Okeke J.J. , Okoye C.O. , Ayadiuno R.U. , Nwosu M.C. , Ibemenuga K.N. , Arazu V. N.
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Journal : International Journal Of Forest, Animal And Fisheries Research(IJFAF)
Fish constitute more than half of the total number of all the aquatic vertebrates in the world; thus, a study was carried out for six months from January-June, 2016 to investigate the physico-chemical parameters, composition, abundance and diversity of ichthyofauna present in some sections of Omambala, Ezu and Ahommiri Rivers in Anambra state, Nigeria. Water samples were collected for physico-chemical analysis and fish samples were also collected with the assistance of artisanal fishermen using different types of traditional fishing gears namely - gill nets, cast nets, hook and line, local traps (baited) and bag nets to evaluate fish species composition and abundance. The result of the physico-chemical analysis showed uniform values for temperature (25±0.16oC-30±0.48oC), dissolved oxygen (3.65±0.78-5.65±0.11mg/l) and biochemical oxygen demand (13±0.03-16±0.08mg/l) which favoured the distribution of fishes present in different sections of the three Rivers. A total catch of 11,031 fishes were recorded from the three Rivers which comprised 11 orders, 29 families, 43 genera and 69 species. Umuoba-Anam section had 9691 catches, Ebenebe section (702) and Awa section (638). Monthly composition showed highest in March (1,909) and June (2,294) for dry and rainy seasons respectively. Seasonal composition showed highest during the rainy season with a total number of 5922 fishes while 5109 fishes was recorded for the dry season. The diversity indices of the three Rivers indicated diverse communities with ten common species variety and Shannon Weiner (H’) diversity index of 2.755-3.682. Tilapia zilli (22.2%) was the most common and abundant species followed by Clarias anguillaris (21.4%), Malapterus electricus (18.9%), Heterobranchus bidorsalis (15.4%), Xenomystis nigri (14.6%), Heterotis niloticus (13.0%), Auchenoglanis monkei (11.0%), Tilapia dageti (10.2%), Hepsetus odoe (8.1%) and Bagrus filamentosus (7.2%). The study revealed that taxa richness and species diversity increase with increased water level and uniform physico-chemical changes. Further survey of fish species diversity and abundance should be carried out continuously for a longer period on a larger scale for a thorough assessment of the water bodies and their fishery potentials.