Shifts in the Benguela ecosystem and recommendations for protecting Namibia’s fishery economy

Abstract

Natural and anthropogenic disruptions in the flow of energy through marine food webs can result in systematic changes which have implications for ecosystem-based fisheries management. A recent biological regime shift in the N. Benguela current has resulted in an alternate stable state in fish abundance. Many of the depleted stocks are considered forage fish, species of fish preyed upon by top predators like large piscivorous fish and marine mammals. I will present three case studies which demonstrate some of the consequences of depleted forage. I will then highlight documented and probable changes to the N. Benguela as a result of depleted forage species. Decreasing abundance of forage fish and increased abundances in jellyfish could inhibit the system from returning to its previous state. In light of these ecological changes, I will examine Namibia’s fisheries management plan and the nation’s dependence upon its fisheries for economic development. I offer short-term adaptive management strategies focused on the restoration of depleted forage fish stocks, and improved development opportunities. I also make recommendations for long-term strategies aimed at an ecosystem-based management perspective with protections for top predators that will likely undergo declines as a result of a lack of forage.