Victoria O. AYUBA, Victor T. OKOMODA, Samuel I.O. OGAH (NIGERIA)
Abstract. Fertilizers application might positively or negatively affect the aquatic environment to the benefit or detriment of aquatic organisms including fish. Inorganic fertilizer are used in pond for fertilization purposes, however, beyond a tolerance limit it could be potentially dangerous to fish causing stress as well as death, this study therefore seek to determine acute toxicity of NPK 20:10:10 fertilizer to Fingerlings of African catfish Clarias gariepinus using a static bioassay test. African catfish were obtained from a homogeneous source and acclimatized for two weeks. The 96 hour LC50 of NPK 20:10:10 to Clarias gariepinus was observed to be 3.299 g/L with lower and upper limits of 3.232 g/L and 3.337 g/L respectively, toxicity of Nitrogen in NPK 20:10:10 was estimated to be 0.659 with lower limits of 0.6463 and upper limits of 0.675 while toxicity of potassium/phosphate in NPK 20:10:10 were obtained to be 0.329 with lower and upper limits of 0.3232 and 0.3378 respectively. Toxicosis symptoms observed includes loss of balance, respiratory distress, vertical and erratic movement and death. Observation of toxicosis symptoms in experimental fish began on second day of study with it peak at about the 62nd hour. Precautious use of NPK in pond fertilization is advised.
Keywords: African Catfish, fertilizer toxicity, stress pattern, agricultural fertilize