HomeThe Palawan Scientistvol. 12 no. 1 (2020)

High density of Tridacna crocea in Rita Island, Puerto Princesa City, Palawan, Philippines

Jemima C. Daño | Elmer G. Villanueva | Roger G. Dolorosa



In spite of being a protected species in the Philippines, the Tridacna crocea or crocus clam, the smallest among eight known giant clam species in the country, is getting rare in most reef areas of Palawan. However, a high density of this species has recently been noted in Rita Island, Ulugan Bay. A total of 44 photos with known dimensions having a total area of 13.26 m2 suitable habitats with clams were analyzed for size structure and density of T. crocea. In total, 215 T. crocea were noted with 84.91 (±25.6) mm average shell length (±sd). The average density (±sd) was 16.22 (±15.75) individual (ind)∙m-2 but the clams had occurred up to 17 individuals in 0.28 m2 or 59.91 ind∙m-2. This high density of T. crocea could be due to suitable environment and the absence of exploitation within the vicinity of the island resort. The importance of other resorts in biodiversity conservation may be investigated.