Thursday, July 26, 2018
Pesticide Not Needed For Oyster Production
There are alternatives to shrimp pesticide
Dear Editor Chinook Observer,
(Published Wednesday June 13, 2018, print edition.)
I am writing in response to the Science Conference report. The section on oysters reads more like marketing rhetoric for chemical companies than it does like actual oyster related facts.
The oysters most commonly grown in our bay now, are known as Pacific oysters and were originally from Japan. These oysters, like most oysters, are not adapted to living on mud. In their natural habitat they attach to hard clean surfaces. Off bottom culture is often ideal, to keep them off the mud; it has been practiced in many places around the world since at least the Roman Era.
Flip and tumble bag culture is nothing new. It is used on the East Coast of the US to produce the medium sized, premium, deep cupped and neat shelled oysters prized by the half-shell market. There are many other types of off bottom culture being used in the US and around the world. These techniques include tumble cages, stationary or removable tray culture with substantial supports, and floating systems.
In many areas of our East and Gulf Coasts, oyster reefs are being reestablished. They rely on a variety of structural supports including pyramids or berms made of bagged or caged oyster shells. They can also include recycled concrete. Seeding of oysters on to these structures relies on natural sources or hatchery larvae. In some areas the restored reefs have existed long enough for oysters to be harvested. Our native Olympia oysters originally grew on oyster reefs, which kept them out of the mud, out of conflict with burrowing shrimp, and provided overall ecosystem benefits as well.
Burrowing shrimp, by the way, are not an invasive species. They are native to our area. They are an important environmental keystone species, providing ecosystem benefits, and they existed here for millions of years alongside our native oysters. Burrowing shrimp are repelled by eelgrass.
Destruction of eelgrass beds is on-going in our bay by the intentional use of herbicides. It is also well documented that human caused impacts to the ecosystem have severely reduced burrowing shrimp predators, and changed the ecology in other ways that benefit some species of burrowing shrimp. Meanwhile, other species of burrowing shrimp are now threatened by an invasive non-native parasite. There is concern that the affected species may not survive.
Imidacloprid is a neonicotinoid insecticide that has recently been banned for all outdoor use in most member states of the European Union, because of devastating ecosystem effects and negative health effects on human beings. The very same salmon mentioned in another part of the article depend on tiny creatures in our bay to reach a healthy size before entering the ocean. Imidacloprid spread or sprayed in our bay will further negatively affect our salmon runs by killing the food they depend on. Many other species depend on the creatures that would be killed by imidacloprid, including our endangered sturgeon. And imidacloprid is directly toxic to arthropods of commercial interest, namely our market shrimp and crabs.
The Willapa Grays Harbor Oyster Growers Association is the only oyster growers association in the US which wishes to use this deadly ecosystem toxin in coastal waters. The much larger Pacific Coast Shellfish Growers Association has publicly repudiated the idea. Please do not forget that oysters are filter feeders and that if you eat our local oysters you are eating everything that gets dumped into our bay.
The Department of Ecology made the right decision, based on peer reviewed scientific studies and reports. For more information on the science please visit the Facebook group, Resisting Toxics in CoastalEnvironments.