Impacts of TURFs and marine reserves on fisheries and conservation goals: theory, empirical evidence, and modeling

Unsustainable fishing in marine systems creates fisheries management and conservation challenges, with implications for ecosystem health, livelihoods, economies, and seafood supply. Thus there is a need for management approaches that can support productive fisheries and healthy ecosystems. Property rights, and particularly spatial rights or territorial use rights in fisheries (TURFs), are increasingly proposed as a solution. It has been suggested that TURFs may align fishers' incentives with long-term stewardship, resulting in improved yields and positive conservation outcomes. Here we examined this idea by reviewing existing theoretical and empirical evidence for TURF performance in achieving both fisheries and conservation goals, and find equivocal evidence that TURFs can consistently deliver on this promise. We then explored the potential to improve outcomes by implementing no-take marine reserves with TURFs ("TURF-reserves"). We evaluated theoretical and empirical evidence in the literature and develop a simulation model to examine tradeoffs for achieving conservation and fishery objectives. With our model, we examined different management regimes (e.g., open access vs TURFs), harvest controls within the TURF (e.g., selectivity and harvest rate restrictions), and varying reserve sizes. We found that combining reserves with TURFs does not eliminate the tradeoff between fisheries and conservation goals if the TURF already effectively controls fishing pressure. However, given the results from our literature review, many TURFs may not achieve effective fisheries management. Thus, TURF-reserves may be better able to balance fisheries and conservation goals relative to TURF-only systems, but outcomes will depend on target species mobility, TURF size, and fishing intensity outside the TURF-reserve.