THE STATUS OF MOLLUSK DIVERSITY AND PHYSICAL SETTING OF THE MANGROVE ZONES IN CATANDUANES ISLAND, LUZON, PHILIPPINES

The status of mollusk diversity and physical setting of mangrove areas in Catanduanes island, Luzon (Philippines) are described. A total of 57 species of mollusks, consisting of 27 gastropods and 30 bivalves were recorded in the island. Registering higher values of species diversity indices (Margalef) and species richness (Menhinick) are the prosobranch, Terebralia sulcata; corbiculid bivalve, Geloina coaxans; potamidiids, Cerithidea cingulata and Cerithidea rhizophorarum; and two other species of the genus Littorina (Littorinopsis). Using the physiographic model, majority of the mangrove areas under study follow the composite river and wave-dominated setting with some few areas having the wave-dominated, tide-dominated allochthonous setting.