Estrategias reproductivas de moluscos bivalvos y equinoideos

The theoretical aspects of reproductive strategies and life histories are analyzed. The gonadal structures and the main features of gametogenesis of bivalves and echinoids are described. Research on the reproductive characteristics and gametogenic cycles of the bivalve molluscs in the Argentinian littoral and the echinoid Loxechinus albus is reviewed. Special references to Mytilus edulis, Aulacomya ater, Brachidontes purpuratus, Aequipecten tehuelchus, Zygochlamys patagonica, Ostrea puelchana, Clausinella gayi, Protothaca antiqua, Eurhomalea exalbida and Mesodesma mactroides are made. Analysis of reproductive cycles includes histological and ponderal descriptions of gonadal variations. The main trend found is the partial and multiple spawning episodes. Sexual variations in dioecious and hermaphroditic species are discussed.