The San Francisco Chronicle gave front-page play the other day to a story about an oyster farmer in Drakes Bay and efforts by the Park Service to end his operations there by 2012.
    The reason? When Point Reyes National Seashore was authorized, it was understood that Drakes Bay would be returned to wilderness, according to seashore Superintendent Don Neubacher, and oyster farming is not compatible with wilderness.
    This story caught me a bit by surprise, because in the wake of my visit last fall to Tomales Bay, which also falls under the seashore's purview, I became interested in oyster research in those waters. Why, I wondered, are oysters not good in Drakes Bay, but good in Tomales Bay?
    The answer actually is quite simple.
    "In Tomales Bay we are referring to native oysters that create habitat for native species since they grow on the rocks in the intertidal zone of the bay," Dr. Ben Becker, a marine ecologist who oversees the Pacific Coast Science and Learning Center at the seashore, told me. "These native oysters are the ones that many would like to see restored to both Tomales and San Francisco bays since they were over-harvested during the last century and suffered from sedimentation and coastal development.
    "In contrast, the oysters being cultured in Drakes Estero (and Tomales Bay) for commercial purposes are non-native Pacific oysters that are generally grown off the bottom on racks and do not provide the same ecosystem benefits of native oysters.
     "But the greatest concern (as stated in the article) with oyster farming in Drakes Estero is that the Congress designated Drakes Estero to become wilderness in 2012, and to comply with the wilderness act there cannot be a commercial operation on site that cultivates shellfish."