Bycatch in marine fisheries is the leading human-caused source of mortality for marine mammals. It has contributed to the decline and in some cases extinction of marine mammal populations and species.
There is a growing need for better assessment of marine mammal bycatch in fisheries, which is set to increase even more with the introduction of the recently implemented Import Provisions of the United States Marine Mammal Protection Act.
A new paper by Wade et al. lays out a framework for managing bycatch of marine mammals, providing guidance on how to: plan a bycatch assessment (1), collect appropriate data (2), conduct an assessment of bycatch (3), and use the results of the assessment to guide bycatch reduction (4). The paper also provides an overview of available mitigation techniques for bycatch reduction.
The framework first stresses the need to plan for an assessment of bycatch, by identifying fisheries that may interact with marine mammal populations, initially characterizing the marine mammal community, and prioritizing data collection. Then, the framework emphasizes the need to collect appropriate data by quantifying marine mammal bycatch as well as the abundance of marine mammal populations. The framework also lays out ways to conduct an assessment of bycatch by using a stock assessment process and PBR reference point or alternative methods. Finally, the framework provides guidance on how to use the results of the assessment to guide marine mammal bycatch reduction, by identifying high priorities for bycatch reduction, mitigating marine mammal bycatch, and how to mitigate without assessment.