COPEPOD COMMUNITY OF OGBA RIVER

ABSTRACT

Increased anthropogenic disturbance has influenced freshwater ecosystems globally by causing
habitat degradation and biodiversity loss. In the present study, copepods community structure of the Ogba River, an urban river in Edo State, Nigeria was investigated seasonally in August and September 2021 (wet season) and January 2022 (dry season). Zooplankton and water samples both were collected using standard method and analyzed. A total of 80 individuals comprising 6 species and 1 family were identified and recorded during the study period. The dominant species of Copepod were Mesocyclops aspericornis (38%), followed by Thermocyclops decipiens and Thermocyclops neglectus (19% each), the least species were Mesocyclops rarus (6%). The calculated diversity indices indicated that station 1 was more diverse followed by station 2 and 4, while copepod species in station 3 were least diverse. Community composition was similar at both stations 2 and 4, but varies seasonally across the four stations. Higher species number and density was found during the wet season with a trend of declining proportion towards the dry seasons. The abundance of copepod species is positively correlated with water physico-chemical parameters namely, water temperature, water level, water velocity, pH, transparency, total dissolved solids, turbidity electrical conductivity, ammonium, phosphate, sulphate, chromium, iron and copper. Results from this study provide an update of copepod community structure in Ogba River.