Effect Of Fertilizer (NPK) On The Survival Of Oreochromis Niloticus Larvae:- Bernard, Janet J

ABSTRACT r X i uBffli |lIEffect of NPK (15:15:15) fertilizer on the survival of Nile tilapia (Oreochromis niloticus) yolk sac larvae was determined in 96hours static bioassay. The fish were exposed to different NPK (15:15:15) fertilizer concentrations. The acute toxicity test ofNPK fertilizer was carried out in the laboratory to determine its toxic effect on larvae of O. niloticus. The different concentrations were obtained through exploratory test of aqueous solutions of serially-diluted toxicant. The work was done using five (5) concentrations 25mg/l, 50mg/l, 75mg/l, 100mg/l, and 125mg/l of fertilizer and a control. Test concentrations and control were, replicated lour (4) times. The 96hrs LC50 ofthe exposed fish was 50mg/l with Lower Limits of-3.679 and Upper Limits of 6.511 respectively. During the exposure period, there were loss of equilibrium, agitated swimming, air gulping and finally death. The results showed that the mortality of O. niloticus larvae exposed to NPK fertilizer in water increased with increase in concentration and time of exposure, while survival of O. niloticus yolk sac larvae decreased with increase in concentration and time of exposure. Physicochemical water parameters showed no significant difference (p>0.05) between dissolved oxygen and pH. The toxicological implications of the finding in relation to aquatic ecosystem are discussed.