By: Rachel Pausch, Research Associate, CIMAS/SEFSC

NOAA Southeast Fisheries Science Center’s Benthic Ecology Assessment and Research Unit is excited to announce the initiation of our final phase of experimental outplanting with Coral Restoration Foundation. In the last month, Coral Restoration Foundation and our divers planted 864 elkhorn coral fragments across three reefs in large clusters resembling “thickets.” Elkhorn thickets are made up of numerous coral colonies that grow closely together, eventually forming an intricate branching framework. Thickets and other seafloor creatures (think sponges, sea fans, etc.) combine to make up what we picture as a reef. Historically abundant in the upper Keys, elkhorn coral thickets provide essential fish habitat, which helps the reef and humans alike, as well as baffle storm energy and protect our coastline. Unfortunately, live coral thickets have almost disappeared locally, so restoring them in the best way possible was the motivation for this study.

We focused our study objectives on the genotypic diversity of our thickets. A “genet” refers to a group of genetically identical individuals, and the genotypic diversity of a thicket, or how many different elkhorn coral genets there are, can impact its survival. More diverse reefs better resist the effects of stress, whether that stress be natural or man-made, and higher diversity also means our corals can spawn together to make more genets.

Thickets can consist of one genet, or many, and we placed individual corals of differing genets a few different ways: some thickets with two genets separated into groups, then randomly mixed, and some with eight genets grouped and others mixed. While diversity on the reef is great, some genets can actually compete for space and hinder others’ growth, so we’re trying to get a handle on the best way to place individuals when outplanting in these large layouts. We also want to see if there’s any difference in performance between thickets made up of two genets versus eight. We’ll be tracking these plots for associated fish communities and coral cover growth. All of this is possible thanks to the efforts of Coral Restoration Foundation; we’ll keep you updated on what we find!