Fish Assemblage Patterns in Littoral Zone of Nam Oun Reservoir, Sakon Nakhon Province, Thailand

Abstract

Spatio-temporal variations in fish assemblages in the littoral zone of Nam Oun reservoir, Sakon Nakhon Province, Northeast Thailand were investigated during May 2008 - April 2009 using gillnets with mesh sizes of 20-80 mm. There were six sampling stations around the reservoir. Fish sampling resulted in the collection of 29, 151 individuals, comprising of 44 species from 18 families. Twenty-three species were found in all sites with Puntius brevis as the most abundant species. The most abundant numerically was obtained at S6-site (Ban Kok Sung). Species richness, diversity index and relative evenness index were statistically different among sampling sites but not at different months. S4-site (Ban Kudtakab) showed the highest values for species richness and species diversity index. Meanwhile, S1-site (Ban Kok Sa-ad) showed the highest relative evenness index. Cluster analysis and multidimensional scaling (MDS) revealed there are four groups in terms of sampling-sites (25% of similarity level) and three major groups in terms of months of sampling (33% of similarity level).