Forecasting the commercial Chisawasawa (Lethrinopsspp.) fishery in Lake Malaŵi

We developed a time series modelto forecast Lethrinopsspp(locally known as Chisawasawa) for the commercial fishery based on data on Lake Malaŵi fish catch during years from 1976 to 2010. Weconsidered Autoregressive (AR), Moving Average (MA) and Autoregressive Integrated Moving Average (ARIMA) processes to select the appropriate stochastic models for forecasting annual commercial Chisawasawa catch from Lake Malaŵi. Based on ARIMA (p, d, q) and its components autocorrelation function (ACF), partial autocorrelation function (PACF), Normalized Bayesian Information Criterion (NBIC), Box-Ljung Q statistics and residuals estimated, ARI (1, 1) was selected as the best model for forecasting annual commercial Chisawasawa catches. We forecast that the commercial Chisawasawa catch would increase to about 1788 tons in 2020from about 785 in 2010. The confidence intervals for the forecasts include zero, which means that we fail to reject the null hypothesis that the fishery has collapsed. This fishery needs urgent attention. We recommend that these models should be developed for other fisheries in Lake Malaŵi.