Distributive equity and wellbeing implications of catch shares: Bayesian influence diagram of the US IFQ scallop fishery

Abstract

Catch shares have been shown to have many benefits, including eliminating the race to fish, increasing profitability, and supporting stock sustainability. However, without express measures to prevent inequities, catch shares may result in socially undesirable outcomes. Currently, data and methods to evaluate equity and wellbeing outcomes are lacking, contributing to questions about if and how outcomes may be improved. Based on a review of US catch share programs and using the US Atlantic sea scallop individual fishing quota program as a case study, we developed a Bayesian belief influence diagram to evaluate management options to improve distributive equity and associated wellbeing outcomes. The influence diagram evaluated an intervention to expand community quota ownership, which was deemed the most desired and plausible option through expert interviews, on eight wellbeing-related dimensions. The model and the intervention scenarios were developed and evaluated by fishery management and industry stakeholders and utilized a combination of existing and new data obtained from a harvester survey. Findings suggest that an expansion of community quota ownership can improve several dimensions of wellbeing but may not improve access and affordability of quota shares; suggesting the central roles played by quota lease and transfer markets. The study highlights the utility of using a participatory approach to overcoming data limitations and further advances how influence diagrams can be used to holistically evaluate wellbeing outcomes under various management changes.