EXPLORING THE ROBUSTNESS OF THE CURRENT TOOTHFISH SPP. HARVEST CONTROL RULES AND POTENTIAL EXPLOITATION RATE-BASED ALTERNATIVES

In this paper a simple biomass dynamic population model is used as a paradigm for the dynamics of toothfish spp. in the CCAMLR area. This model underpins a management strategy evaluation framework where the process of stock assessment, TAC calculation and implementation and potential changes in future toothfish productivity (continuous and regime-based) are all simulated. The robustness of the current harvest control rule employed for assessed stocks of toothfish spp. in the convention area is explored with particular attention given to levels of biomass depletion (initial conditions), assessment precision, time-horizon, implementation error and future changes in productivity. An alternative control rule, using target and limit exploitation rates not biomass depletion levels and shorter time-horizons is explored and subjected to similar simulation testing.