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A water quality manager for the State of Washington Department of Ecology approved a ten-year Pollutant Discharge Permit for designated members of Willapa Grays Harbor Oyster Growers Association on April 16, 2015. The permit details a plan for annual aerial spraying of the neurotoxic pesticide Imidacloprid on oyster and clam beds to reduce damage caused by what are locally called "burrowing shrimp" (Westneat).

When there are too many burrows, the consistency of mud-flat mollusc beds becomes more soupy and oysters on the tide flats sink-in enough to die of suffocation.

  • The permit allows the pesticide treatment initially to 500 acres in Grays Harbor and 1500 acres in Willapa Bay,
  • specifies Sediment Impact Zones of 2500 acres and 7500 acres respectively,
  • and requires both pre-treatment data collection concerning species populations, and four post-treatment measures of the populations and pollutant discharge.
As this permit restricts its wildlife testing concerns to the quantitative "abundance and taxonomic richness" of molluscs, crustaceans, and Polychaeta (Sec.3), the implication is that 'the pest' interfering with oyster aquaculure is not a shrimp, but likely the marine annelid worm, Polychaeta alitta, also known as clam worm.


Apparently, some oyster growers were spraying a similar pesticide, Carbaryl, on their oyster beds ("Who'd have thunk it?"). Since that one was being taken off the market due to its dangerous toxicity, they began looking for a substitute (Westneat).

According to Bill Taylor, owner of Taylor Shellfish Inc. (Willapa Bay), which harvests the most oysters of any oyster grower in Washington, his company has worked with Dept. of Ecology on small-scale testing of the effectiveness and collateral damage of using Imidacloprid pesticide (Clement). Taylor Shellfish agreed in 2002 to phase out over a ten-year period its use of Carbaryl.

This new permit represents the next step in trying to reduce the problem -- by applying Imidacloprid, which is explictly not recommended for use on water, and is not used for this purpose anywhere else on the West Coast of the U.S. (Director of the Pacific Coast Shellfish Growers Assoc. cited by Clement). Most of the smaller-scale oyster growers (especially on Puget Sound and Hood Canal) have the common sense to resist any temptation to apply pesticide to their oyster plots (Lissa James cited by Clement).

What are These People Thinking?

After Danny Westneat's column Wednesday, April 29, in The Seattle Times publicized news of the Pollutant Discharge Permit, numerous restaurants in Seattle (including Bar Sajor, Cafe Presse, Le Pichet, Sitka & Spruce, and The Walrus and The Carpenter) have been scrambling for reassurance from their oyster suppliers that their restaurants will not be receiving oysters from Imidacloprid-treated oyster beds (Clement).

Taylor Shellfish received so many complaints from customers that Bill Taylor announced May 1 he has changed his mind and will not use Imidacloprid after all, although he remains convinced that oyster beds can be safely treated by aerial spraying of Imidacloprid (Garnick).

This oyster consumer is distressingly shocked that R. Doenges would approve the Dept. of Ecology permit. Its scope, while limited, ignores possibly fatal consequences to humans, birds, raccoons, fish, etc., and thus is inconsistent with my expectations for a Dept. of Ecology water quality manager. Imidacloprid does not seem appropriate for ingestion in any amount, and the permit allows for it to be sprayed on a food source! It is fairly well known in the Northwest that Imidacloprid has been scientifically implicated in bee colony collapse disorder. If it is truly in the "public interest" to attempt this project, as the Ecology permit states, we must only try it gradually, carefully testing a broader range of possible impacts with open minds. It definitely involves more than water quality.


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