Authors: Omoniyi I. T. Oyekanmi F. B. Akegbejo-Samsons Y.
OIDA International Journal of Sustainable Development, Vol. 04, No. 06, pp. 31-38, 2012
Abstract
Limnological features in relation to prawn catch at Asejire Lake and Erin-Ijesa waterfalls were studied from 2007 to 2009. The preponderance of M.vollenhovenii and C. africana in their natural habitats with intent towards acculturation was investigated. Sampling of each site for prawn abundance was bi- weekly. Prawns were collected with properly baited traps and scoop nets. Catches obtained from the two sites were isolated and conveyed in ice chest boxes to the laboratory for examination. Water samples were collected for physical and chemical water quality parameters assessment. Data collected were subjected to one way analysis of variance (ANOVA) and where differences in mean existed Duncan Multiple Range
test was carried out using Statistical Package for Social Science (SPSS). Abundance in terms of number, sex and age were more during the wet season with a peak in August. Both adults and juveniles showed a progressive increase from late dry season to mid-rainy season (August). The results of physical and chemical parameters revealed that the mean water Temperature, Transparency, Depth, Dissolved Oxygen, pH, Alkalinity, Total Dissolved Solid, Conductivity, Nitrate and phosphate were 27.52±2.050C, 1.5 ± 0.44m, 3.16±1.3m, 6.70±0.82mg/l, 7.28 ± 0.55, 144.17 ± 30.05mg/l, 388.46± 211.48mg/l, 82.90±1.60µohms/cm, 4.62±0.79mg/l and 0.27± 0.04mg/l respectively at Asejire lake which were not significantly different (P<0.05) from the values of Erin-Ijesa waterfalls which were 27.77 ± 2.270C, 1.71 ± 0.39m, 1.43±0.22m,6.21±0.77mg/l,7.25±0.68, 136.62±41.6mg/l,402.13±253.25mg/l,83.40±1.86µohms/cm,4.76±0.76mg/land0.2 ±0.05mg/ respectively. Both water bodies exhibited features that are typical of tropical environment, as almost similar limnological factors were recorded which fell within the range that can support aquatic life. High value in Condition factor for both species under investigation shows the total well being of the prawns and suitability of their environment for sustainability.