Selective Breeding to Enhance the Adaptive Potential of Corals

The decline of coral reefs has prompted an emergent field of research on the potential for various biological interventions focused on increasing stress tolerance in corals. Among these is selective breeding, the selection and reproductive crossing of parental stock based on a trait of interest with the goal of enhancing the frequency or value of the trait in subsequent generations. Selective breeding has been applied to a number of commercially and ecologically important species to mitigate the negative effects of climate change, including marine invertebrates and, more recently, corals. Here, we review the process of selective breeding and detail four case studies that have documented the increase of thermal tolerance in selectively bred corals across various life history stages and experimental temperature stressors. These outcomes are supported by a substantial body of literature demonstrating the heritability of thermal tolerance across organisms, including genome-wide association studies and family-specific responses to heat stress. We also highlight some major knowledge gaps and challenges for selective breeding, including the magnitude of possible phenotypic trade-offs and the potential for unintended negative genetic consequences, and discuss how these risks can be mitigated. We conclude by suggesting areas for future study and conservation approaches that can benefit from the integration of selective breeding. Current evidence suggests that selective breeding may be a viable option for supporting the persistence of coral reefs while strong climate change mitigation actions are undertaken.