Bioeconomic Modelling of the Namibian Rock Lobster

Research PaperThe purpose of this study is aimed at developing a simple bioeconomic model of the Namibian rock lobster fishery, with the main objective being to incorporate economics into fisheries management in order to estimate the potential economic benefits that could accrue to the fishery given efficient management. The complex nature of fisheries requires the integration of resource biology and ecology with the socio-economic and institutional factors that affect the behavior of fishermen and policymakers. Four surplus production (equilibrium) models were initially run, out of which only one model provided reasonable results. The surplus production model implies that the growth in the fish stock is surplus to that required to keep the population at the same level. The four models that were run are two logistic models, the Schaefer model and the Schnute model, and two exponential models, which are the Fox model and the Clarke, Yoshimoto and Pooley model, which is a modified version of the Fox model. In an attempt to obtain results from a logistic model, one was run through SHAZAM, and the results were used to construct a logistic model for comparison. Both the exponential and logistic bioeconomic models estimated higher levels of biomass accompanied by higher levels of yield and profits, then is currently the case in the fishery. The exponential model estimated a lower level of effort at the maximum sustainable yield than the recorded effort levels in 1998, while the logistic model estimated a higher level of effort at the maximum sustainable yield level