Growth and Survival of Sexually Propagated Land-Reared Brain Corals During an Intermediate Offshore Nursery Phase

Growth and Survival of Sexually Propagated Land-Reared Brain Corals During an Intermediate Offshore Nursery Phase

Alvin Sherman Library

Florida’s Coral Reef has degraded from significant stony coral loss due to global and local stressors, including heat stress, disease, and coastal development, leading to reduced natural coral recruitment. Assisted sexual propagation in land-based nurseries can increase the number of genetically unique corals available for restoration efforts. A grow-out phase, in which land-reared corals are placed into an offshore nursery before outplanting on the reef, is often employed to allow corals time to grow and acclimate to the ocean environment. However, research on the performance of recruits within offshore nursery settings remains limited. Here we examine the growth and survival of Diploria labyrinthiformis, a reef-building brain coral that has significantly declined in abundance, largely from stony coral tissue loss disease. In May 2024, 140 recruits were deployed into Nova Southeastern University’s offshore nursery. Images of the recruits were taken at one week, one month, three months, and six months postdeployment to assess survival and planar live tissue area. After six months, the survival rate of D. labyrinthiformis was 67.9% (95/140 individuals). On average, recruits experienced a 331.1% increase in size, suggesting positive growth trends within the nursery. Among surviving recruits, growth was variable, with a mean net growth of 1.1 cm² , ranging from 0.07 to 3.2 cm² . These findings demonstrate that offshore nurseries provide a critical grow-out phase before outplanting, but further research is necessary to discover which factors are contributing to mortality and how the corals will survive once outplanted onto the reef.