Can oyster farms make Puget Sound a little more wild?

Oysters were on the menu at the “Clean Oceans = Healthy Seafood” conference in Seattle last March, hosted by chefs Tom Douglas and Thierry Rautureau. But the briny bivalves weren’t dished out on the half-shell. They appeared in a slideshow presentation by Amy Van Saun, an attorney for the nonprofit Center for Food Safety.

Between photos of tractors on the sand and seemingly endless rows of plastic tubes along the shore used to grow geoduck, she noted that the number of shellfish farms in Puget Sound has expanded dramatically over the past few years — and she believes that’s a turn for the worse.

Part of this growth could be thanks to the Washington Shellfish Initiative, a government program launched in 2011. The initiative includes measures to protect and promote shellfish aquaculture, streamlining the permitting process for oyster farmers to make it easier for new growers. The state also hopes, by 2020, to reopen permanently 7,000 acres that traditionally have been used for recreational, commercial and subsistence shellfish harvests.

Some conservationists, like Van Saun, aren’t happy about further domesticating marine wilderness into commercial oyster operations. But oysters clean and filter water, and build reefs that can buffer climate-change-induced sea-level rise. Here in Washington, expanding oyster aquaculture may require us to restore parts of polluted Puget Sound.

Quasi-wild?

We like to think of oysters as “quasi-wild” — raised in seawater, filtering whatever phytoplankton comes through the bays and inlets. But oyster farming is a complex, highly engineered affair, a far cry from the natural resource harvest it once was.

“There is no baseline anymore, anywhere, for good, healthy, normal wild oysters,” says Alan Trimble, a University of Washington research ecologist who studies oysters in Willapa Bay. “We’re in a weird space. At some point we’re going to have to admit we’re actually farming.”

Farming, of course, entails changing the land (or sea) to better suit our needs. Expanding oyster farms “means the conversion of natural tidelands — and more of the cumulative impacts of farmed shellfish,” Van Saun says. Research suggests shellfish farming disrupts native species, such as eelgrass, in favor of non-native, farmed ones.

Van Saun and others argue that certain aspects of oyster farming in Washington are uniquely concerning. We’re the only state that ever has allowed use of pesticides on tide flats.

For decades, certain oyster growers in Willapa Bay used the insecticide carbaryl to attack ghost shrimp, which can decimate oyster beds. Carbaryl was disallowed in the early 2000s because it causes cancer.

In 2015 growers and environmental regulators reached an agreement to use a new pesticide, imidacloprid, a neonicotinoid that’s a known neurotoxin. Following backlash from the public and local chefs, the Department of Ecology rescinded the permit for imidacloprid in early 2016 but many growers feel a ban could mean the end of their oyster farms — and are trying again to get permits to use it.

A force for environmental good?

Not all oyster growers use pesticides and, in many ways, oyster farming could be a force for advancing environmental protection on the Sound.

Ironically, one main force holding back oyster aquaculture elsewhere in the state is land-based agriculture. The 7,000 acres the Washington Shellfish Initiative would like to restore to oyster cultivation includes about 4,000 acres in Samish Bay, south of Bellingham, much of it farmed by tribal groups. These acres historically have been farmed but currently are approved only conditionally for shellfish: when rain washes agricultural pollution into the bay, shellfish farmers can’t harvest. This runoff largely is from livestock manure and doesn’t impact just the oysters, but everything else living in Puget Sound.

“Agricultural pollution probably is one of the most significant challenges Puget Sound is facing today,” says environmental attorney Andrea Rodgers. It has been difficult to get livestock farmers to clean up their acts.

Cleaning up Samish Bay would require collaboration among local, state, federal and tribal partners, says Julie Horowitz, policy advisor for the Washington Shellfish Initiative. Such collaborations often are difficult to achieve. More than 20 groups have been working to clean the Samish watershed for years, and the Bay still failed the Department of Health’s pollution evaluation last year.

But Washington’s oyster growers are not ones to surrender to a challenge. They did, after all, figure out how to proliferate an animal that doesn’t reproduce naturally all that well in our waters. And the initiative already is making headway: Over the past four years, it opened 2,429 acres of commercial shellfish beds in south Puget Sound’s Oakland Bay that had been closed due to water quality.

So maybe the oyster is such a valuable food, and farming it such a cherished tradition, that it could rally efforts to reduce the pollution going into Puget Sound.

Samantha Larson is a Seattle-based freelance journalist and the science correspondent for Crosscut, where a version of this article originally appeared.