VARIATION OF WATER QUALITY PARAMETERS AND CORRELATION AMONG THEM AND FISH CATCH PER UNIT EFFORT OF THE TONO RESERVOIR IN NORTHERN GHANA

Abstract

Water quality is essential for fish survival and growth in reservoirs. However, little information is known about the water quality status and its relation with fish production in the Tono Reservoir. This study sought to assess water quality parameters and examine association among them as well as determine the correlation between the water quality parameters and fish catch per unit effort of the Tono Reservoir. A three-level stratified sampling was adopted and samples were collected on a monthly basis. Water quality parameters such as water level, temperature, pH, electrical conductivity, transparency, turbidity, dissolved oxygen, chloride, sulphate, phosphate-phosphorus, silica, nitrate-nitrogen, nitrite-nitrogen, chlorophyll-a, and fish catches were measured simultaneously from each of the three strata of the reservoir. The water quality parameters of the reservoir fell within the recommended range for fish production. Concentrations of water quality parameters for the riverine, transitional and lacustrine zones showed no significant difference (p > 0.05). Catch per unit effort correlated significantly positive with only chloride (r = 0.61, p < 0.05) attributable to fertilisers used on surrounding farm lands and carried by runoff or floods to the reservoir. The reservoir could be classified as mesotrophic based on chlorophyll-a concentration. It was recommended that the reservoir water quality should be monitored quarterly by the Ministry of Fisheries and Aquaculture Development to ensure safe fish production.