About Donax gouldii Dall, 1921
Commonly known as the bean clam, Donax gouldii Dall, 1921 may reach up to one inch in length. It has variable coloration, most often cream, buff, orange or blue, and frequently has darker rays extending outward from its hinge area. Its shells are relatively thick, wedge-shaped, and covered by a polished periostracum. When exposed by receding waves, the clam uses its muscular foot to rapidly dig back into the sand. The hydroid Eucheilota bakeri, often called the bean clam hydroid, is frequently found attached to the posterior end of the bean clam’s shell. This species has a lifespan of 1–3 years. Local populations experience distinct cycles of rapid population growth followed by mass die-offs: a population with a density of 20,000 clams per square meter can drop to fewer than a dozen individuals within a single year. These die-offs are hypothesized to be caused by mass infection from a parasitic microorganism similar to Perkinsus marinus, a pathogen known to disrupt oyster farming in the Gulf of Mexico and other areas along the southeastern coast of the United States. The bean clam’s range extends from Pismo Beach, California, to Arroyo del Conejo, Baja California Sur. It lives on exposed sandy shores, occurring from the mid-intertidal zone down to waters up to 30 meters deep. It often grows in large numbers at locations including Redondo Beach, California, and Newport Beach, California.
