Evaluation of management tools for Australia's South East Fishery.3. Towards selecting appropriate harvest strategies

Abstract

The performance of a set of harvest strategies is evaluated for four of the species in Australia's South East Fishery relative to the objectives for the Australian Fisheries Management Authority. Harvest strategies based on the Integrated Analysis method of stock assessment are found to outperform those based on trends in catch rate. Harvest strategies where the target level of fishing mortality aims at stabilizing the spawner biomass at some pre-specified fraction of its pre-exploitation level appear to outperform those that set Total Allowable Catch (TAC) based on estimates of F MSY. The harvest strategies considered are robust to many of the types of uncertainties considered. The factors that influence performance to the greatest extent include the amount by which landed catches are limited by market demands, the depletion of the resource when the harvest strategy is first applied, the variation in recruitment and productivity. Fairly tight limits can be placed on how much the TAC can be varied from one year to the next and any minimum TAC levels should be low. There appears to be little benefit from conducting assessments (and changing TACs) frequently.