A Natural History of the Sand Dollar Encope Stokesi L. Agassiz in Panama

A population of the sand dollar Encope stokesi L. Agassiz was studied at Venado Beach on the Pacific coast of Panama during a 1-year period from July, 1973 through May, 1974. Intertidal distribution, abundance, and size structure of the population were examined. The species was restricted to the mid tidal level at Venado Beach. Density varied from a low of 19/m² to a high of 65/m². Recruitment of the population occurred the year round. Encope stokesi has a high growth rate, a low maximum size, and a short life expectancy of less than 1 year. Commensal relationships between Encope stokesi and species of the pinnotherid crab Dissodactylus are discussed.