Maximizing genetic diversity in coral restoration projects

As natural coral populations decline, thousands of outplanted corals are poised to dominate reefs in the hardest-hit areas, such as the Florida Keys. Genetic management plans are urgently needed to prevent unintended erosion of genetic diversity in managed populations. Drivers of genetic diversity loss include limited nursery genets available for outplanting or that these genets were reared from crosses among a limited number of parent genets. Existing data indicate that captive rearing of coral larvae can impose substantial genetic bottlenecks that result in closely related cohorts. Thus, questions arise about how to safeguard genetic diversity and optimize the adaptation potential of restored populations. What is the optimal ratio of asexually propagated colonies to sexually produced coral recruits at each site? What breeding scheme should be used if a limited number of donor genets are available? Should breeding be selective to achieve a shift in phenotypes such as thermotolerance at the risk of losing genetic diversity? Population viability analyses (PVA) can answer some of these questions, but current models need to be modified to resolve the most pressing issues. This chapter discusses omics methods to determine genetic diversity of corals and their symbionts and outlines strategies to achieve genetic diversity goals.