Abstract

The recently developed method of microfragmentation promises advancement in the cultivation of massive coral species in land and field-based nurseries, however, previous efforts have been labor intensive and/or required costly land-based facilities. The direct outplant of microfragments from massive coral species onto the reef could reduce the time, upkeep, and costs associated with coral restoration projects by eliminating the intermediate lab or ocean-based nursery phase. To determine whether directly outplanting microfragments onto the reef is feasible, we tested the fusion, survival and growth of microfragments of two common Caribbean corals: mustard (Porites astreoides) and finger (P. porites). In June 2019, 98 clusters of four microfragments (P. astreoides: 47, P. porites: 51) were attached to 8 Biorock structures using epoxy (13-15 clusters per Biorock) within the BahaMar Resort snorkel area (Nassau, The Bahamas). After 0.5 yr, microfragment survival was 95.7% for P. astreoides and 93.1% for P. porites. Microfragment survival decreased to 82.4% for P. astreoides and 79.5% for P. porites after 1.5 yr. Full fusion (all 4 microfrags fused) at the 0.5 yr to 1.5 yr marks were 29.8% and 31.9% for P. astreoides and 0% and 6% for P. porites. Clusters of P. astreoides initially showed an increase in mean total area before trending down; while P. porites clusters trended down for 1.5 yr. After almost 4 yr outplant survival was 75.3% for P. astreoides and 78.6% for P. porites. Although preliminary results showed that P. astreoides may be a more favorable species for use in microfragmentation, after 4 yr P. porites survival is higher and new colonies, presumably from outplanted corals, have colonized the Biorock domes. Future work with microfragmentation should continue to optimize the design and methods, such that the size