Giant clam hatchery, ocean nursery and stock enhancement

A 109-page manual discusses the hatchery, ocean nursery and stock enhancement of giant clam. It also contains information on macroalgal and zooxanthellae culture.This manual is meant to serve as a guide to the culture of giant clams (Bivalvia, Subfamily Tridacninae). The first part focuses on hatchery methods. The second part is about the ocean nursery. The first two sections refer to selection and setting the ocean nursery site. Clam transport is introduced next although this is further tackled in the last part of this manual. Finally, the third and last part discusses the purposes of stock enhancement, survey methods for stock assessment, transport, monitoring and record keeping.The authors thank the Australian Centre for International Agricultural Research (ACIAR), International Center for Living Aquatic Resources Management (ICLARM, now WorldFish Center), International Development Research Centre (IDRC-Canada), Pew Fellows Program in Marine Conservation, Philippine Council for Aquatic and Marine Research and Development, and the University of the Philippines (UP) for financially supporting the MSI Giant Clam Program on Research, Mariculture, and Restocking

Achievements and lessons learned in restocking giant clams

Abstract For almost 20 years, the Marine Science Institute (MSI), University of the Philippines, has been culturing giant clams to restore depleted populations of these large bivalves in the Philippines, and to promote giant clam farming as a sustainable livelihood. Restocking activities were done in collaboration with local groups by providing training in the culture and ocean rearing of giant clams, and by implementing a "users pay" approach. Initially, a variety of giant clam species was used but once F1 broodstock of Tridacna gigas were reared, restocking focused on this species due to its scarcity and fast rate of growth. About 20 000 T. gigas were placed on coral reefs. In addition, >50 000 clams (T. gigas, T. squamosa, T. derasa, T. crocea, T. maxima and Hippopus hippopus) were distributed through other means. Altogether, >40 sites throughout the Philippines received cultured giant clams. Grow-out trials to test the viability of supplying giant clams for the aquarium trade to create new sources of income were conducted successfully with a group of fishers in Bolinao, Pangasinan. However, this initiative encountered legal obstacles when the government regulatory agency prohibited the export of cultured clams, regarding this as a threat to the conservation of wild individuals. The long experience in culturing and restocking giant clams in the Philippines provides many lessons for other countries wishing to restore stocks of these large bivalves. Particular care needs to be given to selection of release sites, negotiations with participating groups to safeguard the released clams, adequate transfer of technology to collaborators, and transport of large clams from nursery areas to release sites

Induction of Symbiosis in Tridacna crocea (C. Bivalvia, F. Tridacnidae) Using Zooxanthellae from T. gigas and from T. crocea: Effects on Clam Survival and Growth

Survival and growth of post-metamorphic Tridacna crocea juveniles were improved by inducing symbiosis with fresh or cloned zooxanthellae (Tg10) derived from T. gigas. Although clam growth was best with Tc4, survival was also poorest. Symbiosis with specific zooxanthellae was established at the pediveliger stage, with reinfection a few days after. It is suggested that while survival and growth may be easily monitored and may be used as indicators of good performance of a functional holobiont, other phenotypic traits such as resistance to disease, bleaching, etc. may also be considered in evaluating the effectivity of the selected zooxanthellae

Achievements and lessons learned in restocking giant clams in the Philippines

Restocking activities were done in collaboration with local groups by providing training in the culture and ocean-rearing of giant clams. Community involvement is critical to overcome multiple sources of mortality for giant clams, including poaching, predation, fouling of cages, typhoons and water temperature anomalies. Particular care needs to be given to selection of release sites, adequate transfer of technology to collaborators, and transport of large clams from nursery areas to release sites. 46 cohorts of giant clams have been cultured by Marine Science Institute (MSI) of the University of the Philippines-Diliman

Polymorphism and crypsis in the boring giant clam (Tridacna crocea): Potential strategies against visual predators

10.1007/s10750-009-9859-9Hydrobiologia635137-43HYDR