Should pesticide use be allowed in oyster beds?

Seattle Times food writer Bethany Jean Clement discusses the controversy over the use of imidacloprid in the aquafarming of oysters.

Mention pesticide use and most people think about sprays used on fields. But did you know that pesticides are sometimes used in aquafarming? Last April, amid bad publicity and public outcry, a proposal for pesticide use in southern Washington state was thwarted. A quarter of the nation’s oysters come from the beds in question in Willapa Bay and Grays Harbor. The controversy over whether to use pesticides in oyster production has reared up again. Seattle Times food writer Bethany Jean Clement made some time to help me make sense of the debate.

Oyster Beds - cbgrfx123
Oyster beds (Photo by cbgrfx123)

Evan: First let’s talk about the oysters beds. Are we talking about bags of oysters that are out in a cove or in a bay? Or are we talking about oysters that are near the beach on tidal flats?

Bethany: We are talking about the latter: oysters that are being grown by oyster farmers on the tide flats themselves.

Evan: Which pesticides are we talking about?

Bethany: Well, they use a pesticide to control a native species of burrowing shrimp and that began to proliferate in the 1960s and no one really knows why. So the solution of the day, back then, was pesticide. It was a different one at that time. And then that one was shown to be associated with cancer and was phased out under pressure from environmentalists. And then these growers had to put in an application to use a new pesticide, which is when all this sort of came to light.

Willapa Bay Oyster Beds by Sam Beebe
An aerial view of the Willapa Bay oyster beds in Washington. (Photo by Sam Beebe)

Evan: The pesticide in question now is imidacloprid, the one that is widely used on land crops and is famously associated with bee colonies collapsing. How does it work in the oyster beds?

Bethany: They spray it over the oyster beds and the imidacloprid would go down into the sand, and as I understand it, it paralyzes these burrowing shrimp and kills them, which then keeps them from digging around in the sand and creating a situation that’s very silty where the oysters sink down and suffocate. They are making the sand sort of soupy: where the oysters would normally lie on the top of the sand, they sort of descend into it and suffocate.

Evan: Do we know anything about the life of the pesticide in the water or the life of the pesticide on or in the oyster?

Bethany: The E.P.A. is currently in the process of assessing this pesticide’s impact on aquatic life. We won’t have their results until the end of this year. Not a great deal is known. I mean some would say that [when] a pesticide like this [is] sprayed on a tide flat, then the tide comes in and it dissipates in the water column. But a lot of bad things get dumped into the ocean. Does a pesticide need to be one of them? The chefs here in Seattle who found out about this plan were aghast and there was a huge public outcry.

Evan: There’s something about the pesticide being used near water and the fact that so many people are eating those oysters raw. Which companies want to use the pesticide?

Bethany: The companies have actually withdrawn their participation in this application after the gigantic public hue and cry about this use of neurotoxic pesticide on Washington state oyster beds.

Willapa Bay Oysters detail
Oysters growing in Willapa Bay. (Photo by Tara Schmidt)

Bethany: I spoke with the Washington state Department of Ecology and the application was turned in but it was not complete. So it has not actually even been officially turned in for consideration yet. And what they say is that when the application is turned in completed, the process will start to unfold. There will be public comment periods and they urge people to keep an eye out on their blog and they really want input from the public if and when the comment period comes to pass.

Evan: You’re a reporter and so you need to have objectivity. But what do you make of all this?

Bethany: Our reporters here at The Seattle Times spoke with one oyster farmer who is pursuing organic methods out in this same coastal area of Washington where pesticides have been used and she stopped her operation after she said she detected chemicals from neighboring operations in her own oyster beds. She just felt there was too much danger. I would also add — along the lines of my personal feelings — the National Marine Fisheries Service and the U.S. Fish and Wildlife Service have both raised concerns about this new neurotoxin and the potential harmful effects if we begin introducing it to these aquatic environments. And as you said, this area on the southwest coast of Washington produces about a quarter of all the oysters eaten in the United States. So the stakes are high both financially and potentially environmentally.

(Header photo of oysters being shucked by kslee)