Modelling catch per unit effort of the Black Volta near the Bui dam in Ghana

Abstract The chlorophyll a concentration and water level of the Black Volta near the Bui dam were studied in relation to fish production as measured by catch per unit effort ( CPUE ) between February 2011 and December 2012. The primary objective was to develop a simple linear regression model for predicting CPUE levels. The mean estimated CPUE for 2011 and 2012 was lower (6.23 kg canoe −1  day −1 ) in the postwet season than in the dry season (10.86 kg canoe −1  day −1 ) with a mean of 7.95 kg canoe −1  day −1 . Hence, the dry season was the most important season for fish catches in the study area. Predictor variables that significantly explained CPUE levels were chlorophyll a (positive correlation) and water level (negative correlation) ( P  =   0.0002). The model was validated with independent data from the same Black Volta in 2011 and 2012. This model, CPUE = (0.062 × chlorophyll a ) − (0.456 × water level) + 3.363, explained 91% CPUE variability. Independent validation indicated that the model had the potential to predict CPUE (as a measure of fish production) in the Black Volta near the Bui dam. Hence, the model is also a valuable tool to predict future trends in the CPUE levels of the Black Volta.