Aishat Abisola YUSUFF

Zooplankton and macrobenthic invertebrate fauna are good indicators of the overall water quality of rivers, as changes in water quality affect their general distribution and abundance. This study investigates the community structure of zooplankton and macrobenthic invertebrate fauna of Siluko River, Edo State, Nigeria. Zooplankton and macrobenthic invertebrate samples were collected monthly from July 2016 to March 2017 at four designated stations between 09:00 hours and 12:00 hours using plankton net and filtering 100litres of water respectively and thereafter analyzed in the laboratory using standard methods. A total of 20 zooplankton taxa comprising 386 individuals belonging to the groupCladocera, Cyclopoida, ploimida and flosculariaceae were encountered. Tropocyclops prasinus had the highest number of abundance. Cladocera accounted for 31.00% while Cyclopoida, Ploimida and flosculariaceae accounted for 62.00%, 6.00% and 1% respectively. Shannon-Weiner’s diversity indices showed that highest value of 3.583 was obtained in station 4 and lowest value of 2.731 was obtained in station 2 for the zooplankton. There were no observed seasonal variation in Cladocera and Copepods composition and abundance except for Rotifers which were more abundant in dry season. A total of 52 macrobenthic invertebrates taxa comprising of 2163 individuals, three phyla; Annelida, Arthropoda and Mollusca were encountered in this study. Centroptilum sp. had the highest abundance. Diversity and evenness indices showed that there was no significant difference (p>0.05) in species composition across the study stations. Using the Shannon-Weiner’s diversity index, highest value was obtained in station 1 and lowest was obtained in station 3. Ephemeroptera, Plecoptera, Trichoptera (EPT) index revealed that the water quality at stations 1, 3 and 4 were acceptable while that of station 2 was categorized as good. The zooplankton and macrobenthic invertebrate communities in Siluko River were characterized by species which indicated good water quality. However further studies are recommended to monitor the changes to this water body and their probable health effects as anthropogenic activities such as farming and housing development are on the increase around this stretch of the River.

Zooplankton and macrobenthic invertebrate fauna are good indicators of the overall water quality of rivers, as changes in water quality affect their general distribution and abundance. This study investigates the community structure of zooplankton and macrobenthic invertebrate fauna of Siluko River, Edo State, Nigeria. Zooplankton and macrobenthic invertebrate samples were collected monthly fromJuly2016toMarch 2017 at four designated stations between 09:00 hours and 12:00 hours using plankton net and filtering 100litres of water, respectively and thereafter analyzed in the laboratory using standard methods. A total of 20 zooplankton taxa comprising 386 individuals belonging to the group Cladocera, Cyclopoida, ploimida and Flosculariaceae were encountered. Tropocyclops prasinus had the highest number of abundance. Cladocera accounted for 31.00% while Cyclopoida, Ploimidaandflosculariaceae accounted for 62.00%, 6.00% and 1% respectively. Shannon-Weiner’s diversityindices showed that highest value of 3.583 was obtained in station 4 and lowest value of 2.731was obtained in station 2 for the zooplankton. There were no observed seasonal variation in Cladocera and Copepods composition and abundance except for Rotifers, which were moreabundant in dry season. A total of 52 macrobenthic invertebrate taxa comprising of 2163individuals, three phyla; Annelida, Arthropoda and Mollusca were encountered in this study. Centroptilum sp. had the highest abundance. Diversity and evenness indices showed that therewas no significant difference (p>0.05) in species composition across the study stations. Using Shannon-Weiner’s diversity index, highest value was obtained in station 1 and the lowest was obtained in station 3. Ephemeroptera, Plecoptera, Trichoptera (EPT) index revealed that the water quality at stations 1, 3 and 4 were acceptable, while that of station 2 was categorized as