A number of European fishing fleets have been regulated through a combination of quota and effort (sea days) controls since 2004. These two regulation schemes are however interrelated, i.e. a given quota limit will necessarily determine the effort used, and vice versa. A bioeconomic feedback model is presented that takes into account this causality between effort and harvest control, and switches back and forth between these two regulation schemes depending on which is the binding rule. The model is based on biological stock projection, and quotas are set using the Pope approximation, while an economic production function is used to estimate harvest when effort is binding. The economic response of the fleet is modelled through a dynamic investment/disinvestment module that evaluates the change in fleet capacity given the economic outcome of the fishery. A simple example is presented for Danish seiners catching cod in the North Sea.

The model has been constructed as part of the 6'Th framework project ‘Operational Evaluation Tools for Fisheries Management Options (EFIMAS)'.

Emneord: LIFE: Combined Quota and Effort Control, Bio-Economic Modelling, FLR (Fisheries Laboratory in R)