Communicating uncertainty in quota advice: a case for confidence interval harvest control rules (CI-HCRs) for fisheries1

Multi-annual management plans are important tactical arrangements to support upper-level marine resource policies in many countries. The newly reformed Common Fisheries Policy in the EU reiterates the role of management plans, supported by the development of harvest algorithms, commonly called harvest control rules (HCRs). Current HCRs for most commercially important fish stocks in Europe and Norway depend on point estimates of the size of the spawning stock biomass (SSB) and level of fishing mortality (F) to dictate the scientifically recommended total allowable catch (TAC). When annual TAC advice from the ICES Advisory Committee, for example, is based on a point estimate for SSB, the propagation of uncertainties (assessment models of varying complexity, variable data sources, and variable degrees and structures of random and systematic errors) and subjective expert decisions is contained, at best, in an annex of the official ICES advice document. TAC advice given as an exact number (sometimes specified ...