Zooplankton Community Response To Deteriorating Water Quality In Tungan Kawo (Wushishi Dam), North Central, Nigeria.

Abstract

Physicochemical variables and zooplankton were collected monthly for five months in three sites in Wushishi Dam, Niger State. The study was undertaken to look at the community response of zooplankton to some water quality variables. Dissolved oxygen (DO) showed a range of 1.9-3.0 mg/l while BOD was in the range of 1.0 – 6.0mg/l. There was significant difference (p<0.05) in DO, BOD and pH recorded among the months and sites. Temperature and transparency showed no significant difference (p>0.05). Four zooplankton orders were recorded namely; Cladocera, Copepoda, Calanoida and Rotifera, consisting of 2471 number of species. The Canonical correspondence analysis revealed a fairly strong connection between some zooplankton species distribution/abundance and some measured water quality parameters (BOD5, Transparency, Turbidity and pH). Some of the zooplankton like Megacyclops viridis, Leptodiaptomus minutus, Leptodiaptomus ashlandi, Harpacticoida sp. in February, March and June (sites 2 and 3) were strongly associated with BOD5 and Turbidity. Ceriodaphnia cornuta site 3 (February, March, April and June) is a lover of pH while Cyclops scutifer is weakly associated with conductivity. From the environmental variables data, it shows that the water body is gradually deteriorating which may be occasioned by high degree of human influences. The zooplankton abundance and composition showed a sparse distribution, which called for urgent measures to curb the menace posed by these pollutional processes going on in the dam.