Sublethal effects of ammoniacal fertilizer effluents on three commercial fish species from Niger Delta area, Nigeria
Ekweozor, I.K.E.; Bobmanuel, N.O.K.; Gabriel, U.U.
Journal of Applied Science and Environmental Management 5(1): 63-68
2001
Document Number: 259952
Sublethal effects of various concentrations of fertilizer effluents on the tail beat frequency per minute (TBF minute-1) and opercular beat frequency per minute (OBF minute-1) of Oreochromis niloticus, Clarias gariepinus and hybrid (Heterobranchus bidorsalis (female) x C. gariepinus (male)) were examined in a static 96-hour bioassay under laboratory conditions. Effluent concentration, ammonia (ionized and un-ionized), urea and pH significantly affected TBF and OBF of the three species. Ammonia particularly, the un-ionized form exacted the most significant effect on TBF and OBF. OBF appears be a more sensitive indicator of stress than TBF and may therefore be more suitable for detecting sublethal physiological effects of pollutants. This study further revealed that the fertilizer effluents have variable compositions whose values may far exceed the allowable limits and hence may pose great danger to the aquatic environment.