Effect Of Riparian Land-Use Practices On Water Quality And Fish Composition Of Oyan Dam

Samuel Ajibola Olowe
Aquaculture and Fisheries Management, Federal University of Agriculture Abeokuta, Ogun State
October, 2014
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This study investigated the effect of riparian land-use practices on water quality and fish composition of Oyan Lake and how sensitive the fishes are to various changes in water parameter and riparian land use. Water sample were collected from all Landing-site of Oyan-Lake, questionnaire were distributed and catches were weighted and identified in collecting relevant information. The following parameters were tested for: Temperature, Hydrogen ion Concentration, dissolved Oxygen, Total Dissolve Solids, Nitrate and Phosphate level, Cadmium and Lead level. The mean concentrations of the other parameters are: Temperature: 27.52oC, pH 6.86, Conductivity: 80, Dissolved Oxygen 6.76mg/l, TDS 0.042, Nitrate 36.58, and Phosphate 0.625. The highest numbers of people living around the water body were found practicing both farming and fishing using pesticide, herbicide and fertilizer which have influence on water body and in fishing using both active and passive gear. Larger percentages are married with minimum of primary school certificate. Villagers were found washing of cloth detergent beside the river banks.
Eight (8) families of different fish species are found with the following in abundant: MORMYRIDAE (Hyperopisus bebe) BAGRIDAE (Chrysichthys nigrodigitatus) SCHILBEIDAE (Schilbe mystus) CENTROPO MIDAE (Lates Niloticus). The families of CICHLIDAE (Sarotherodon galilaues, Tilapia Zillii) are found to be both in abundant and very common. The various activities around the lake such as (a) use of herbicides, pesticides and inorganic fertilizers has some effect on the soil which are later flushed in to the lake. This might have effect on the water parameter which might have lead to extinction of various species previously report by past researchers in same lake. It was therefore recommended that the orientation/advice on land management practices should be given to the farmer and Close area / season should be adopted.