ABSTRACT
Seven species of tridacnid clams are found in shallow tropical Indo-Pacific waters, including the “giant clam” Tridacna gigas, the largest bivalve ever evolved. These clams are distinct from other species employed in mariculture endeavors in that the juveniles and adults live in symbiosis with, and derive nutrients from, single-celled dino-flagellates of the genus Symbiodinium, the same group of zooxanthellae that inhabit corals. The chapter reviews advances in the biological and technical aspects of mariculture of tridacnid clams. Giant clams will survive out of water for 4 to 5 h with no adverse effects and live intertidally with virtually no mortality. Clams less than 3 months old attach to the substrate via byssal threads and mucus but are also able to move about by means of a muscular foot and reattach to the substrate. Tridacnid clams are sequential simultaneous hermaphrodites, developing spermeries at a younger age than ovaries.
