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The Shellfish Aquaculture Industry and Tribes Are Good Neighbors

By Steve Robinson and Bob Vadas, Jr.

Is the shellfish industry a friend or foe when it comes to environmental restoration and protection? This is a controversial question, for which scientific reports provide support for both sides. Here, we respond to Laura Hendricks' winter 2010 Green Pages article on shellfish farming. We discuss the potential benefits of small- and large-scale industrial shellfish aquaculture.

Shellfish farming and enhancement not only provide an important food source in the South Sound, but they've proven to significantly clean up polluted water and provide much-needed habitat for other marine species. They're also vital to rural economies, as in southwestern Washington via recreational, commercial, and tribal shellfishing activities in Mason and Pacific counties. Recreational harvesting on South Sound beaches is a valuable tourist draw to our region, and dollars earned by tribal harvesters also circulate in the local economy.

Historically, the shellfish (from mussels to oysters) in the inlets of Puget Sound played an important role in the coastal ecosystems. This role, as long recognized by Billy Frank, Jr. (Nisqually tribal elder and veteran Chairman of the Northwest Indian Fisheries Commission), is filtering and cleaning water to enable the growth of healthy plant life, particularly eelgrass. Frank and marine scientists agree that for our subtidal zone to be healthy, the underwater "forest" must be lush with native seagrasses. But pollution and human-caused sedimentation have made much of Puget Sound's bottom barren. Two big steps toward recovering Puget Sound are to curb pollution and restore Nature's filtration systems by expanding shellfish aquaculture.

Farmed shellfish, i.e., oysters, mussels, and clams like geoducks, are bivalve mollusks with two-part shells that are each held together by a ligament hinge. They and their native counterparts are referred to as filter feeders because they feed by drawing water through their gills to filter out plankton (tiny plants and animals). This filtering improves water clarity and helps remove excess nitrogen (nutrients). Nutrients can cause algal blooms that contribute to low dissolved oxygen when they die. This results in fish kills such as those in southern Hood Canal. For this reason, shellfish farming can be a valuable tool to offset these human impacts.

Shellfish farming can cause some negative effects. These include interference with beachfront owners' views and public access due to the industry's tubes and nets. Geoducks are also harvested by pumping water into the sand around the clams to release them from the beds. Although it appears destructive, some research suggests otherwise. Scientists at the University of Washington (UW) and Canadian Department of Fisheries and Oceans have been studying the impacts of geoduck farming and harvesting for several years. Some studies show that shellfish farming apparently causes less ecologic than esthetic impacts. Some disturbances are a natural part of aquatic-ecosystem integrity, so allowing them helps to protect native biodiversity. This is similar to what has been learned about the role of fi res in forest and prairie ecosystems.

We believe that the environmental benefits of moderate-scale shellfish aquaculture far outweigh their negative impacts. By planting, seeding, and harvesting hundreds of thousands of shellfish every year, as well as by enhancing beaches and creating habitat for shellfish to flourish, the aquaculture industry contributes mightily to clean up Puget Sound. Shellfish farmers are also strong advocates for clean water, which is essential for farmed shellfish to be safe to consume.

We believe that the shellfish industry, which operates under local, state, and federal law and the principles of the Pacific Coast Shellfish Growers Association and its environmental-management system, is a good neighbor like the Tribes, who (a) retain the right to harvest shellfish via federal treaties and (b) have done much to recover shellfish populations. Both entities are significant contributors to the region's economy. Those who are serious about wanting to help restore Puget Sound should support carefully done shellfish aquaculture and the green economy that it's part of.

Many South Sound environmental organizations and the scientifically oriented American Fisheries Society now collaborate with the shellfish-farming industry. Achieving better state oversight, via legislative restoration of the Hydraulic Project Approval permitting process for tidal habitats, could help to reduce what fish and wildlife entrapments do occur from shellfish and coastal-land farming.

So tideland owners should consider shellfish gardening to aid Puget Sound's recovery. Perhaps local shellfish farmers and environmentalists could emulate estuarine-restoration partnerships elsewhere by obtaining funding to grow shellfishes in polluted waters, to help clean them up without having predation protectors or periodic harvesting. Indeed, we're all part of the problem and potential solution for the ecosystem health of Puget Sound. And the state's efforts to reduce shellfish overharvesting on beaches should also protect the important role of ecosystem filtering.

Steve Robinson is a SPEECH board member. Bob Vadas, Jr. is a state fish biologist and former SPEECH board member.

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Updated 2015/01/07 21:14:22