Coral Propagation: Land-based and Offshore Nursery Phase VI

NSU’s land-based nursery has three goals: 1) preserve the genetic diversity of five priority coral species and sexually propagate them to generate corals of high genetic diversity to restore Broward County’s reefs within the Kristen Jacobs Coral Conservation Area; 2) optimize the culture methodology of corals so that production is maximized while production cost, labor and time are minimized; and 3) train new individuals in coral restoration. Significant progress has been made over the six phases of the project, with success hinging on continued research to increase cost-efficiency of NSU’s propagation pipeline and the skills of our staff.

In this phase of the project, NSU’s land-based coral nursery maintained 117 healthy adult colonies: thirty-three Montastraea cavernosa, nineteen Pseudodiploria clivosa, nineteen P. strigosa, nine Orbicella faveolata, seventeen Diploria labyrinthiformis, and twenty Colpophyllia natans. Maintaining corals in aquaria long term requires water quality management, equipment maintenance, and control of disease and pests. In an effort to increase the cost-effectiveness of coral production, we have set up a Tri-annual Coral Spawning Chamber (Tri-ACSC) which will allow us to maximize the use of our space and equipment dedicated to larval culture, settlement and early grow-out, and increase production of corals, without needing to increase broodstock. During this Phase, and after the 2024 spawning, the coral broodstock was moved to the Tri-ACSC room and their annual cycles of temperature, sun and moonlight were shifted to induce spawning in July, January and April. The room previously used for spawning induction was refitted to accommodate 8 conical tanks for larval rearing and 8 raceways for settlement and early grow-out. 

NSU’s aquaria are outfitted with highly precise temperature and artificial lighting control systems to assure the survival, growth and highly synchronized sexual reproduction of corals ex situ. The adult coral colonies held in NSU’s recirculating aquaculture systems produced hundreds of thousands of larvae that were reared under optimized lab conditions at NSU or donated to other coral nurseries for rearing. Larval settlement and early growout was still impaired by high settler density caused by insufficient space dedicated to these phases; we expect this constraint to be overcome next year as we will have 8 raceways available for the settlement and early grow-out of each species, instead of just 3 raceways for all species. Two hundred and seventy three corals from two priority species produced during the previous phase of this project (2023 spawning) were moved into NSU’s offshore coral nursery for acclimation prior to being outplanted on local reefs.