Preliminary Studies On The Limnological Stock Assessment, Productivity And Potential Fish Yield Of Ojirami Reservoir, Edo State, Nigeria

Abstract

The report documents for the first time, preliminary limnological stock assessment of the Ojirami water supply reservoir, Edo State, Nigeria, with respect to water quality, phyto- and zooplankton communities, primary productivity and potential fish yield. The physical and chemical characteristics and the plankton community of the reservoir were typical of Nigerian inland waters. Nine species of phytoplankton (Chlorophyceae 5; Bacillariophyceae 2; Cyanophyceae 2) and 33 species of zooplankton (Copepoda 5; Cladocera 10 and Rotifera 18.) were identified in the reservoir. Pelagic primary productivity (PPP) using the Light and Dark bottle technique was 0.63g02m-2d-1 (falling into the low range classification of 1-0.49gm O2m-2d-1, while Potential Fish Yield (PFY) from the Morpho-Edaphic Index (MEI) was 49.6kg ha-1. These results are discussed in relation to other water bodies in Nigeria. This report has only provided preliminary data on the reservoir but it is hoped that future studies would benefit from this initial benchmark information.

Key words: water quality, phytoplankton, primary productivity, zooplankton, potential fish yield