PISMO BEACH, Calif. — Pismo Beach loved its clams. More than a century ago, farmers with horse-drawn plows would comb the sand and haul the clams off by the wagon-full. The meat was fed to the hogs.

Clams can once again be found at Pismo Beach, but not of a size that can be legally harvested. Cal Poly researchers are studying the population of the clams, which vary in shell color and pattern.