The status of tridacnid clam resources in the Indo-Pacific region and studies of their basic biology and ecology, including life histories, growth rates and phototrophic capabilities, spawning induction and larval and juvenile rearing are reviewed. They are the only phototrophic potential farm animals known to mankind. It is concluded that large-scale extensive mariculture operations are now technically feasible and could make a major contribution to theeconomies of Indo-Pacific countries, particularly the island states. The possibility of introducing tridacnid clams to parts of the Indo-Pacific outside their present ranges and to the Caribbean Sea should be seriously considered. Tridacna gigas is currently being re-introduced to Guam where the species has undergone recent extinction.