Methods to improve the success of SCTLD-susceptible coral species outplanted for restoration: From lab to nursery to reef

In this project, researchers evaluated methods to increase the growth and survivorship of fragments and recruits of four species of SCTLD-susceptible species commonly used for restoration in Florida. The growth and survivorship of DLAB and MCAV were enhanced by feeding while ex situ prior to outplanting, but feeding did not influence fish predation rates. The benefits of feeding on growth and survivorship were higher for smaller corals. Coral size had a positive influence on survivorship both ex situ and after outplanting, indicating that keeping corals within nurseries until they reach a threshold size of at least 4 cm in diameter is highly beneficial. Feeding corals ex situ allows for this size threshold to be reached faster. We did not find a direct relationship between feeding and lipid or protein content but a larger sample size or longer feeding periods may be needed to detect such changes. Both MCAV and DLAB showed high survivorship both in situ and ex situ. We found that when growing corals from larvae, the optimum number of recruits to be reared on a single plug is 2-10. This density maximizes both survivorship and the number of surviving genotypes. Through the use of specially designed cement coral bases, we concluded that protection from fish predation is only efficient when fish are prevented from reaching the outplanted PCLI corals through the use of plastic canopies or by embedding the coral fragments 1 cm into the base. The treatments that only provided partial physical protection were ineffective at reducing predation.