Hydrogen ion (Ph), ammonia, dissolved oxygen and nitrite concentrations in catfish water re-circulatory and semi-intensive static-water systems
Hydrogen ion (pH), dissolved oxygen, ammonia and nitrite concentrations were studied monthly in two systems (re-circulatory and semi-intensive of 3 m2 sizes) each for six months. The systems were each stocked with 200 g of Clarias gariepinus fingerlings. Results showed that all parameters were within acceptable limits in each system and varied significantly (P<0.05) except total ammonia concentration in the outdoor tank (P=0.0769). Comparatively, total ammonia (P = 0.0016) and nitrite (P=0.0000) variations in the two systems were highly significantly different (P <0.05). Positive significant correlation was established between total ammonia and nitrite only in the concrete tank (r = 0.9367; P = 0.0059) only. The relatively high dissolved oxygen values in the systems must be maintained to help eliminate nitrogenous wastes. The water quality results from both systems indicated that the water quality in the concrete tank is of a higher and better quality than in the re-circulatory open system.
Key Words: Water re-circulatory and semi-intensive static-water systems, water quality parameters