OLYMPIA — Local shellfish growers suffered a setback on Sept. 27, when the Washington Department of Ecology finalized denial of a permit to use a pesticide that kills destructive shrimp species. The agency cited growing concern over the chemical’s long-term effects.
In a stinging press release, a public relations company that represents the Willapa Grays Harbor Oyster Growers Association called DOE’s decision “blatantly political.” Oyster growers have vowed to appeal the decision.
Shellfish growers have increasingly struggled with ghost shrimp and mud shrimp, collectively known as “burrowing shrimp.” The animals burrow into oyster beds, making the bottom of the Willapa Bay so soft that shellfish cannot survive. Local growers say nothing but spraying the nicotine-derived pesticide imidacloprid on their beds will get the shrimp under control. They fear their industry, which provides around 2,000 jobs, could die if they don’t start spraying soon. The growers estimate that, without imidacloprid, they will lose almost $50 million to the shrimp by 2022.
The association’s original imidacloprid permit, granted in April 2015, caused such an uproar among environmentalists and seafood connoisseurs that the growers withdrew it. The association began the permit application process again in April 2017, asking to spray just 500 acres instead of the 2,000 acres allowed in the original permit.
This April, DOE officials issued a tentative denial, saying the proposal submitted by the association did not meet Washington’s sediment and water quality laws. A 30-day public comment period followed, but didn’t change the outcome. Citing newer research, agency officials concluded that use of the chemical could cause permanent harm to the bay’s ecosystem.
Growers are frustrated DOE waited months to formalize what feels to them like a foregone conclusion, Kathleen Nisbet of Goose Point Oysters said on Sept. 28. She, like many of her fellow farmers, thinks the agency caved to political pressure from urban groups that oppose the use of chemicals without really understanding how they affect the economy or environment.
“Seattle communities don’t understand how rural communities work. They could care less about jobs in our part of the state,” Nisbet said. “It’s really sad to see that it’s gotten this far on an issue that is so important for our community.”
For decades, shellfish growers used an insecticide called carbaryl to control burrowing shrimp. However, growing concerns about its safety led to tougher regulations. In 2015, DOE terminated the local growers’ carbaryl permit.
Researchers began studying imidacloprid as a possible replacement in the mid-1990s. Shellfish farmers hoped the new chemical would save their crops. They claim the amounts of imidacloprid they’d use would dissipate quickly, with little or no lasting impact on the bay.
“This is something that has been blown way out of proportion. You drink more neurotoxins in a cup of coffee than we put on an acre of tidelands,” Nisbet said. However, conservation groups and DOE scientists argue that there is a growing body of new evidence that imidacloprid is more harmful than previously thought.
According to the Final Environmental Impact Statement published by DOE, imidacloprid could persist in sediment and poison benthic invertebrates — the tiny animals that live at the very bottom of the bay. That, in turn, could eliminate an important source of food for birds and fish, the report said. Even relatively low concentrations could harm worms and crustaceans, with especially harmful consequences for Dungeness crabs.
“Even at very low levels, it was causing these acute or chronic impacts to critters,” said Rich Doenges, a scientist who oversees water quality-related projects, including the imidacloprid permit application, at DOE.
Imidacloprid is “highly toxic to aquatic invertebrates” and “extremely toxic to bees exposed either directly or through residues…” according to its Material Safety Data Sheet, a neutral source of information about the chemical’s environmental and health impacts.
While bees are fairly unlikely to come into contact with imidacloprid sprayed in the middle of the bay, scientists are concerned about any potential for exposure because bees have been vanishing in recent years.
Continued die-offs could have serious implications for humans. Several new studies that cite imidacloprid as a threat to bees and aquatic insects “led to a re-examination of both its costs and benefits,” according to DOE.
The agency noted that environmental and health agencies around the world are pushing for tougher regulations. In April 2018, the European Union voted to ban imidacloprid. The Canadian government also wants to phase out all agricultural and most other outdoor uses of the pesticide over the next three to five years.
According to Doenges, the mounting concern over honeybee health is one of the main reasons that so much new research about imidacloprid has emerged since the shellfish growers first sought a permit several years ago.
The Oyster Growers Association fired back, accusing DOE of “hiding behind” policy decisions in Canada and Europe.
Dr. Jeff Barrett, an environmental consultant who worked with both growers and DOE, thinks DOE unfairly interpreted crab-related research. In 2014, DOE asked local oystering expert Dr. Kim Patten to spray a 90-acre plot and see how it affected crabs. Patten concluded the chemical paralyzed or killed relatively few crabs, but DOE drew different conclusions due to an issue with the way Patten took his samples.
Because it was difficult to access the interior parts of the plot, Patten’s team “only walked the outside edge,” Barrett said, noting that most of the crabs on the plot were concentrated in the deep areas along the perimeter. By Patten’s calculations, the 147 damaged or dead crabs they found worked out to an average of about two or three crabs per acre, some of which were killed when researchers ran over them with quads. DOE, however, interpreted Patten’s data as representative of the mortality rates everywhere in the plot.
Doenges, the DOE scientist, says his team correctly interpreted the data. He pointed out that the dead crabs at the edge of Patten’s experimental plot were probably exposed to less imidacloprid than the crabs in the center that weren’t sampled.
“We saw that data as being persuasive that imidacloprid was indeed toxic to crabs,” Doenges said. “That was kind of supported by other studies.”
DOE also cited a study in which scientists exposed a species of blue crab to large quantities of the pesticide with catastrophic results. When the same researchers exposed crabs to the diluted commercial form similar to what local growers would use, the mortality rate was 20 to 30 times lower. According to Barrett, DOE focused on the effects of pure imidacloprid. Doenges noted that researchers decided to do the blue crab study after imidacloprid-laced agricultural runoff started killing crabs in a particular estuary, meaning that the study only confirmed a phenomenon they were already observing in real life.
“They are cherry-picking the data and misrepresenting it. We’ve told them that repeatedly,” Barrett said. In his opinion, DOE is missing the bigger point — without intervention, the shrimp will create a habitat that is even more hostile to crabs.
“When you have a whole bunch of burrowing shrimp, you don’t have much of anything else,” Barrett said.
Doenges doesn’t agree with their claims that using the chemical will make the bay more hospitable to other species.
“I don’t see how applying a pesticide on hundreds of acres is going to be better for the bay,” Doenges said. He said burrowing shrimp are a native species, and their populations have historically risen and fallen in response to various factors. One possible reason they’re so plentiful right now is that some of their natural predators, such as salmon and sturgeon, are not as abundant as they once were.
“I don’t agree with the statement that denying the permit is causing a disruption to the bay ecosystem,” Doenges said.
The growers have 30 days to appeal the decision to the Washington State Pollution Control Hearings Board. They plan to appeal, but they’re not especially optimistic, Nisbet said. In the meantime, growers are confronting the possibility that, with no other viable solutions in view, the industry may face some dramatic changes. According to Nisbet, oyster farmers operate on a three- to four-year crop rotation cycle. Farmers nearing the end of their current crop cycles fear the burrowing shrimp damage is so extensive that they won’t be able to set a new crop.
“I wish Seattle would understand that we’re not putting this on oysters and we’re not doing this to harm the environment. We’re doing this to treat a pest that takes over the environment,” Nisbet said. “That’s what we’re fighting for.”