| Summary: | 15 páginas, 8 tablas, 13 figuras.-- SC WG on Ecosystem Approaches to Fisheries Management The observed changes in the Flemish Cap demersal community since early 1990’s, with cod (Gadus morhua), redfish (Sebastes sp.) and shrimp (Pandalus borealis) stocks fluctuating in opposite directions, in addition to the existing trophic interactions between them, led to the issue of the magnitude of trophic interactions between these commercial species and its implication for population dynamic and fisheries management. In this work, total consumption by cod and redfish, as well as consumption on preys like redfish, shrimp and other species was estimated using a generic bioenergetic model. Changes in feeding habits, growth rates and variations in total predator biomass (cod and redfish) produced changes in consumption at a population level. Variations in the diet were related with changes in prey availability. In turn, redfish consumption by cod and shrimp consumption by cod and redfish seems to have been one of the reasons for variations in population dynamic of these two commercial prey species. Consumption on alternative prey like hyperiids, copepods and other fishes was important and in some cases it was related with the abundance of other main prey like shrimp and redfish. The importance of the abundance of alternative prey for management of commercially exploited prey species is evaluated, as well as the importance of qualitative and quantitative features of interactions between fishing and fish predation for population dynamic and management strategies. Peer reviewed
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