Defense Date

8-7-2024

Document Type

Thesis

Degree Type

Master of Science

Degree Name

Marine Science

First Advisor

Joana Figueiredo, Ph.D.

Second Advisor

David Gilliam, Ph.D.

Third Advisor

David Smith, Ph.D.

Keywords

sexual recruits, predation, survival, growth

Abstract

Over the past few decades, increasing frequency and severity of direct and indirect anthropogenic stressors have resulted in reef degradation and decreased coral cover and diversity. In South Florida, coral propagation ex situ has gained popularity as a means to restore coral cover. Outplanting sexually propagated corals on the reef is particularly important as it contributes to greater genetic diversity and potentially overall reef resilience. However, these corals typically experience high levels of predation following outplanting, significantly reducing coral survival, and thus constitute a major bottleneck to the success of restoration efforts. This study assessed if simulated predation events on sexually propagated coral juveniles prior to deployment offshore (hereafter termed outplanting) can prime them to generate a physical and/or chemical anti-predatory response mechanism. Sixteen-eighteen month old (4.8-47.6mm diameter) juveniles from six species (Colpophyllia natans, Diploria labyrinthiformis, Montastraea cavernosa, Orbicella faveolata, Pseudodiploria strigosa, and Pseudodiploria clivosa) grown at NSU’s ex situ nursery were used in this study. The juveniles of each species were divided into two groups: a group where individuals were poked with a needle 2 and 4 days prior to outplanting, and a control group where individuals were not exposed to simulated predation. Following that, both groups were outplanted to NSU’s in situ nursery, with half of each group being either cemented to modules or fastened to a tree. Outplants were monitored on days 7, 18, 34, and 81. The effectiveness of simulated predation and in situ grow-out structure on the post-outplant survival and growth of the coral juveniles was assessed. Corals cemented on modules had significantly higher survival rates than those attached to trees, with modules showing 59% survival compared to 53% for trees after 81 days. Coral growth varied significantly over time, but no differences in growth were found between poked vs. unpoked corals or between different nursery structures. Initial coral size influenced predation outcomes, with smaller corals being less likely to be predated but having lower survival if predated.

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