Harvest control rules (HCRs) are the operational component of a harvest strategy, essentially pre-agreed guidelines that determine how much fishing can take place, based on indicators of the targeted stock’s status. HCRs range from basic, constant catch strategies—under which catch levels do not change—to complicated, multistep rules that set allowable catch based on triggers.
Empirical HCRs: Indicators come from one or more direct measures of stock status
Model-based HCRs: Indicators are based on models
Stock status can be represented graphically by what is known as a Kobe plot. The example below shows a basic HCR. The fishery’s ideal state is green, its cautionary state is yellow, and the state to avoid is red. The HCR has the following specifications:
Harvest control rules provide more benefits than the traditional approach of conducting stock assessments and then negotiating fishing limits or quotas. Pre-agreed management actions taken in response to stock status indicators increase the efficiency and transparency of management. They also help avoid costly and difficult political negotiations.