Preliminary study on diversity of intertidal gastropods in Barangay Day-asan, Surigao City, Philippines

Unregulated harvesting and habitat degradation of marine gastropods are major anthropogenic activities done by the local people in Barangay Day-asan, Surigao City, Philippines. This study was undertaken to determine the diversity of marine gastropods found in the intertidal of Dapya Island. Collection of specimens was done through hand picking and beachcombing methods in the three established study stations. Data revealed a total of 184 individuals belonging to 37 species in 5 orders, 15 families and 25 genera. The order Neogastropoda obtained the highest number of species with 15 species, followed by order Mesogastropoda with 10 species, order Archaeogastropoda with 7 species, order Neritopsina with 4 species and order Caenogastropoda. Among the 37 species, Nerita undata was the most abundant. Shannon-Weiner diversity index revealed that station 2 (H=1.193) obtained the highest species diversity, followed by station 3 (H= 1.103) and station 1 (H=1.063). The Bray-Curtis analysis of species composition showed two different clusters of habitat. Cluster 1 is composed of two related habitats joined by Stations 1 and 2 with Si= 54.26% and cluster 2 composed of Stations 3 and 1 with Si= 40.65%. Furthermore, among the 37 species, six of which were concordant in all study stations viz., Angaria delphinus, Astralium calcar, Conus miles, Lambis lambis, Euprotomus bulla and Canarium labiatum. The results of the study showed a low diversity of intertidal gastropods in Barangay Day-asan. The area is known to be the most gleaned by locals and it is been already disturbed due to overharvesting of gastropod species.