Award: OCE-1801866

Some of the major reef-building coral species in the Caribbean haven't successfully reproduced sexually for decades, and it is unclear how populations of these key species are maintained in the absence of sexual reproduction. It is possible that coral populations are being maintained by storm-induced fragmentation: a storm could break fragments from a large coral colony, which then could grow into the reef to become new colonies. However, no studies to date have investigated whether hurricanes can cause massive boulder species to fragment and that such fragments can survive. Here, we explored these questions in the aftermath of the hurricane Irma in the Florida Keys. We have mapped and collected samples of every large coral and every coral fragment along three 10-m transects at one nearshore and one offshore reef in the Florida Keys, two weeks after the hurricane Irma. The same transects were also surveyed six and twelve months later, to assess survival of the fragments. To confirm species identity and investigate clonal structure of the fragments, DNA was extracted from 452 samples and analyzed using a cost-efficient genotyping technique developed in our lab. We found storm-generated fragments of 14 different coral species, including two massive boulder species: Orbicella annularis and Orbicella faveolata. Unexpectedly, nearly all these fragments survived on the reef for at least 12 months after storm-induced fragmentation. Overall, our results confirm the role of storms in asexual reproduction of massive boulder corals in the Florida Keys. Last Modified: 03/09/2020 Submitted by: Mikhail V Matz