The interactive effects of rainfall, temperature and water level on fish yield in Lake Bangweulu fishery, Zambia.

Abstract

Climate variability and climate change have negative impacts on fisheries ecosystems and people who derive livelihoods from them. Zambian climate is projected to increase 2 °C in mean temperature by 2070, and further reports suggest that rainfall will drop by 8-30% of the normal average. This study was undertaken to determine the effects of rainfall, temperature and water level on fish yield. The study used both primary and secondary data sources. The major statistical techniques employed in this research include estimation of mean frequencies and correlation coefficients, as well as multivariate regression analyses, to determine the relationships among climate (temperature, rainfall), water level, and fish yield, using the Statistical Package for Social Sciences. The results showed an increase in temperature of 0.3 °C, a decrease in rainfall of 3% and a water-level loss of 1.7 m since 1974. During the same period, fish yield increased by 53%, compared to increases in fishers and boats of 57% and 55%, respectively. The resultant Catch per Unit of Effort (CpUE) decreased from 12 kg/net/night to 1.5 kg/net/night. Findings indicate that there are significant correlations between temperature, rainfall (one-year lag), water level and fish yield. Based on the results, there is strong recommendation to incorporate climate variability and change in the modelling of fisheries management to reduce the impacts of climate variability and change on fisheries-based livelihoods.