Diversity, Abundance, and Local Use of Fishes in Lake Danao, Ormoc City, Philippines

Abstract

Lake Danao lies within the Lake Danao Natural Park in Ormoc City, Leyte, Philippines. The lake provides a habitat for various aquatic flora and faunal species. However, existing data on fish assemblage in Lake Danao is scarce and outdated. This study determined Lake Danao’s diversity, abundance, and local use of fish. With the help of local fishers, fish samples were collected from different parts of the lake twice a month for 14 months (March 2021 to June 2022). In addition, an ethnoicthyological survey was conducted to supplement the information on the provenance, endemism, and local use of the fish species in Lake Danao. This study recorded eight species of fish in Lake Danao, and only two are considered native (Anguilla marmorata and Clarias batrachus). Only five species were obtained from the fishers throughout the entire sampling period. On average, Glossogobius giuris was the most abundant species (95.96%), while Channa striata was the least (0.07%). The low Shannon-Weiner diversity index (mean = 0.19) and high Simpson’s dominance index (mean = 0.92) indicate low diversity and dominance of other species (e.g. G. giuris). No significant difference was observed in the diversity, dominance, and evenness of fishes between the sampling months. All of the fish species were used as alternative food sources. With the dominance of introduced species, local authorities are strongly encouraged to strictly regulate the entry, possession, and cultivation of exotic fish in Lake Danao and to continue the aquatic biodiversity assessment and monitoring in the area.