Short CommunicationDiversity and relative abundance of fishes in the head of Blue Nile River, Ethiopia

Abstract

Diversity and relative abundance of fishes in the head of the Blue Nile River (from the outlet of Blue Nile River in Lake Tana to Tisisat Fall) were studied from fish samples collected in wet (October 2009) and dry (March 2010) seasons. Fish sampling was done using multifilament gillnets (6, 8, 10, 12 and 14 cm stretched mesh) and monofilament gillnets (5-55 mm stretched mesh), and hook and lines. A total of 929 fish specimens, belonging to three families and seventeen species, were identified from the river. From Index of Relative Importance (IRI) analysis, the four most dominant fish species in the river were Labeobarbus intermedius (62.4%), L. crassibarbis (11.8%), Clarias gariepinus (10.1%) and Varicorhinus beso (4.04%). The cyprinid fish, L. intermedius, was the most dominant fish during the two sampling seasons. Length-weight relationships for the dominant species were found to be curvilinear. Generally, there was no species composition difference between Lake Tana and the head of Blue Nile River.

Keywords/phrases: Abundance, Conservation, Diversity, Labeobarbus, Species composition

Ethiop. J. Biol. Sci., 10(2): 207-212, 2011