Towards the development of environmental indices for the Namibian shelf, with particular reference to fisheries management

The Namibian Ministry of Fisheries and Marine Resources has the task of collecting and providing relevant oceanographic information for management of their fisheries. However, quality information is difficult to provide because of the complexity of the processes involved in the Namibian marine ecosystem. Nonetheless, there are oceanographic data available that can contribute to fisheries management by improving the general understanding of important oceanographic processes related to fisheries. The focus of this paper is on the development of simple environmental indices that can serve as a measurement or proxy of the state or intensity of certain important oceanographic processes or variables for temporal comparison. These indices relate to oceanographic processes such as up-welling, frontal movements, anoxic bottom conditions and biological indicators, which can be updated on a regular basis to provide a long-term perspective of the particular processes to management and marine scientists.