Conservation Genetics Of Commercially Exploited Fishes With Case Studies On Leopard And Nassau Grouper

Overfishing is contributing to significant declines in marine species worldwide. Here, I evaluated the contribution of genetic data to enhancing conservation and fisheries management of commercially important fishes. First, I conducted two empirical population genetics studies on groupers that aggregate to spawn. I evaluated population structure of Nassau grouper (Epinephelus striatus) across the Caribbean Sea using mitochondrial DNA, microsatellites and single nucleotide polymorphisms (SNPs). Results suggested ocean currents and long distance migrations of adults to spawning sites may contribute to restricted gene flow and regional genetic differentiation among subpopulations, making it less likely that larvae settle beyond catchment areas of spawning sites. Regional patterns of genetic differentiation warrant international collaboration, standardizing fisheries management and conservation initiatives among countries within genetically isolated clusters. I then evaluated population structure of Leopard grouper (Mycteroperca rosacea) in the Gulf of California using mitochondrial DNA and microsatellites. I observed genetic differentiation and asymmetrical connectivity among subpopulations of M. rosacea, with divergence of lineages dating to the late Pleistocene and Holocene. Findings suggest a combination of marine reserves, catch quotas, and seasonal fishery closures as a potential management strategy for M. rosacea in the Gulf of California. Finally, I conducted a meta-analysis of 386 empirical genetics studies on marine and diadromous fishes in order to evaluate the implications of weak or strong population structure on the implementation of fisheries management. Quantitative adjectives used to describe varying magnitudes of genetic differentiation possessed statistically different mean FST values in studies utilizing mtDNA, microsatellites and allozymes. Additionally, mean FST values across stock management strategies were statistically different from one another. Results have major implications for standardizing reporting of metrics of genetic differentiation across empirical population genetics studies focusing on and prescribing stock management strategies for commercially important fishes