbon dioxide in the atmosphere is absorbed by seawater, lowering the water’s naturally basic pH of 8 closer to a neutral 7. 

“For a while people honestly thought, ‘Thank God, the oceans are absorbing 30% of carbon emissions. Otherwise, we would be in a whole world of hurt,’ ” Peabody said in a recent interview. “And then people started to realize that, ‘Holy shit, those CO2 emissions that are being absorbed into marine systems are of course having an effect on seawater chemistry and triggering chemical reactions.’ ”

And the effect is not small. Oceans are acidifying 10 times faster than any time in at least the past 50 million years. The rate of change is even greater in West Coast waters, particularly those in large estuaries like Puget Sound. A 0.1-point slide down the pH scale — the change that Earth’s oceans have already seen — represents a 30% increase in acidity. Estimates suggest that, unless global carbon dioxide emissions are cut, oceans will see a 150% increase in acidity by 2100. The last time ocean chemistry changed so rapidly, mammals replaced dinosaurs as the planet’s dominant fauna.

“We know enough now to know it’s going to be problematic, the degree to which it is hard to assess,” said George Waldbusser, associate professor of ocean ecology and biogeochemistry at Oregon State University. “Any period of time when we’ve changed the conditions on the planet as rapidly they are changing now, there’ve been mass extinction events.”

When water reacts with carbon dioxide, the process consumes carbonate ions in the water. Oyster shells are composed primarily of calcium carbonate, so when there are fewer carbonates in the surrounding waters, larvae must work harder to grow, or die before reaching maturity.

Research into acidification’s less obvious impacts is ongoing. There are indications, for instance, that low pH water may impair a neurotransmitter that enables animals to perceive their environments. What’s clear, though, is that acidification stresses species already burdened by pollution, rising water temperatures, overfishing and habitat loss.

Waldbusser, who helped identify the mechanism by which acidification kills Pacific oyster larvae, said it’s difficult to predict whether a particular species will adapt to the changing seawater — the systems are too complex to thoroughly model over generations, with the water’s end state unknown. Some species appear relatively resilient, while others are hamstrung by adaptations unsuited to an acidified ocean. As the growers learned a decade ago, Pacific oysters, the meaty staple of the Northwest shellfish industry, fall into the latter group.


Pacific oyster larvae build shell incredibly rapidly, covering themselves almost completely during a six-hour sprint. In low-carbonate waters, though, they run out of fuel before they can build an initial shell, then die. The impact was devastating at Northwest oyster hatcheries. At Oregon’s Whiskey Creek Shellfish Hatchery, for instance, production in 2008 was just 25% of normal. Research launched after the die-offs showed larval oysters surrounded by malformed shells, lumpy and disordered where they ought to carry concentric elegance.

With acidification’s role revealed, the rush was on to buy oyster larvae critical time. Researchers and oyster growers realized they only had to keep the pH up long enough for larvae to pass that crucial early window; after that, they could begin maturing in open-water beds.

At Oregon State, professor Burke Hales and his team crafted a sensor that could calculate carbonate chemistry in real time. Waldbusser said the sensor, first installed at Whiskey Creek in 2011, “put the headlights on for the industry.” With Hales’ machine, said Taylor Shellfish Farms' Dewey,  oyster growers began dodging bad water “so that our babies are able to build shells.”

Washington Sen. Maria Cantwell secured funding the following year to buy a clutch of the $50,000 machines known in the industry, with affection for their inventor, as “Burke-O-Lators.” Shellfish are big business in the Pacific Northwest, generating about $270 million in economic activity annually. Washington’s shellfish industry, which produces about three times the combined output of California and Oregon, also retains significant political sway. Unlike most of rural Washington, coastal areas tend to vote Democratic; the annual pilgrimage to Willapa Bay for a crab feed is required of party leaders in the state.

With the Burke-O-Lators installed, hatchery managers were able to avoid the worst water. They started drawing water to store for the larvae in the afternoon after photosynthesis had done its carbon dioxide-removing work. Treatment systems were built to pour soda ash into the hatchery water automatically when carbonate concentrations slipped. At the Whiskey Creek hatchery, managers watch the weather so they can store good water when shifts in the wind begin driving low pH water toward shore. 

And it worked. Hatcheries that had seen production fall by more than half had bounced back five years after the crisis. Techniques dashed together in response to the crisis have been adopted around the world.

“We fixed a chemistry problem in the hatcheries,” Waldbusser said, “and that saved the industry.”

Those taking on acidification draw on that success when steeling themselves for the larger task: saving what they can of the coastal seas.


Called together in 2012 by then-Washington Gov. Chris Gregoire, a collection of power players drawn from academia, the shellfish industry, conservation organizations and government turned out a 42-point plan to address ocean acidification in the state. “Let’s get to work,” Gregoire told an audience at the Seattle Aquarium as she announced the acidification task force’s recommendations in fall 2012. “Let’s lead the world in addressing this global challenge.”

That framework, since replicated in Oregon, Maryland, Maine and elsewhere, shapes a multimillion-dollar research and response effort.

“Early on, Gov. Gregoire was challenged as to what a small state like Washington, being such a small contributor to overall carbon pollution, could possibly do that will make a difference on ocean acidification,” Dewey said. “Her response was, ‘We can lead.’ ”

The scheme is comprehensive in scope, touching on everything from cutting locally generated pollution to laboratory research to education on ocean acidification. A network of buoys used to monitor ocean conditions off the Washington and Oregon coasts was retooled to forecast calcium carbonate levels. None of it solved the worsening pH problem in Puget Sound; rather, the effort’s aim was to blunt acidification’s worst blows.

Grand chemical interventions have been floated as an ecosystem-scale fix to acidification. Some proposed mining and dumping limestone into the ocean, but evaluations suggest the benefits would barely offset the emissions generated by the effort. Others thought the solution was held by shellfish themselves. “There was some hope that you could basically grind up shell, then sprinkle it like fairy dust around tide flats and all of a sudden they’d get better,” Waldbusser said. “But there’s an incredible amount of chemistry, physics and biogeochemistry that goes into actually doing that in a way that would make that effective.”

Many other efforts to address the problem are being tested in a hodgepodge of single-story pole buildings clustered at a little bay on Puget Sound’s western shore. Equal parts fishing village and moon base in appearance, the Kenneth K. Chew Center for Shellfish Research and Restoration is a collection of nearly windowless, slant-roofed rectangles surrounded by fiberglass tubs ranging in size from kitchen sink to whaleboat. The 5-year-old center’s graceless architecture speaks to its utilitarian heritage — it shares space at the National Oceanic and Atmospheric Administration’s Manchester Research Station, an aquaculture test bed built up in the 1970s — while underselling the pioneering science Puget Sound Restoration Fund biologists and others are building inside its beige walls.

Like most urbanized waterways, Puget Sound already saw its health faltering before acidification. Fertilizer runoff and sewage feed microscopic creatures that multiply and die, fouling the water further as they decompose. Habitat on both sides of the tide line suffers under pressure of the expanding human footprint.

Facing all of that, Peabody, the Puget Sound Restoration Fund founder, plans to build a forest underwater. Her team will plant bull kelp beds that boost the local pH and provide better conditions for shellfish. 

Bull kelp forests, lush vertical environments rich with marine life, once filled swaths of Puget Sound. The bull kelp were the patriarchs, their streamers building a canopy that extended from bulbous heads anchored to the seafloor. Smaller kelp species and red algae rose in the understory, filtering the water while drawing in sea urchin, crab, and other invertebrates.

“They’re one of the forests of this place,” Peabody said, her rubber boots crunching on the gravel paths connecting the Chew center labs. “Essentially, when you put bull kelp out into the marine system, you’re ringing the dinner bell and, you know, this is everybody’s favorite food. Yum-yum.”

Inside one low-slung building, biologists are growing a batch of bull kelp they plan to plant over the coming winter. Peabody wants to find a way to seed a critical mass of bull kelp so that the forest can sustain itself. Scientists working at the center are trying to dial in the timing and the technique. It’s a discovery process, said Peabody, the goal of which is wide phytoremediation — utilizing plants to clean up an ecosystem — around the Sound.

Puget Sound Restoration Fund kelp biologist Max Calloway’s aims are simpler — keep the nascent kelp alive, and himself sane. Almost invisible in its early stages, the kelp can get swamped by microalgae if its tanks are tainted. Scientists, too, can become overwhelmed.  

“I need to find a therapist, because working in this field at my age at this time in history is very depressing,” joked Calloway, 32, dressed in white, food-grade knee boots and matching lab coat. “The work that we’re doing is incredibly important — we’re developing the methods to reintroduce a lot of these species that are very critical to this marine environment. … But ocean temperatures are going to continue to rise, and the ocean is going to continue to acidify.”

Still, some biologists see bright spots. One native oyster species, for example, may yet thrive because of some biological luck. Olympia oysters flourished on the West Coast until the late 1800s, when excessive harvesting almost doomed them. Recent studies have shown that, because of a key difference in their reproductive process, Olympia larvae aren’t as susceptible to acidification while building their shells. Where Pacific oyster larvae grow their shells rapidly in the open water, Olympias mature more slowly inside their mothers’ shells for two weeks before they’re released.

Restoration fund biologists have planted Olympias on tidelands belonging to the Skokomish and Jamestown-S’Klallam tribes, and in a half-dozen bays around Puget Sound. They look for areas where the oysters might flourish, sometimes spreading oyster shell to create habitat, in the hope that the species will return to the ecosystem in force.

The Olympia oyster’s relative resilience, Waldbusser said, appears to be an “exaptation,” a bit of biology evolved for one purpose that happens to meet a new need. Brooding reproduction occurs in all sorts of environments, he said, and is not unique to low-pH waters like those on the West Coast. 

“As humans, we like this idea that nature is perfectly evolved,” Waldbusser said. “But nature is kind of sloppy, and that sloppiness or overhead is kind of a good thing. What you have is this sort of rapid evolution.”

Other scientists are working to help that evolution along themselves. In a cramped lab on the edge of the Manchester station, Jeremy Esposito and Kim Smith work on breeding shellfish that can take acidification’s hit.

Their employer, Pacific Hybreed, hopes to use gene sequencing to find and breed shellfish resistant to ocean acidification and disease. Esposito, a Long Island Sound oyster farmer turned biologist managing the little hatchery, and Smith, the production manager, look for survivors — oysters, scallops and other shellfish that show strong growth despite the water’s low pH — so geneticists at Pacific Hybreed’s California headquarters can isolate desirable genes. 

“We’ll say, ‘Look, this one has survived trials in the past, it’s offspring have survived trials in the past, so this must be the marker that shows resistance to ocean acidification or disease resistance,’” Esposito said.

Like other scientists studying the changing sea, Smith and Esposito work to address impacts of a problem they cannot solve. It is frustrating and fulfilling in, more or less, equal measure.  

“We can’t fix what’s going on in the oceans … so we’re trying to evolve beyond that curve and get ahead of it,” he said. “We saw some pretty low pHs, like 7.6, this summer. And that’s tough. That curve is just steep, and we see limited survival.”

“It makes it hard, when the pH drops super low,” said Smith, a constellation of near-microscopic Kumamoto oyster larvae she’d been measuring displayed on a computer monitor at her back. “You’re like, ‘Oh, God, how are these oysters going to survive?’”

Whether acidification will ultimately kill off the oysters or any West Coast sea creatures is anyone’s guess. No experiments conceived so far can show how quickly the organisms will acclimate to their changed and changing environment.

“Others have said this, but right now we’re doing the big experiment,” Waldbusser said. “We’re changing all these things and seeing the ocean respond. And the problem is, we don’t get the results of that until it’s too late. … But if history is any predictor, we’re certainly looking at a future that the ocean is going to look quite different.”


The shellfish industry is in for even more dramatic change. As the science progresses, indications are that ocean acidification’s toll on adult shellfish is substantial. Falling pH levels may one day make it impossible, or at least impractical, to plant and harvest oysters on tidelands that have so far been productive, Taylor Shellfish Farms' Dewey said.

He contemplates a time when oyster farms will be able to flourish only near eelgrass fields, as the biologically rich tidal meadows soak up carbon dioxide and stabilize the water. It would be a change, a difficult one, but the industry might survive. If it pains him to mull that future, he hides it well. 

“I remain optimistic,” Dewey said. “I kind of have to.”

He is an optimist in part because oyster growers and scientists fought ocean acidification and won — for now. He has to be an optimist because he loves the tidelands, their labors and their fruits.

Ensconced in a public affairs desk job in the late ’90s, Dewey bought some tideland on Samish Bay near Bellingham. The clam farm that started as a weekend hobby became, as Dewey described it, “not insignificant,” turning out 75,000 pounds of clams a year. He likes to run the math on how many plates he’s filled; at a half-pound of clams per meal, he has produced a couple million servings.

“I can go out, work hard on my farm, and at the end of the tide I can look back and say I just harvested 7,000 pounds of clams on a beach that, before I started farming it, produced nothing,” Dewey said. “Good, healthy food, growing a crop that is good for the ecosystem out there. … The shellfish farming is what keeps me going.”

After all, he said, this industry, and society as a whole, has over the years addressed many challenges. “If everyone works together, we can fix them. So I tend to remain optimistic. You just have to be optimistic there on the ocean acidification front, and keep pushing.”

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About the Authors & Contributors

Levi Pulkkinen

Levi Pulkkinen is a Seattle-based journalist specializing in law and justice issues in the Pacific Northwest.