Translating the terrestrial mitigation hierarchy to marine megafauna bycatch

In terrestrial and coastal systems, the mitigation hierarchy is widely and

increasingly used to guide actions to ensure that no net loss of biodiversity

ensues from development. We develop a conceptual model which applies

this approach to the mitigation of marine megafauna bycatch in fisheries,

going from defining an overarching goal with an associated quantitative

target, through avoidance, minimisation, remediation to offsetting. We

demonstrate the framework's utility as a tool for structuring thinking and

exposing uncertainties. We draw comparisons between debates ongoing in

terrestrial situations and in bycatch mitigation, to show how insights from

each could inform the other; these are the hierarchical nature of

mitigation, out-of-kind offsets, research as an offset, incentivising

implementation of mitigation measures, societal limits and uncertainty. We

explore how economic incentives could be used throughout the hierarchy to improve the achievement of bycatch goals. We conclude by highlighting the

importance of clear agreed goals, of thinking beyond single species and

individual jurisdictions to account for complex interactions and policy

leakage, of taking uncertainty explicitly into account, and of thinking

creatively about approaches to bycatch mitigation in order to improve

outcomes for conservation and fishers. We suggest that the framework set

out here could be helpful in supporting efforts to improve by catch

mitigation efforts, and highlight the need for a full empirical application to

substantiate this.