The Effects of Flood Pulse on the Spatial and Temporal Dynamics of Fish Diversity in the Raphiphat Canal, Thailand

Abstract

This paper analyzes the effects of flood pulse on the spatial and temporal dynamics of fish diversity in the Raphiphat canal, Thailand, resulting from a study carried out in the period from May to December 2021. The fish samples were collected every month, covering the pre-flooded season (May to August) and the flooded season (September to December) on the rainy seasons at eight sampling stations. Fish were caught using cast nets with a mesh size of 1.5 cm and 2.5 cm, and gill nets with a mesh size of ¾ inch, 1.5 inches, and 2 inches. All data were analyzed to find out the fish diversity indices. A multivariate method of cluster analysis was used for data analysis. The result indicated that there was a total of 4,998 individual fish representing 33 species belonging to 25 genera and 14 families. The four most dominant fish varieties in the Raphiphat canal in terms of amount were Puntioplites proctozystron, Barbonymus gonionotus, Cyclocheilichthys enoplos, and Oreochromis niloticus which were distributed at all research stations. For temporal dynamics of fish diversity, the average species richness was 15.74±7.18. The highest species richness was found in August, and the lowest species richness was found in June. The H´ index 2.46±0.47 was found in December to May. The relative evenness index (J´) was 0.91±0.03 and varied between December and May. The cluster analysis each month in the Raphiphat canal can divide the fish community into 5 clusters.