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Projects and Campaigns > Save the Drakes Bay Oyster Company > What Science Says About the Estero

What Science Says About Drakes Estero

The Point Reyes National Seashore Superintendent, staff, the Sierra Club and the Enviromental Action Committee have all made claims about the negative effects of oyster farming on Drakes Estero. To date all of these claims have been found to be false based on the National Park Service's own data.

Point Reyes National Seashore's own secret cameras show that the oyster farm is not harming the Harbor Seals.

Three days before the NPS first told the Marin County Board of Supervisors that the oyster farm was harming the seals, they secretly installed cameras to take a picture every minute of every day during pupping season. These 250,000 photos show that the seals are not bothered by the oyster workers, but by kayakers.

Oyster farming is NOT harming Harbor Seals.

Oyster farming is NOT harming eel grass or causing increased sedimentation in Drakes Estero

More Science

Drakes Estero at day break

Oysters = Good water quality:
        A single oyster can filter over fifty gallons of water per day. Scientists have found that the
shellfish aquaculture in Drakes Estero improves both species richness and abundance near the shellfish structures in Drakes Estero. Because of this, California State Legislation reads:


14950.   This chapter shall be known and may be cited as the Shellfish Protection Act of 1993.

14951.   The Legislature finds and declares all of the following:

   (a) Commercial shellfish harvesting is a beneficial use of the waters of the state and, in addition, benefits the economy of the state through the creation of jobs.
    (b) Pollution, from both point and nonpoint sources, currently threatens many of the state's commercial shellfish growing areas.
    (c) In order to maintain the health, and encourage the expansion, of commercial shellfish harvesting within the state , it is necessary to protect the commercial shellfish growing areas from ongoing point and nonpoint sources of pollution.
    (d) The regional boards whose jurisdictions include commercial shellfish growing areas shall have primary responsibility for the protection of commercial shellfish harvesting from the effects of point and nonpoint pollution sources.

Sampling data has shown that the water quality of Drakes Estero is actually improving. This improvement is likely due to the improved management practices performed by, and at the expense of the cattle ranchers located within Drakes Estero watershed. Thanks to their efforts, the Drakes Estero shellfish growing waters contain California's only "Approved" status growing area. Approved status means that there are no harvest closures due to potential pathogens in storm water runoff following rainfall, making Drakes Bay Oyster Company the only shellfish farm capable of harvesting every day of the year. All other growing areas of California are conditionally approved, requiring closures due to potential water quality impacts from runoff following significant rainfall. These mandatory closures can be very prolonged. Add to this that DBOC makes up over 50% of the shellfish growing area in California and you can see what losing the oyster farm would have a significant ecnomic impact.

Oysters don't threaten native species:
        Historically and currently, the shellfish species produced within this lease include Pacific Oysters, Kumamoto Oysters, Manila Clams and Purple Hinged Rock Scallops. These products continue to be produced as "singles" and sold live in-shell as well as shucked packed in various sized containers. The water temperature of Drakes Estero remains too cold for the non-native oysters to reproduce, therefore they are not able to escape into the natural habitat.
        The Drakes Bay Oyster Farm produces its own shellfish seed (baby shellfish) by performing remote setting on-farm, which mean no "hitchhiker" organisms or diseases are introduced from elsewhere.  


Copyright 2008, ALSA • P.O. Box 1316 • Pt. Reyes Station, CA 94956