This research conducts a comparative assessment of three key physicochemical parameters (pH, total alkalinity, and total hardness) and the ichthyofauna of four rivers (Akor, Okuugo, Ehie, and Anya) located in Ikwuano Local Government Area, Abia State, Nigeria. The study spans four clans: Ibere, Oloko, Ariam, and Oboro. To ensure comprehensive sampling, the rivers were divided into three distinct transects (upper, middle, and lower courses) with a 100-meter interval between each. Sampling was conducted over two seasons (wet and dry) to capture seasonal variations. pH levels were measured using a Hach HQ11 pH Meter, calibrated to values of 4, 7, and 10. Total alkalinity (mg/L as CaCO₃) was determined in-situ using the Hach Alkalinity Meter AL-100, while total hardness (mg/L as CaCO₃) was measured using a Thermo Scientific Orion 9600 Hardness Meter. For ichthyofauna assessment, cast nets and seine nets were employed for fish capture, and species were identified using a freshwater fish chart. The fish species recorded include Oreochromis niloticus, Clarias gariepinus, Hepsetus odoe, and Malapterurus electricus. The study found that during the dry season, pH values ranged from 8.8 to 9.5, whereas in the wet season, they ranged from 7.5 to 8.5. Total alkalinity was highest during the dry season (100 mg/L as CaCO₃), while the wet season exhibited values between 50–100 mg/L as CaCO₃. Similarly, total hardness was significantly higher in the dry season (150–300 mg/L as CaCO₃) compared to the wet season. These physicochemical parameters were found to be within acceptable ranges for sustaining the health of the ichthyofauna. The study also revealed that seasonal rainfall during the wet season diluted the rivers’ mineral and ion content, while evaporation in the dry season concentrated these elements, leading to elevated levels of alkalinity and hardness. This study underscores the influence of seasonal changes on river water chemistry and its implications for aquatic life. It recommends further research into these parameters in other regions for a broader understanding of their impact on freshwater ecosystems.
Keywords: Physicochemical parameters, ichthyofauna, river systems, pH, total alkalinity, total hardness, seasonal variation, Nigeria