Fig. 2. Atlantic cod biomass profile calculated from a virtual population analysis (solid line) and optimal biomass profiles calculated by maximizing net present values at discount rates of 0% (solid circles) and 20% (open circles). Modeling was performed using the Ecopath software suite (www.ecopath.org). A Monte Carlo procedure was used to vary basic Ecopath parameters (biomass, production and consumption) for all species groups (n = 20, CV = 0.2). Error bars indicate ±1 standard deviation around the mean. This ecosystem model was adapted from Ainsworth and Sumaila (2005).