Giant clams are the largest of the marine bivalves and have been responsible for several important functions within a coral reef ecosystem. However, their persistence as a species has recently become threatened. The brightly colored tissue makes the giant clam highly desirable in the ornamental aquarium trade and very lucrative for aquarium poachers. Like corals, they share a symbiotic relationship with photosynthetic algal cells. The loss of clams from coral reef ecosystems is of grave concern as clams have significant positive effects on fish and invertebrate’s species richness and abundance. Presently, the giant clam, Tridacna derasa, is listed on the International Union for Conservation of Nature and Natural Resources Red List of Threatened Species as vulnerable.
Elton Nguyen, a fourth-year student studying evolution and ecology at OSU, is part of a small group of clam researchers from Indo-Pacific regions such as the Phillipines, Australia, and Palau, who are invested in conserving populations of the underappreciated giant clam species. This research is being conducted with the advice and collaboration of Dr. Andréa Grottoli (Professor, Earth Sciences), and with research support from CLSE’s lab preparator and research assistant, Carrington Conerly. Acquisition of clams was by Reef Systems Coral Farm/Biota Aquariums.
Giant clams have a high mortality rate from zygote to larvae, in addition to a relatively old age of maturity. Therefore, repopulation via natural sexual reproduction is simply not enough to keep the species prolific in their native waters. The proposed research uses an in vitro technique as a viable way to produce higher survivorship in the giant clam. The technique, although new to giant clams, has been used with other bivalves, and been demonstrated as an effective culture technique for endangered freshwater mussels. The in vitro culture techniques were developed in collaboration with Jacqualyn Halmbacher from The Columbus Zoo and Aquarium Freshwater Mussel Conservation and Research Center where freshwater culture techniques were transcribed for saltwater culture. This technique is performed under substantially more controlled laboratory conditions than traditional outdoor culture methods. Through the use of these in vitro culture techniques, researchers hope to develop methods to increase the giant clam species survivorship, in a way that is cost-efficient.