AN ECOSYSTEM MODEL OF FISHERIES AND NUTRIENT ENRICHMENT

 

Economic models of fishery largely ignore the linkages to lower trophic levels. In particular, environmental data and other bottom-up information is widely disregarded. Nor are changes in physical environment (bottom-up) alongside both exogenous and endogenous environmental effects included in the general ecosystem models. The objectives of this paper are modeling the impacts of nutrient enrichment on fisheries; particularly the impacts on consumer stocks and the fisheries based on these stocks are presented. We consider an aquatic ecosystem with four components: producers (autotrophs), consumers (herbivores, carnivores), nonliving matter and pollution sources. The interactions between nutrients-producers, producers- consumers are assumed following the Holling type II functional response. Pollution sources cause excess nutrients which linked to increase primary productivity, hypoxia and anoxia. Consequently, consumer stocks are indirectly affected by pollution sources. Our model simulates these processes in the ecosystem.