Water quality parameters and fisheries in central river region of the Gambia: Differences between wet and dry seasons

This research was aimed at studying the two seasonal changes in water quality of Central River Region (CRR) of The Gambia to influence fish assemblage. Physicochemical properties were measured in-situ with a portable YSI multiprobe water meter and fish sampling was done using a fishing net of 100 × 4 m. A total of 2,039 fishes, represented by sixteen species totaling to a biomass of 49, 236.3g were caught by seine netting. Laboratory analysis were also done for nitrite, nitrate, ammonia and phosphate in CRR using a spectrophotometer. The water variables were subjected to Principal Component Analysis (PCA) which showed a strong positive correlation between oxygen and pH, conductivity and TDS and negative correlation between oxygen and ammonia and nitrate (p ≤ 0.05). The research further showed that seasonal variation in environmental conditions have increased and are negatively influencing fish assemblage in CRR, determined from a three-decade time series of rainfall and atmospheric temperatures.