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Natural populations of global inshore fisheries are coming under heavy pressure, primarily due to overexploitation and habitat degradation. Stock enhancement of hatchery-reared seeds is perceived as an alternative strategy to enhance the regeneration process. The Aquaculture Department of the Southeast Asian Fisheries Development Center in the Philippines has been implementing activities related to stock enhancement of donkey's ear abalone (Haliotis asinina), mud crabs (Scylla spp.), giant clam (Tridacna gigas), and seahorses (Hippocampus spp.). Seed production techniques for abalone including a diet tagging method were established, and juvenile abalone were released and monitored in a marine protected area. Mud crabs conditioned before release had higher recapture rates compared to the non-conditioned crabs, which can be translated to higher survivorship. Giant clams stocked at 8-10 cm shell length have high survival 4 mo after stocking (90%), with initial mortalities occurring within the first few days due to transportation stress. Seed production trials for seahorse have begun. [ABSTRACT FROM AUTHOR]

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 20000 T. gigas were placed on coral reefs. In addition, >50000 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. [Copyright &y& Elsevier]