Richardson Bay functions as a nursery for San Francisco Bay's marine ecosystem. Its shallow waters warm faster than the deeper bay, supporting eelgrass beds that provide habitat for juvenile fish, invertebrates, and the Pacific herring that spawn here each winter. Migratory birds -- including diving ducks, cormorants, and shorebirds -- use the bay as a staging area along the Pacific Flyway. The Richardson Bay Audubon Center and Sanctuary, located on the Tiburon shoreline, protects a portion of the bay and its adjacent uplands as a nature preserve.

Richardson Bay has long been home to a community of people living on boats, both in organized marinas and as 'anchor-outs' -- vessels moored outside any marina without permits or services. The anchor-out community has been a source of controversy for decades, pitting housing advocates who see the boats as a last refuge for people priced out of Marin County against environmental regulators concerned about sewage discharge, abandoned vessels, and damage to the bay floor. The Richardson Bay Regional Agency has worked to reduce the number of anchor-outs and remove derelict vessels, a process that has displaced some residents while improving water quality.

Sea level rise poses a particular threat to Richardson Bay's ecology. Because the bay is so shallow, even modest increases in water level could alter the distribution of eelgrass beds and change the habitat conditions that support the bay's biological productivity. Shoreline development, stormwater runoff, and boat traffic add additional pressures. The joint powers agreement that governs the bay reflects an understanding that this body of water is too important and too fragile to be managed by any single jurisdiction. Richardson Bay's future depends on the same cooperative approach that has sustained it so far -- and on the recognition that the bay's ecological value exceeds any economic use of its shallow waters.