Ichthyofaunal Survey in Selected Freshwater Habitats in Camarines Sur, Philippines

Abstract

Ichthyofaunal surveys were conducted in five aquatic habitats (Lake Bato, Agos River, Bagacay Falls, Lake Baao-Bula, and Pawili River) in Camarines Sur, Philippines to evaluate the diversity and distribution of freshwater fish assemblages. The study collected a total of 8,184 individuals comprising 29 species, 22 genera, and belonging to 14 families. The three most abundant groups, in order of importance were cichlids, cyprinids, and poeciliids. Overall, four fish species comprised 52% of the total abundance. These were Oreochromis niloticus (Cichlidae), Glossogobius giuris (Gobiidae), Poecilia sphenops (Poeciliidae), and P. reticulata (Poeciliidae). In terms of richness, Gobiidae are the most dominant fish group (8 species). Except in Bagacay, Shannon-Weiner diversity indices ranged from 2.04 to 2.07. Relatively high evenness indices and low dominance values were computed in the four sites. Fish densities were significantly different among the five studied areas (Friedman test: χ 2 = 43.06, P< 0.01). Bray-Curtis similarity analysis on abundance data clearly showed two clusters. Fairly high levels of similarity (49.61%— 62.81%) were observed in Baao, Bato, Pawili, and Agos, whereas Bagacay was apparently deviated from the rest. Environmental variables are fluctuating but still within the tolerable level. The survey revealed the established feral populations of introduced fish species in the four representative sites. Aquaculture operations and domestic effluents were observed to be the main key drivers of fish faunal change in the lake and stream habitats. Keywords: Bato, Camarines Sur, diversity, fish survey, Gobiidae, native species