Evaluating Conservation Reference Points and Harvest Strategies in Pacific Herring and the Impact of Dispersal

摘要

The risk assessment framework of Fu et al. (2004) for evaluating reference points for resource management was applied to the five Pacific herring Clupeapallasi stocks within the metapopulation managed in British Columbia, Canada. A suite of performance indicators reflecting both fisheries and conservation considerations were investigated as a basis for evaluating appropriate harvesting policy for this resource. The existing policy of a 20% annual removal rate as long as the forecast abundance exceedsthe fishing threshold (25% of estimated unfished equilibrium spawning biomass) was determined to be precautionary, given the performance indicators, for all but the Queen Charlotte Islands stock. However, it was noted that dispersal rates of herring among the five stocks has a dramatic impact on the estimate of stock resilience and consequently on the appropriate stock reference points. It is recommended that the effect on harvest policy of the magnitude and consistency of dispersal be further investigated as part of any policy review.