Ending Overfishing Through Use of Annual Catch Limits

The Magnuson-Stevens Act (MSA) provides the foundation for management of marine fisheries in the US.  In 2007, the MSA was amended to contain a provision that required establishment of Annual Catch Limits (ACLs) in all fisheries at a level “such that overfishing does not occur”.  Further, these ACLs are required to be accompanied by accountability measures and cannot be set above the fishing level recommendations (aka Acceptable Biological Catch, ABC) of the Scientific and Statistical Committees of the regional Fishery Management Councils.  In 2009, the National Standard 1 Guidelines were updated by NOAA Fisheries to provide more specific guidance for implementation of the MSA provisions.  In particular, the NS1G specify that there be a risk-neutral calculation of the level of catch that would be the best estimate of the overfishing level, a risk-averse calculation of the SSC’s ABC to take into account scientific uncertainty in the estimate of OFL, and further adjustments to catch targets to take into account management uncertainty in the ability to control annual catch to not exceed the ACL.  Where stock assessments are able to provide a reasonably comprehensive accounting of the uncertainty in assessment forecasts of OFL, the ABC level can be calculated in order to implement a specified probability, not to exceed 50%,  of overfishing taking into account the degree of uncertainty in the OFL.  There are two major implementation challenges.  One is the development of risk or trade-off analyses to inform the decision with regard the best choice for the acceptable probability of overfishing.  The other is development of suitable proxies for immeasurable quantities in fisheries that lack sufficient information to conduct a full assessment and suite of probability calculations.  All Fishery Management Councils in the US are nearing completion of fishery plans to implement ACLs to transparently identify, and thus prevent, overfishing.