Diversity and relative abundance of fishes in some temporary and perennial water bodies of the Baro basin, Gambella, Ethiopia

Abstract

The diversity and relative abundance of fish species of the Baro basin were studied using samples taken from seven sites. Fishes were sampled using seines, dip nets (mesh sizes 0.5 cm and 1 mm), hook and line, fish traps, cast net (local fishermen) and electro-fishing. Specimens were identified to species level using taxonomic keys found in the literature. Shannon diversity index (H’) and Index of Relative Importance (IRI) were computed to evaluate diversity and relative abundance of fish species, respectively. A total of 51 species belonging to 38 genera, 20 families and 11 orders were identified. The number of species varied among sampling sites. Thus, the highest number of species was recorded from Alwero (H’=2.56) followed by Obela, Baro at Gambella and Gilo (H’=2.03 each), Itang (H’=1.91) and Tdha (H’=0.35). Mormyridae, which comprised 8 species, was the most dominant family in number of species followed by Mochokidae (7 species) and Cyprinidae (6 species). Barbus prince was found in six of the studied sites whereas Oreochromis niloticus was found in five sites, Brycinus macrolepidotus, Siluradon auritus, Clarias gariepinus, Barbus stigmatopygus and Polypterus senegalus were each found in four sites, and thus, were considered the most dominant. IRI showed that O. niloticus (IRI=37.2%) was the most abundant species followed by S. auritus (IRI=14.6%), B. macrolepidotus (IRI=13.1%), B. stigmatopygus (IRI=10.0%), B. prince (IRI=9.8%), and P. senegalus (IRI=7.4%). Further comprehensive assessment of the fish diversity of the basin and socio-economic aspects for sustainable fish resource utilization is recommended.

Key words/phrases: Baro basin, Ethiopia, Fish diversity, Relative abundance.