Species Composition, Seasonal Occurrence and Abundance of Freshwater Fishes in Ayeyarwady River Segment, Sagaing Region, Upper Myanmar

Abstract

The study was carried out to assess the fish species composition, seasonal occurrence, and abundance at Ayeyarwady River segment, Sagaing Region, upper Myanmar from July 2017 to June 2018. A total number of 52 species of 37 genera distributed among 20 families and 10 orders of freshwater fishes were recorded during the study period. The highest composition of species was observed in the order Cypriniformes and the lowest in Osteoglossiformes, Anguliformes, Beloniformes and Tetraodontiformes . The highest number of species was recorded in October (cool season) and the lowest were noted in June (dry season) during the study period. The highest numbers of individuals was recorded in order Clupeiformes. According to relative abundance value, the four species were noted as very common (Vc), eight species were common (C), and the remaining 39 species were categorized as uncommon species (Uc). Out of the 51 species recorded, 25 species were encountered at every month and the total of five endemic species and one introduced species was observed during the study period.