Studies on Water- Media Characteristics and Bacterial Population Associated with Laboratory –reared Clarias gariepinus Fingerlings.

Abstract

This study was aimed at elucidating prevailing physic-chemical properties of culture media of the fish species, Heteroclarias, as well as the associated-bacterial population under Laboratory conditions. Adequately replicated fingerling specimens of the species were raised under artificial conditions in the Laboratory, following recommended procedures for fish culture. Physico-chemical analysis of the culture media, as well as, bacteriological studies of swab samples from external surfaces of the skin, fins and gills of the fishes, were carried out following standard protocols. The results showed that with the exception of Ammonia (range = 0.05±0.01 to 0.54±0.01mg/l), the physic-chemical properties investigated namely, pH (mean = 8.58±0.01), temperature (26.50±0.50oC), Dissolved Oxygen (6.29±0.10mg/l) and Biochemical Oxygen Demand (0.21±0.03mg/l), did not differ significantly (P>0.05); even with increasing age and/or size of the fingerlings. Six bacterial species: S. faecalis, K. pneumonea, P. aeruginosa, E. coli, B. subtilis and S. mutans, were encountered on the external parts of the fishes. However, while three of the species namely, S. faecalis, K. pneumonea and E. coli, were recovered from all three body parts of the fishes, the remaining three species were less distributed. The number of associated-bacterial species was similar for the fin and gills, and was higher than that of the skin. The bacterial load was significantly highest on the fins (mean = 12.24±2.21cfu/g), followed by the gills (9.31±2.45cfu/g) and least on the skin (6.04±1.49cfu/g).