Clams Everywhere

January 25, 2018

Question: What causes thousands and thousands of tiny clams to be left on shore at Newport Beach as far as the eye can see? This was Sunday, Jan. 14. Does this happen regularly, and if so, why? (Edwin Marcus)

Answer: Those appear to be bean clams (Donax gouldii). This is a Southern California clam species found on sandy shores from Point Conception to southern Baja. Bean clams are known for their large, observable population fluctuations. In fact, population surveys conducted by a researcher at Scripps Coastal Reserve from 1949 to 1952 showed densities peaking at 20,000 clams per square meter, while in years preceding and following this boon, densities fell below one clam per square meter. These population resurgences were found to occur every two to 14 years. Female bean clams reach sexual maturity after their first year and sometimes spawn more than once a year. They are broadcast spawners, producing up to 50,000 eggs each spawning event. They can reach a maximum length of one-and-a-half inches, and they can live up to three years.

Bean clams bury themselves in the sand, but when extreme low tide conditions combine with wind and swell, they can become exposed. The good news is that as long as the shells remain closed, they will likely survive and get pushed out to sea when the tide returns.

The time stamp on your photo shows that it was taken around 2 p.m. on Jan. 14. There was a low, minus tide at Newport Beach at that time, which would explain why so many were left exposed in the intertidal zone where they reside.

So do they taste good? I'm guessing a nice Clam Bean soup sounds good!