Oyster farmers are hard working people who know the water and know a lot about shellfish biology. Some farmers are even trained marine biologists!
Every farm is a reef and provides ecosystem services to the surrounding bay or estuary. Here's some background from Rowan Jacobsen's A Geography of Oysters about the limitations of California's natural ability to nurture oysters
"For a big state, California’s oyster industry is confined to a small area. Tomales Bay is the center of the action, with several small growers, including Hog Island. Coast Seafoods, the largest oyster company in the country, has major Kumamoto farms to the north in Humboldt Bay. Other than a handful of quixotic operations in Carlsbad, Santa Barbara, Morro Bay, and Drake’s Estero, that’s it. It’s all in the geography. California isn’t blessed with many bays. It has one world-class bay (San Francisco), and one dinky one (Humboldt). San Francisco Bay held billions of Olympia oysters in the 1850s, zero in the 1860s. By the time Pacific oyster seed was available from Japan, San Francisco Bay was far too polluted to grow oysters. Tomales Bay, the other workable water body, is a geological freak. When Point Reyes, the tomahawk-shaped wedge of land that is the tip of the Pacific Continental Plate, slammed into the rest of California, which edges the North American Continental Plate, it didn’t make a perfect fit. Tomales Bay is the imperfection, more a crevice than a typical bay."
Given our limited nurturing geology for nurturing oysters, it's high time to bring oysters back to the Bay. Oysters may be the word's most sustainable fishery! You don't have to feed or water them, they are quite low on the food chain, and their carbon footprint is practically nil - especially if the oysters you are eating are grown locally!