An ecosystem framework for fisheries management in the southern Benguela upwelling system

A "four-step framework" for applying ecosystem approaches to fisheries management in the southern Benguela is proposed. First, static ecosystem models can be used to highlight important interactions by assessing the net trophic impacts of each species on all the others. Second, using a dynamic simulation approach, indicators quantifying interaction strength and functional impacts can provide information on the size of impacts on ecosystem components when a group is overfished. Third, dynamic simulations can suggest some possible short- and long-term ecosystem effects of altered fishing under strategies developed and selected using standard single-species models. Finally, the net combined ecosystem effects of the revised strategies for all fisheries in the ecosystem need to be considered together. For this to be accomplished, overall objectives for regional fisheries management, objectives for each fishery, and non-consumptive objectives need to be clearly stated and carefully considered in the provision of advice in an ecosystem context. A selected theoretical fishing strategy is examined to explore the possible ecosystem effects of implementing an option such as this in the southern Benguela ecosystem.