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Title: Integrative approaches for conservation management of critically endangered Nassau grouper (Epinephelus striatus) in The Bahamas
Author: Sherman, Krista Danielle
ISNI:       0000 0004 7232 1006
Awarding Body: University of Exeter
Current Institution: University of Exeter
Date of Award: 2018
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Species conservation is typically founded upon a range of management strategies, which integrate both biological and socioeconomic data. In this thesis, population genetics, acoustic telemetry, spawning aggregation surveys and stakeholder assessments were used to address key knowledge gaps limiting effective conservation management for critically endangered Nassau grouper (Epinephelus striatus) stocks in The Bahamas. A panel of polymorphic microsatellite markers was optimised to assess the genetic population dynamics of more than 400 Nassau grouper sampled throughout the country. Microsatellite data indicate that contemporary Nassau grouper populations in The Bahamas are predominantly genetically diverse and weakly differentiated, but lack geographic population structure. Assessments of changes in effective population size (Ne) show substantive reductions in Ne within The Bahamas compared to historic values that are likely due to natural disturbances. Evidence for recent bottlenecks occurring in three islands as well as an active spawning site, along with higher inbreeding coefficients in two islands were also found, and can be attributed to more recent anthropogenic activities. Collapse of a historically important Nassau grouper fish spawning aggregation (FSA) was supported by both acoustic telemetry and spawning aggregation survey dives. Restriction-site-associated DNA sequencing (RAD-seq) of 94 Nassau grouper was used to explore intraspecific population dynamics, loci under selection and patterns of gene flow in The Bahamas. Genomic assessments of diversity were in accord with microsatellite data and examinations of gene flow support higher levels of connectivity in The Bahamas than was previously suggested. The increased resolution gained from assessments of genomic data support intraspecific population structuring that may be driven by differences in gene flow and putative loci under divergent selection. Telemetry data were successfully used to identify the origins of spawning adults, and support demographic connectivity through migrations between an active FSA in the central Bahamas and home reef habitats within the Exumas and a no-take marine protected area. Stakeholder assessments highlight the complexities of fisheries management within The Bahamas, with key stakeholders often exhibiting conflicting opinions regarding the status of Nassau grouper and the efficacy of management options. However, these groups mutually agree upon the need to better manage remaining Nassau grouper stocks within The Bahamas through science-grounded policies. Synthesis of these studies along with a review of fisheries governance in The Bahamas was used to develop a comprehensive national management plan for Nassau grouper to facilitate better conservation for remaining populations of this ecologically important marine species.
Supervisor: Tyler, Charles ; Stevens, Jamie ; Simpson, Stephen D. Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available
Keywords: Fisheries management ; Population structure ; Genetic diversity ; Microsatellites ; Single nucleotide polymorphisms ; Fish spawning aggregation ; Effective population size ; Connectivity ; Gene flow ; Telemetry ; Marine policy ; Socioeconomic drivers ; Marine protected areas ; Sustainability