Evaluation of quota management policies for developing fisheries

Losses can be measured as deviations from a desired reference trajectory of quotas that would be taken if there were no uncertainty and are highly dependent on assessments prior to and during development. Simulations of assessment and quota setting under various quota setting rules indicate that variability in relative abundance indices can cause substantial losses, especially considering cumulative effect of early quota errors on later departures of biomass from that needed to produce the desired quotas, even if optimum fishing mortality rate is known in advance. Conservative assessments (low biomass estimates for which there is only a small probability that biomass is actually lower) are favored during development when loss is measured as the relative departure from the best quota for each year. But if loss is measured as absolute departure from the best quota, it is generally better to base the quota on the biomass estimate for which there is nearly a 50% chance that the stock is smaller. Deliberate overfishing (probing) is not favored under either loss measure. Losses can be reduced with minimum biomass surveys and closed areas that directly cushion fishing mortality rates from being more than 50% too low or high.