Ocean recoveries for tomorrow's Earth: Hitting a moving target.

BACKGROUND Ocean defaunation and loss of marine ecosystem services present an urgent need to recover degraded ocean ecosystems. Growing scientific awareness, strong regulations, and effective management have begun to fulfill the promise of recovery. Unfortunately, many efforts remain unsuccessful, in part because marine ecosystems and human societies are changing. Rapid shifts in environmental conditions are undermining previously effective recovery strategies. Moreover, divergent perceptions of recovery exist. Efforts toward reversing marine degradation must address the dynamic social-ecological landscape in which recoveries occur, or forever chase a moving target. ADVANCES Recovery efforts of tomorrow will require institutional and tactical flexibility to keep pace with a changing ocean, and an inclusive concept of recovery. Further, vital population-level efforts will be most successful when complemented by a broader ecosystem and social-ecological perspective. In this Review, we provide a synthesis of ocean-recovery goals as moving targets and highlight promising steps forward. (i) Society can reenvision a more inclusive definition of recovery by recognizing a multiplicity of recovery goals. While acknowledging the priority of basic conservation imperatives, successful recoveries can encompass a range of outcomes in the space between minimum ecological viability and maximum carrying capacity. (ii) Research can help anticipate future recovery dynamics and identify pathways toward resilient ecosystems. Ongoing advances are improving our ability to predict the effects of environmental change on ocean productivity and to calibrate recovery targets to changing conditions. As a complement to predict-and-prescribe methods, research can also point the way toward robust approaches in the face of irreducible uncertainty. (iii) Policy-makers can embrace nimble approaches to keep pace with change and integrate governance to operate seamlessly from local to regional scales. Future recovery frameworks should enable rapid response to changing conditions and allow fluid coordination among institutions. Such policies will mitigate conflicts between recovery objectives at different spatial scales and better integrate local knowledge and traditional cultural practices around recovery. OUTLOOK Application of these principles will help to reshape recovery of marine ecosystems, yet important scientific questions and societal barriers remain. For researchers, interactions among multiple components of environmental change will test the limits of prediction in tomorrow’s ocean. For managers and policy-makers, operationalizing an inclusive definition of recovery organized around social-ecological resilience will prove more challenging than simply recrafting recovery policies with new recovery metrics. Rather, this process will involve designing policies that align incentives for disparate human actors toward coherent recovery goals. Looking ahead, emerging technologies can enable interventions necessary to match the scale of the challenge. It remains possible to recover lost biodiversity in the ocean and to enhance the delivery of marine ecosystem services. Doing so will require a strategic, nuanced, and flexible conceptualization of ocean recoveries that can keep pace with ever-changing physical, ecological, and social environments.