I think that additional thought should be given to the process involved in getting from initial seeds (small pieces of “corals of opportunity”, gametes harvested during spawning events) to a substantially restored reef, and how each of the steps in the process should be incorporated in the design of the contest and the scoring of the competing teams. Consider the following:
How do you get from initial seeds to a founding population large enough to restore a hectare of reef? The answers will be very different for strategies based on sexual reproduction from gametes, which is currently a lengthy and inefficient process, and asexual nursery-based growth and fragmentation, which can be very efficient for some coral species but not others, and can result in limited genetic diversity. X-Prize guidelines should spell out how much time competitors will have to generate their founding populations, and whether the timing and efficiency of the process will be amongst the scoring criteria. They should also specify whether this will be part of the “demonstration round” only, or also of the final round. In any case, growing enough corals to restore a hectare of reef is going to take a significant amount of time, no matter what the resources are that the competitors can draw on.
Diversity of species and genetic diversity within a species have both been mentioned as scoring criteria. I assume that this will apply to the diversity of the nursery-grown founding population as well as the diversity of the fully restored reef, which are quite distinct metrics. There are many examples of reefs that were restored from a limited founding population, which was then able to recruit other species or genets by providing a favorable environment for larvae to settle. Careful consideration should be given to not being too prescriptive about the diversity of the founding populations, although this could be incorporated into the scoring criteria.
As already mentioned by others, the choice of outplanting sites will have an oversized influence on the characteristics of the restored reefs. Sites that have a degraded existing coral cover are likely to be easier to restore than those without any remaining live corals. Benthic covers of sand, coral rubble, or rocks will require quite different approaches to restoration, by providing very different substrates for outplanting techniques. Sites close to heathy reefs may repopulate more easily. Those affected by adverse environmental conditions will be penalized. If the candidates are solely responsible for picking outplanting sites, it will be very difficult to apply consistent scoring criteria. I would suggest that criteria for choosing outplanting sites, and their influence on scoring metrics, be spelled out in some detail in the X-Prize guidelines. It may even be necessary to include controls managed by the X-Prize and located next to the competitor outplanting sites to provide some level of normalization. The alternative may be for the X-Prize to pick a limited number of sites on which all competitors would have to demo their techniques.
I will return with more detailed comments targeted to the minimum requirements and the scoring criteria.