Giant clams, or Tridacninae, are a taxonomic subfamily of very large saltwater bi-valve molluscs. The largest of all, sometimes called the true giant clam (Tridacna gigas), grows to more than 1.2 meters across and 250 kilograms in weight, and lives for more than a century.
They also benefit any coral reef where they live since they serve as natural biological filters that help maintain an optimum nutrient balance in the water.
However, they all but disappeared from Philippine waters due to overharvesting for food, their shells and the aquarium trade.
With the help of Bolinao Marine Laboratory in Pangasinan, Biri Initiative plans to seed the reef around Biri Island with juveniles of indigenous species such as the southern giant clam (Tridacna derasa).
This is both challenging and costly, however. Clams are bred and raised in nurseries on land until they are two years old and 20 cm across, at which time they are large enough to place in the ocean. They are then carefully packaged and sent by air freight to their final destination. But even then, they must spend the next few years in steel cages to protect them from predators.
"Taclobo" a magnet for fish in Bohol. Philippine Daily Inquirer, Mar. 8, 2013.