Managing expectations for breeding “super corals”

As climate change intensifies, a primary role of coral restoration is to maintain genetic diversity and ecosystem function while preventing species extinction, at least until global measures to slow the rate of climate change take effect. Recently, the idea of selectively breeding corals with higher heat tolerance (sometimes called “super corals”), and using them to repopulate reefs, has gained wide attention. We outline several reasons why selective breeding for heat tolerance alone is unlikely to yield corals that could be used universally for restoring natural reefs. We propose a managed breeding strategy where a range of traits is considered when choosing corals for breeding and where success is more likely when young offspring bred for these traits are exposed to natural selection in the wild, rather than to artificial selection in nurseries or tanks. However, as extinction risk increases, managing to increase population size becomes the primary goal and all causes of mortality may need to be minimized. In light of these considerations, there is an urgent need to formulate genetic management plans that consider demographic and genetic information for each population under restoration.