Recent record of True Giant Clam Tridacna gigas from the Sulu Archipelago and insight into the giant clam fisheries and conservation in the southernmost islands of the Philippines

Abstract

The Philippines is a hotspot for marine biodiversity, particularly for giant clams like Tridacna gigas. Despite protective measures, giant clams are threatened with extinction due to overharvesting and habitat loss. We conducted a rapid documentation of a rampant giant clam fishery and trade we discovered in Panggungan Island in Sitangkai, Tawi-Tawi during our assessment, following a ship grounding incident in the area. We observed numerous empty shells of various giant clam species scattered across the area, indicating active harvesting by the community. The locals sell the meat, either fresh or dried and pearls collected from giant clams. The local community culture live with giant clams, including the true giant clam species, Tridacna gigas, along the shorelines. The largest live T. gigas individual we documented had a shell length of about 60 cm. Our study provides the first documentation of wild adult T. gigas in the Sulu Archipelago. It is also the only report of sighting of wild adult T. gigas aside from Palawan. Furthermore, our study marks the first account of giant clam trade within the Philippines since the early 1980s when the government issued a total ban on catching and selling of all species giant clams. Our findings highlight the critical need for a thorough assessment of T. gigas and other giant clam species in the biodiversity-rich Sulu Archipelago. Effective conservation of giant clams and the surrounding reefs will ensure the future of our marine ecosystems and the communities that rely on them.