| dc.description.abstract | Harvest control rules (HCR) are sets of well-defined rules that can be used for determining annual fish catch quotas or effort. If a management policy can be expressed as a HCR, then the HCR provides means to determine the total allowable catch unambiguously. In order to improve certain aspects of the performance for these rules (higher yield, lower variability of yield, less risk of decreased population biomass), strategies of increasing complexity have been suggested for fish stocks both in Europe and in North America. But is this complexity necessarily better? Are simple strategies outdated? “Traditional” harvesting strategies (i.e. constant harvest rate, fixed quota and constant escapement strategies) are simple HCRs with only one control parameter (i.e. target harvest rate, catch and escapement, respectively). “Complex” harvest control strategies are here defined as a multi-parameter HCR. In this study, three criteria (average catch and its coefficient of variability and risk of population abundance below a minimum acceptable level) are used to judge the performance of traditional and complex HCRs, utilizing a stochastic age-structured population model that mimics the dynamics of fish populations. Even though the three HCRs performed rather similarly in the different simulations, the simplest HCR achieved the best results overall. The HCRs are further evaluated against each other, paying particular attention to the tradeoffs among the performance criteria and also relating them to bio- and socioeconomic issues. Keywords: harvest control rules, harvesting strategies, single-parameter rule, multi-parameter rule, stochastic population models, noise, age-structured models | en_US |
