Giant clams released into the wild in the Philippines
June 2008 - Philippines. A fresh batch of 40 True Giant Clams (Tridacna gigas) have just completed the journey from rearing laboratories in Bolinao to their new homes on Santelmo Reef.
Santelmo Reef is the Hamilo Coast's prized snorkelling site. An area once blasted by dynamite fishers, it has, with help from WWF -been regenerating for several years. Here new corals sprout alongside giant Porites boulders encrusted with legions of Christmas tree worms. WWF-Project Manager Paolo Pagaduan says "It's amazing how fast Santelmo's fauna has returned. Corals, invertebrates and even large reef fish are being seen more frequently."
102 True Giant Clams have already been planted 80 metres off Pico de Loro Cove last November. With an additional 35 underway, Hamilo's True Giant Clam population will exceed 170. "It is hoped that baby clam recruits will eventually appear to seed outlying areas in Batangas." adds Pagaduan.
The True Giant Clam - can exceed 5 feet
The True Giant Clam, described by Linnaeus in 1758, is the world's largest bivalve mollusc. It is the most massive of the seven known giant clam species and occurs in shallow waters of the Pacific and Indian Oceans. Mature individuals, which can live for over a century, have been known to exceed 1.4 meters (5 feet) in length and weigh in at over 260 kilograms (570 pounds).
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Diver gives the okay sign as the last clam is situated. |
Resembling pouty lips, colourful clam mantles provide homes for symbiotic algae which provide the clams with food and give them their colour. For this reason, giant clams can only survive in shallow, well-lit areas. An assessment of Hamilo's initially-seeded clams revealed that mantle coloration has considerably improved.
Pagaduan added "When we planted the first batch last November, all clam mantles were pale ochre. Now, each clam displays electric hues of blue and violet - an indicator that the area is conducive to clam growth."
Vital part of a healthy reef
Giant clams are an integral part of the reef, serving as nurseries for a host of fish and invertebrate species -including damsels, gobies and tiny crustaceans such as shrimp. Sedentary organisms like sponges, tunicates, corals and algae find giant clam shells perfect substrates for attachment - most mature giant clams are partially encrusted by other reef organisms. Lastly, giant clams act as filter feeders - sifting planktonic debris from the water for food - thereby improving overall water quality.
Population decimated for food and pet trade
Once common throughout Philippine reefs, excessive hunting for the food, pet and curio trade has all but depleted wild populations by the mid-1980s, prompting the IUCN to classify them as vulnerable. An attempt to restore natural clam populations is now being spearheaded by Dr. Suzanne Mingoa-Licuanan of the University of the Philippines Marine Science Institute (UPMSI). To date, several species of giant clams have been reseeded in over 50 reefs nationwide.
