Sexual reproduction of two intertidal sea anemones (Coelenteria: Actiniaria) in Malaysia

Abstract

Sexual reproduction in the actinians *Anthopleura handi* Dunn and *Haliplanella luciae* (Verrill) was studied through one year at Jeram, on the Malacca Straits. No evidence could be marshalled to support periodicity in gametogenesis of either species. The absence of cyclicity in prevalence and size of internally brooded young of *A. handi* substantiates this finding for the species. Female, sterile, and hermaphroditic anemones brood. The sex ratio of smaller individuals is heavily biased toward females; that of larger anemones is more balanced, suggesting that some but not all individuals are protogynous. Sterile and hermaphroditic brooders are inferred to be transitional from female (when the young are produced) to male (by which time all young have been released). Only sterile and female individuals of *H. luciae* were found. Although as many as half the anemones may bear eggs at any time, the absence of males presumably precludes sexual reproduction. Asexual reproduction by pedal laceration appears to be the sole means of progagation.