project news

Clam Session

News item submitted by Jyot Jabbal
News item dated 4 Nov 2010


Numbers of Giant Clam (Tridacna) have been on the rise in the Bay of Antsiranana! Recent surveys conducted by our Frontier Marine Team in Madagascar have recorded an increasing abundance of the corrugated creature as they progressed away from the mouth of the bay. It is thought that inland water currents have contributed greatly to the dispersal of Tridacna in the bay area, and their presence in the coral reef environment is viewed as a positive indicator of reef health.

Some species of giant clam have been listed by IUCN as Vulnerable, and are often exploited through harvesting as curios and as a source of food. Fortunately, this does not appear to be an issue in the Bay of Antsiranana at present, and local attitudes have been encouraging enough to allow the populations to flourish.

These heavy-shelled bivalves are distributed throughout the Indo-Pacific seas, where they play symbiotic host to tiny photosynthetic microalgae known as Zooxanthellae. As a result, they are highly susceptible to water quality, temperature and sedimentation. The various species exhibit distinctive colouring and have been known to weigh up to 200kg. Given the levels of biodiversity present in Madagascar, and that several areas of the bay have not yet been explored, Frontier aims to intensify its research into the distribution and abundance of marine invertebrates such as the giant clam.

A giant clam.


Read more about the Frontier Madagascar Marine Project.