With few significant rivers, and a hellacious multi-year drought that shows no signs of breaking, California oysters tend to be screamingly salty, as they grow in more or less pure ocean water. Tomales Bay and Humboldt Bay are the two main producing regions. Everything Tomales can grow (mostly Pacific oysters) gets sucked up by the Bay Area (which famously descends on the shores of Tomales Bay every weekend for extended oyster picnic mania), while Humboldt produces a lot of the country’s Kumamotos. A handful of boutique producers ply the waters farther south, primarily using suspended culture to compensate for the lack of bottom land. These oysters tend to have brittle but beautiful purple-black shells.