Mollusks in the Mangrove Rehabilitation Areas in Western Pangasinan, Philippines

Mollusks are predominantly found in mangrove ecosystems. Nowadays, these are declining due to habitat disturbances. This study was conducted in Western, Pangasinan, with mangrove rehabilitation projects under Community Based Forest Management Agreement. Four mangrove rehabilitation areas were looked into: Pilar and Victory, Bolinao; and Awile and Tori-tori, Anda, Pangasinan. Purposive sampling was done in selecting the mangrove rehabilitation areas. Ten percent sampling of the areas using the belt transect quadrat method was employed. Diversity, dominance , richness and evenness indices for mollusks were determined. Mann Whitney test, Student’s t-test and Kruskal Wallis test were used. A total of fourteen kinds of mollusks species were identified. The species were Tectusfenestratus (fenestrate top), Terebraliasulcata (Sulcate swamp perith), Haliotisovinagemelin (oval abalone), Neritaplanospiraanton (flat spired nerite), Clithionoualensis(dubious nerite), Fasciolaria trapezium (trapezium horse conch), Nasarriuspullus (ribbed dog whelk), Trochusmaculatus (maculated top), Rhinoclavisvertagus (Common vertagus ), Telescopium telescopium (Telescope Snail), Isognomonephippium (saddle tree oyster) Crassostriairedali (slipper oyster), Strombuslabiatus (Plicate conch) and Polymesodaexpansa (Yellowish mangrove clam). The highest mollusks species diversity and richness indeces were observed in Victory, Bolinao. Mollusks species dominance and evenness indeces were highest in Pilar, Bolinao and Tori-tori, Anda, respectively. The study revealed a significant difference in the probability of gathering mollusks species in the four mangrove rehabilitation areas. It is recommended that fisherfolkand coastal communities be educated about the need for mollusks conservation and habitat protection. It is expected that this study may provide light to future research on mangrove fauna particularly mollusks in Pangasinan.

Keywords- species diversity, dominance, evenness and richness