Abstract

Commercial clam landings reached an average of almost 91,000 tons annually in Chile over the last decade. In spite of the high value of this resource, few efforts have been made to understand the basic biology of the exploited species, data that might in the future be needed to aid in their protection or even artificial culture. This study is a contribution to the knowledge of the reproductive cycles of two valuable species, Semele solida (Gray) and Gari solida (Gray). Representative samples of these species were collected at two widely separated localities in Chile and examined histologically to determine their seasonal reproductive cycles. It was found that the species were of separate sexes, and had annual gonadal cycles. In S. solida from northern Chile, the reproductive period extended from June 1991 to February 1992. In G. solida from southern-central Chile, the reproductive period was relatively short, from October 1991 to February 1992. In both species, most specimens have empty gonads by March. The data obtained are useful in developing management plans related to their reproductive periods. Relevant to culture strategies, S. solida has the comparative advantage of a lengthy reproductive period, wherein mature individuals may be frequently encountered in nature for spawning inductions. G. solida, with its shorter annual reproductive cycle may have the advantage of being induced to mature in artificial conditioning systems over relatively short periods of time.