HCNSO Student Theses and Dissertations

Defense Date

7-25-2019

Document Type

Thesis

Degree Name

M.S. Marine Biology

First Advisor

David Gilliam, Ph.D.

Second Advisor

John Fauth, Ph.D.

Third Advisor

Nicole Fogarty, Ph.D.

Abstract

Coral reefs have declined globally due to anthropogenic stressors increasing the frequency and severity of bleaching and disease events. In 2014, a stony coral tissue loss disease (SCTLD) outbreak occurred off the coast of southeast Florida and subsequently spread throughout the region. Data collected by the Southeast Florida Reef Evaluation and Monitoring Project (SECREMP) were used to examine the regional impacts of the disease event on the Southeast Florida stony coral assemblage. A long-term annual monitoring project, SECREMP samples permanent sites along the Southeast Florida Reef Tract (SEFRT) from Miami-Dade County north to Martin County. Analysis of stony coral demographic data from 21 sites revealed regional SCTLD prevalence increased significantly, and significant region-wide declines in stony coral diversity and density were observed. From 2014 to 2018, species-specific susceptibility to the disease were evident, with Meandrina meandritesand Dichocoenia stokesiboth losing > 90% of all live tissue by 2016. The reef building, complexity-contributing species Montastraea cavernosaand Orbicellaspp. lost significant tissue (55% and 70% respectively) as a result of this disease event. Overall, up to 64% of all live tissue was lost and at least 11 of 28 total species were impacted by SCTLD. Of the colonies that suffered complete mortality, many were among the largest individuals in the dataset. Loss of large, sexually mature colonies lowers reproductive capabilities and thus severely inhibits the potential for recovery. Juvenile surveys showed many of the large, structurally complex species had little to no juveniles within the sample sites, while eurytopic generalist species made up more than 76% of all juveniles. This disease event resulted in acute mortality and altered ecosystem function to the point where recovery is uncertain. To facilitate recovery, local resource managers need to understand the severity of the disease outbreak on the coral assemblage and mitigate local anthropogenic stressors.

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