Under the "assisted colonisation" scenario, suggested as one way to ameliorate the possible impacts of climate change, coral populations and/or species adapted to warmer temperatures would be translocated onto cooler, but warming, southern reefs. Through interbreeding, warm-adapted genes would then be incorporated into the receiving population, possibly increasing resilience to rising temperatures.
In a new project, co-funded by the GBR Foundation, AIMS conducted a pilot study to address the following questions: (1) Can translocated corals interbreed with native corals? (2) Does inter-population breeding result in increased fitness in regional hybrids compared to purebred offspring?
Increased fitness in regional hybrids may occur as new and beneficial genes and/or gene combinations are introduced into the receiving populations. This is a desired outcome of the assisted colonisation strategy. Alternatively, the fitness of hybrid offspring may be lower than that of the offspring of the native corals. If this weakening of genetic stock was to occur as a result of translocation it would clearly not be a desirable conservation outcome.
The results obtained so far show that Acropora millepora and A. tenuis corals from Orpheus Is (central GBR) can interbreed with colonies from the Keppel Islands (southern GBR) under laboratory conditions, producing normal-looking offspring.