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What's Killing the Bay Area's Oysters?

Signifiers of the good life, local bivalves may be harbingers of another phenomenon: species extinction.

Tomales Bay's finest.

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Saltwater tanks are home to billions of oyster larvae at the Whiskey Creek Shellfish Hatchery.

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Beakers full of algae used to feed the oysters at Whiskey Creek.

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It’s not even noon on the Fourth of July, but the restaurant at Tomales Bay Oyster Company in Marshall is already packed. Over 100 cars line the shoulder of Highway 1, while valets help another hundred find parking in a gravel lot. Every one of the 84 bayside picnic tables and charcoal grills is occupied, and even more customers spill onto the grass and benches nearby. The air is thick with music, conversation, and the salty scent of grilling shellfish. It’s a quintessential Bay Area scene, perhaps even a rite of passage—eating oysters is the local equivalent of feasting on lobsters in Maine or scarfing jambalaya in New Orleans. On weekends like this, local oyster farms Tomales Bay Oyster Company and Hog Island Oyster Company serve up nearly 200,000 of the tasty bivalves. And that’s chump change when compared to the roughly 7 million oysters that the five oyster farms on Tomales Bay sell each year to local restaurants and bars.

By the look of this scene, business is booming. But beneath the prosperous veneer, farmers are scrambling to keep the oysters coming—and worrying that in the not-too-distant future they may not harvest any at all. On busy weekends, Hog Island and Tomales Bay are forced to ship in oysters from other local farms, Washington State, and even the East Coast just to keep up with demand, a practice that comes with a hefty price tag. “It costs half a million per year to import those extra 700,000 or 800,000,” says Charles “Tod” Friend, owner of Tomales Bay Oyster Company. Before 2003, Hog Island’s farm, just up the road, had an average annual inventory of about 4 million oysters, but that year those numbers plummeted to 1.5 to 2 million and remained precariously low for almost a decade. Though Hog Island’s inventory had restabilized by 2013, the work required to get there was tremendous, says co-owner Terry Sawyer. “We’ve had to cut out so many of our customers, especially on the restaurant and wholesale side. We just couldn’t supply the product. It was painful—and still is because we’re not over it.”

The culprit? Ocean acidification—climate change’s caustic cousin—caused by rising carbon dioxide emissions. Over the last 10 years, it has wreaked havoc on the West Coast oyster business. And though farmers have found ways to work around it temporarily, the problem—both for oyster farming and for our coastal ecosystems—is only going to get worse. “I was once thinking I’d leave the farm to the kids, but now I don’t think there’s going to be a farm to leave,” says Friend. “Our days are numbered.”

 

Oysters have always had an intrinsic role in the Bay Area gastronomic culture. They served as a major food source for the Ohlone tribes and early pioneers. And when the gold rush struck, booming San Francisco had such a voracious appetite for the shellfish that the native Olympia species was nearly wiped out. By 1851, Californians had begun to replace wild harvests with commercial farming, which continues today. Much like terrestrial farmers, growers buy tiny “seed” oysters from hatcheries and “plant” them in sheltered coves and bays.

During the 1800s, California was the largest farmed-oyster producer on the West Coast, with San Francisco and Tomales Bays as its major production centers. Today the state’s production is dwarfed by that of Pacific Northwest growers, but five oyster farms remain in our local waters: Hog Island, Tomales Bay, Cove Mussel Company, Point Reyes Oyster Company, and Marin Oyster Company, all located in Tomales Bay. All of them sell wholesale to restaurants, and Hog Island, Point Reyes, and Tomales Bay also sell directly to the public at bayside picnic restaurants or retail stores.

Across the Point Reyes peninsula, Drakes Bay Oyster Company has been making headlines lately for its legal battle to remain in business after its National Park Service landlord declined to renew its lease. Its pending closure is a heavy blow to the local oyster economy. The 80-year-old farm had been the region’s largest oyster producer—in 2013, it yielded 8 million oysters—and the state’s only oyster cannery, and it also functioned as a local supplier. Tomales Bay Oyster Company alone received shipments of 6,000 to 15,000 oysters a week from Drakes. But Drakes’ legal woes were not the cause of the industry’s current crisis. For that, you have to dive deeper.

 

The Whiskey Creek shellfish hatchery in Tillamook, Oregon, looks more like a mad scientist’s experiment than a nursery: A series of mazelike rooms house gigantic vats of saltwater taller than a man’s head; illuminated walls glow behind jars and beakers of bubbling fluids; murky sunlight pours in through the clear plastic roof; and voices are drowned out by the overwhelming hum of machinery—all for what looks to be muddy water. To actually see the product of all this effort, you need a microscope.

Under the lens, miniscule, semitransparent spheres spin and swirl. These are larval oysters—just one millimeter across. The hatchery nurtures huge numbers of these youngsters through their first few weeks—in 2006, it sold roughly 10 billion of the tiny bivalves. When hardy enough, they are shipped out to growers around the Pacific, either directly to farmers or to middlemen who continue to grow the larvae into seed. Many ultimately wind up in Tomales Bay, destined to feed the Bay Area’s gastronomes.

But in 2007, catastrophe struck at Whiskey Creek. “There was a single day when pretty much everything was dead,” says hatchery manager Alan Barton. “We lost billions of billions of larvae.” The hatchery staff hoped that it was a fluke—after all, some mortality is normal. But the problem continued day after day, week after week. Soon an entire year had passed with an average survival rate of 25 percent. “We’d done everything that we knew how to do, and nothing worked,” says hatchery owner Sue Cudd. “I pretty much thought I was out of business.”

The problem was not confined to Whiskey Creek. In 2005, the National Oceanic and Atmospheric Administration began reporting that hatcheries throughout the West Coast were seeing steep declines in production, putting the $84 million industry in jeopardy. Hatchery staff and scientists scrambled to pinpoint the cause, and extensive water monitoring was carried out up and down the coast. Bacteria, pollution, and disease were all considered—and ruled out—as possible culprits. “We didn’t know what we were dealing with,” says Barton, who has a degree in oceanography. “Everything was dying. [We have] seen a lot of dead larvae, but this time the symptoms were really different.”

It wasn’t until a year later that Barton solved the mystery that had stumped scientists. On an ordinary summer day that was marred by a particularly bad die-off, he decided to test the pH levels in the tanks. “We use pH meters here every day to grow algae; it was really dumb of us not to think of sticking one in a tank,” he explains. Acidity constantly fluctuates, so it had never been considered a possible culprit. “You just have to get beat over the head with [information],” Barton says, “until you finally realize what’s going on, until the light comes on.” Lo and behold, the pH level of the water was drastically lower (read: more corrosive) than usual.

Ocean acidification isn’t a new problem. We’ve been hearing about it for decades, mainly in reference to the collapse of coral reefs around the globe. But because the acidification is exacerbated by carbon dioxide emissions, every year it gets a little worse. Since the first industrial revolution, humans have released roughly 550 billion metric tons of carbon dioxide into the atmosphere. These days, we release roughly 70 million tons per day—and the oceans soak up nearly a third of that. The result? On average, the sea is 30 percent more acidic than it was 200 years ago. And in the last decade, it began passing the point where young oysters can survive.

It’s not necessarily the acidity that causes problems for the oysters, but rather the concomitant lack of carbonate ions in the water. Shellfish use these free-floating ions to build their shells. When seawater absorbs carbon dioxide, the number of carbonate ions available for the shellfish is reduced. “A baby oyster is trying to eat, grow, move around, and make a shell. So if it spends more energy trying to make a shell, then something else in that equation is going to suffer,” says Tessa Hill, a scientist with UC Davis who studies the impacts of rising carbon dioxide levels on native shellfish. “I say it’s like balancing your checkbook—you can’t spend a lot of energy on one thing without cutting back in some other category.”

Here on the West Coast, we have some of the most corrosive seawater in the world, thanks to a natural process called upwelling. Upwelling occurs when strong wind patterns cause water from the deep ocean to resurface along our shores, usually during the spring and summer. This water is always more acidic than surface water—it has spent 30 to 50 years in the ocean interior, absorbing carbon dioxide from everything that sinks and decomposes there. And today’s upwelled water carries the added legacy of higher acidity from carbon dioxide absorbed during the ’60s and ’70s, the last time the water was at the surface. As it returns to us now, it mixes with the more recently acidified surface water to create an extra-acidic oyster-killing brew. In the last 200 years, the pH of seawater worldwide has dropped from an average of 8.2 to an average of 8.1. But as of late, Barton has regularly recorded a pH of 7.6 at the hatchery and has seen it go even lower. A change in pH from 8.1 to 7.6 may not sound earthshaking, but that 0.5 pH drop indicates a 150 percent increase in acidity from the worldwide average—an increase that larval oysters are not equipped to handle.

Still, winds are erratic and ocean chemistry is complex. At the moment, dangerously high acidity in the area is intermittent, fluctuating with the currents, winter runoff, pollution, and daily shifts in salinity as the tides change the balance of freshwater and saltwater. Even sunlight has an impact—when water plants are photosynthesizing and absorbing carbon dioxide from the water, acidity temporarily declines, only to rise again at night. So an oyster larva’s chances of survival are a crapshoot: If it starts developing in a season when acidity is too high, it will either die or suffer a long-lasting decrease in vigor. But when acidity is lower, its odds of survival are much better.

For the young oysters in the vats at Whiskey Creek, Barton had an absurdly simple solution. As Cudd recalls, “He said, ‘Oh my god, if this is what the problem is, I knew how to fix it when I was 12.’” All he had to do was treat the vats like they were his childhood fish tanks by adding sodium carbonate, a strong basic powder, to buffer the pH levels. The next day, the oysters were healthy again.

 

However simple the solution may have seemed, this new knowledge translated to a steep learning curve for the oyster industry at large. Where West Coast hatcheries once simply pumped water directly from the ocean with nothing but a rough screen to keep out fish and algae, they must now subject that water to a barrage of tests and treatments, including buffering and aeration. “It’s costing more to raise a single oyster,” says Greg Dale, southwest operations manager for Coast Seafoods, which runs multiple farms and hatcheries from California to Washington. “The additional technology and monitoring we have to use all add up to additional expense.”

Until last year, many hatcheries and farms did not meet their desired production levels. Some failed to make a profit at all. Even after Whiskey Creek started testing and buffering its water in 2008, it produced only 25 percent of the 10 billion oyster seeds that it had typically sold. Last year was the first year since 2006 that production was high enough to actually make a profit. “We lost a tremendous amount of money,” says Barton, “and we’re still trying to crawl out of that hole.”

Oyster farms, in turn, have been at the mercy of how much seed the hatcheries are able to grow. “In the past, it was just a matter of [telling a hatchery] what I wanted, and we got it,” says Friend. “Now you have to get on a list and wait your turn, and even when you get some, the total numbers are reduced.” Moreover, the oyster seeds have been less healthy, so fewer survive to delicious adulthood. The overall affect has been a dramatic decline in marketable Bay Area–raised oysters. Retail sales helped sustain some of the farms through the crisis, but they all took a heavy hit. “[Having the retail operations] kind of pulled me through, until I got a little seed,” says Friend. “Things have gotten a little better, but we’re still fighting the same fight.”

Amid frustration and uncertainty about the future, Bay Area oyster farms are doing their best to adapt to the situation. Hog Island has taken a lead in outreach, education, and research on ocean acidification. In 2012, Hog Island partnered with the UC Davis Bodega Marine Lab to collect onsite data from sensors installed at the mouth of the farm’s seawater intake pipes, which monitor daily changes in temperature, salinity, oxygen, and pH. The staff has also campaigned legislators for greater research funding, served on scientific boards, hosted meetings for teachers and scientists, and participated in legislative workshops and symposia. It has taken a lot of unpaid time, Sawyer says, but he and co-owner John Finger believe that they are in a position to make a difference. “We have a reputation and a passion, and we want to follow through with that,” Sawyer says. “We are keeping our eye on the ball here while moving ahead as a business.” And they are covering their bases: Hog Island will open its own private hatchery on Humboldt Bay this fall. It’s an aspect of the business that they never intended to get into, but with the few existing hatcheries struggling to meet demand, it’s the only way to help ensure a constant supply. The hope is that the hatchery will free them from the ever-increasing competition for seed and also enable them to sell their excess to other farmers, alleviating the overall shortage.

In addition to the boost that Friend gained from his retail operations, he attributes much of his current stability to working with a local middleman: Starbird Mariculture. The company opened up shop in the early days of the seed crisis with a plan to stockpile seeds and sell them to local Tomales Bay growers as needed. “The people who sell the seed may have it today but not tomorrow,” says owner Chris Starbird. “If you can take it when they have it, then you’re at an advantage.” Starbird is able to reserve larger quantities of the available supply than the farmers could obtain on their own, and he only sells to those on Tomales Bay. “I’m trying to support the Tomales Bay oyster farmers,” Starbird says. “But they have a need that I haven’t been able to satisfy. They always want more.”

 

Back on the rocky shores of Tomales Bay, the cheerful picnickers are more or less oblivious to how much effort has gone into bringing them their tasty treats on the half shell. And no one knows how long they will be able to keep enjoying them. Oyster harvests are stable—at least for now—but growers and scientists alike are nervous about the future. Unless carbon emissions drop—a highly unlikely prospect—oyster farmers will remain locked in a battle pitting technological fixes against ever-increasing ocean acidity.

“These adaptation strategies we’ve developed are short-term; we’re going to have to develop better strategies,” says Richard Feely, an oceanographer and ocean acidification expert with the National Oceanic and Atmospheric Administration. Farmers’ speculations on what this will mean for them vary widely, but they all know that the current solutions are only temporary. “We’re getting better at treating the water and understanding what’s wrong with the water,” says Barton. “But I’m probably not ever going to be able to retire.” And conditions are projected to worsen: In just 15 years, high-acidity days will occur throughout most of the summer. By 2050, according to an article published in the highly regarded scientific journal Science, they are expected to persist year-round in many places along the West Coast.

And the West Coast oyster industry’s travails are a mere harbinger of things to come. According to Feely, oceans worldwide are eventually expected to be at least as acidic as our region is today. The same water that threatens our oysters Rockefeller is poised to upend intertidal ecology, and many wild shellfish, including clams, mussels, snails, and oysters, are threatened. Fewer will survive, and those that do will be smaller and weaker, with thinner shells that are more vulnerable to being crushed by waves or predators. “I’m not an expert,” says Friend. “But at a certain point, the ocean is not going to allow these shellfish to make shell. The extinction of most shellfish in the ocean, that’s the big picture.”

Of course, the Bay Area is known for innovation, and as long as farmers are willing to invest in developing new oyster-rearing technologies, we will probably be able to grow oysters for those who can afford them. Some industry experts have even suggested that oysters may come to be raised entirely in tanks, having no contact with the ocean at all. But how expensive, and how sustainable, would the shellfish be then? Moreover, what is an oyster that has never known the sea? Will some intrinsic flavor—something wild, salty, and ancient—be lost? And what will become of their wild cousins already on the verge of extinction? These are the questions that hover over the humming, bubbling tanks of the hatcheries, over the crushed-ice displays in city storefronts, and over the tables full of picnickers happily slinging back mollusk after mollusk on the shores of Tomales Bay.

 

Originally published in the September issue of San Francisco

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