Why are there sand dollars on some beaches and not others?

Question

Why are there sand dollars on some beaches and not others?

Answer 1

According to the Monterey Aquarium sand dollars are found along the entire coast from Alaska to Baja California. All the other sites say they live slightly buried in the sand in coastal waters. This leads me to believe that they are there on any sandy beach.

It was suggested if one is trying to find sand dollars, comb the beaches as the tide recedes. The best time for collecting is after a heavy storm, as many of the shells that have died are washed onto shore.

Obviously water temperature has nothing to do with it since they are found in Alaska as well as the southern areas. These area have both warm and cold water currents.