Diversity and relative abundance of fishes in some rivers of the Tekeze and Blue Nile (Abay) basins, Ethiopia

Diversity and relative abundance of fish species of Gendwuha, Guang, Shinfa, and Ayima Rivers from Tekeze and Blue Nile (Abay) basins were studied. One thousand sixty three (1063) fish samples were collected using gillnets of 6, 8, 10, 12 and 14 cm stretched mesh sizes, monofilaments with stretched mesh sizes of 5, 10, 15, 19, 25 35, 45 and 55 mm as well as hooks and lines. Fish sampling was also done by fyke and cast nets. The fishes were collected in dry and wet seasons in October-November 2007 and January 2008. Twenty seven species were identified that belong to 18 genera and 13 families. Cyprinidae, Alestidae, Bagridae and Mormyridae were the dominant families, with respect to numbers of species. Cyprinidae was the most dominant family in all the four rivers, and it comprised 51.5 % (Index of Relative Importance-IRI) of the catches from the four rivers. Labeobarbus and Mormyrus were the most represented genera with 4 and 3 species each, respectively. A higher number of species was recorded from Rivers Shinfa and Ayima with 20 species each, whereas 18 and 16 species were identified from Guang and Gendwuha Rivers, respectively. Fish contributes to food security of the surrounding communities and understanding the resource potential and recommending appropriate management options for sustainable utilization of this fishery need further research. Keywords/phrases: Blue Nile basin, Conservation, Fish abundance, Fish diversity, Tekeze basin Ethiop. J. Biol. Sci ., 8(2): 145-163, 2009