Giant clams are slow growing and have a minimal defense system which makes them highly susceptible to any threat, whether from natural enemies or human threats such as unsustainable collection for seafood restaurants or the ornamental fish trade.

Giant clams are important biologically as well as economically. They work as marine filters as they take in harmful waste nutrients like ammonia and nitrate and expel clean water to the environment. The symbiotic zoothanthellae found within its mantel tissue produces oxygen during photosynthesis.

Unfortunately, every single part of these clams is of worth and in demand. The prized adductor muscle is much sought after by the dried seafood trade while the fresh mantle is sold in fish markets. Even its shells are sold as decorative souvenirs.

Despite all eight species of giant clams in the world being listed under Appendix II of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) which prohibits unrestricted trade between countries, giant clams are constantly found in seafood stores and prized in the ornamental fish trade. Giant clams are also listed as ‘Vulnerable’ in the IUCN Red List of Endangered Animals. These listings reflect the global concern regarding the possible extinction of giant clams as a whole.

Malaysia’s giant clams are fast disappearing. Two of Sabah’s seven wild species, including the biggest of them all, the Tridacna gigas (which can measure up to 4.6ft long) have been classified as ‘locally extinct’, the other being Tridacna derasa.

Protection of Giant Clams

Harvesting Giant Clams is a punishable offence under the Sabah Fishery Act, 1984. The act (of harvesting Giant Clams) has been equated to fish bombing whether committed inside or outside Sabah’s marine parks.