Impact of Irrigational Runoff on Fish Biodiversity in River Ngadda, Maiduguri – Borno State

Irrigation is a dry season agricultural activity that was known to man for centuries. Agricultural runoff has been identified as the major nonpoint sources of pollution into surface waterbodies which changes physico – chemical parameters thereby impacting on biodiversity such ecosystem. River Ngadda receives pollutants from irrigational sites along river bank. The study aimed at assessing impact irrigation fish in Ngadda, Maiduguri, Borno State, Nigeria. objectives were determine and examine river. divided 4 sampling Stations. Water samples collected biweekly period 6 months stations. qualities (total nitrogen (TN), ammonium (NH4+), total phosphorus (TP), organic carbon (TOC), dissolved solids (TDS), turbidity (Tur) suspended (TSS) determined using standard methods. Capture recapture method employed relative abundance species Lincoln index. mean Total Nitrogen (TN) ranges 5.02 mg/L 8.31mg/L, (NH4+) 0.93mg/L 2.01, phosphorous (TP) 0.07mg/L 1.81mg/L. Organic Carbon (TOC) 5.87mg/L 7.45mg/L, Turbidity 27mg/L 31mg/L, Dissolved Solids (TDS) 198NTU 298NTU, Suspended 34mg/L 47mg/L water Temperature 26°C 28°C. A families 10 fishes