Type
Text
Type
Dissertation
Advisor
Chapman, Demian D | Frisk, Michael | Collier, Jackie | Pikitch, Ellen | Feldheim, Kevin.
Date
2013-12-01
Keywords
effective population size, flounder, microsatellite, silverside, sturgeon, White Shark | Fisheries and aquatic sciences
Department
Department of Marine and Atmospheric Science.
Language
en_US
Source
This work is sponsored by the Stony Brook University Graduate School in compliance with the requirements for completion of degree.
Identifier
http://hdl.handle.net/11401/76202
Publisher
The Graduate School, Stony Brook University: Stony Brook, NY.
Format
application/pdf
Abstract
Genetic diversity is the fundamental building block of biodiversity, harboring the adaptive potential of populations. The magnitude of the two main factors eroding genetic diversity, inbreeding and genetic drift, increases as the effective population size (Ne) decreases. Ne describes the number of reproductively mature adults effectively contributing to the next generation. In populations with overlapping generations, the effective number of breeders (Nb). Loss of genetic diversity has long been a concern for terrestrial and freshwater organisms, but traditionally less so for fisheries management due to the paradigm that marine fish populations are large, panmictic and thus resistant to the erosion of genetic diversity. Therefore, despite widespread concern about the loss of marine fish biodiversity, there has been little concern regarding the genetic biodiversity. However, recent studies have discovered that many marine populations are in fact genetically structured and Ne is frequently several orders of magnitude smaller than census population size. Thus, I assessed the genetic diversity, Ne/Nb and levels of inbreeding in four populations of threatened or endangered species under the hypotheses that the genetic diversity of marine fish populations may be eroding as quickly as in some terrestrial animals and that in extreme cases inbreeding may occur. Indeed, evidence of genetic bottlenecks, low Ne/Nb and inbreeding was found in all four species: The Key silverside inhabits small, tidally restricted hypersaline pools. Extreme shifts in allele frequencies over 10+ generations and loss of genetic diversity demonstrate that the colonization of inland habitats resulting in fragmented populations has a significant impact on the genetic diversity of marine fish. Evidence of severe inbreeding was detected in winter flounder, demonstrating that even historically common marine fish can be prone to inbreeding as populations decline. First estimates of the effective number of breeders Nb for three spawning populations of Atlantic sturgeon were determined using juvenile fish captured at aggregation sites in New York Bight. DNA profiling of white sharks demonstrates their heightened vulnerability due to genetic factors. In conclusion, I place these studies within the context of a literature review of the genetic health of marine fish populations and suggest new avenues for research and standard methods for assessing genetic diversity in marine fishes. | 157 pages
Recommended Citation
O'Leary, Shannon Joy, "The Genetic Diversity of Endangered Fishes in the Northwest Atlantic" (2013). Stony Brook Theses and Dissertations Collection, 2006-2020 (closed to submissions). 2139.
https://commons.library.stonybrook.edu/stony-brook-theses-and-dissertations-collection/2139