THE POTENTIAL ROLE OF MASS BALANCE MODELS FOR THE MANAGEMENT OF UPWELLING ECOSYSTEMS

Upwelling ecosystems are productive fishing grounds, contributing ∼30% to the world's catch of marine fish. A set of seven trophic mass balance models of productive subsystems of the four largest upwelling areas is used to demonstrate key features of the modeling process and the analysis of the models using some flow network techniques. The models describe trophic interactions in the northern Humboldt Current (4°–14° S), the northern Benguela Current (15°–35° S), the southern Canary Current (12°–25° N), and the California Current (28°–43° N), focusing on different biological regimes in the 1970s and 1980s. The straightforwardness of the method is emphasized as a coherent basis for more sophisticated modeling approaches. One major advantage over more traditional assessment methods is that the fishery is explicitly tied into the full set of species interactions, and its impact can thus be readily compared to that of other piscivores in the ecosystem. This approach consequently allows us to assess the ecological sustainability of a fishery. It therefore addresses the Code of Conduct for Responsible Fisheries recently published by the Food and Agricultural Organization of the United Nations.