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Development of microsatellites for the bay scallop, Argopecten irradians (Lamarck), with application to evaluating restoration

UNCW Author/Contributor (non-UNCW co-authors, if there are any, appear on document)
Elizabeth M. Hemond (Creator)
Institution
The University of North Carolina Wilmington (UNCW )
Web Site: http://library.uncw.edu/
Advisor
Ami Wilbur

Abstract: Due to the threats of pollution, overfishing, and harmful algal blooms, populations of the bay scallop have become jeopardized throughout this species range. Proactive restoration efforts have been undertaken in Florida, North Carolina and New York with varying degrees of success. However, the interpretation of the impacts of restoration activities are complicated by a lack of direct assessments. The objective of this study was to evaluate the potential of microsatellite markers and multi-locus assignments in genetic assessment of bay scallop restoration. Five-hundred and thirteen clones from a genomic library were sequenced and yielded 93 loci, of which five were developed for use in this project. These five loci exhibited relatively high variation (8-25 alleles/locus) and adhered to expectations of Mendelian inheritance and Hardy-Weinberg equilibrium. The parents and offspring of a hatchery spawn were genotyped with the microsatellites and revealed a loss of allelic diversity in the F1 generation. Parentage analysis indicated highly biased contribution with over 87% of the offspring whose parentage was identified being attributable to a single pair of scallops. Samples of three regional populations of scallops (Florida, North Carolina and New York) were genotyped using nine loci and exhibited significant genic differentiation. The highest level of differentiation was found to occur between Florida and the Atlantic samples (FST=0.1137). Assignment of scallops to regions indicated high power of assignment between Florida and Atlantic populations, but low power between New York and North Carolina populations. In addition, Bayesian clustering indicated population structure between Florida and the Atlantic samples, but none between New York and North Carolina. Microsatellite analysis and assignment tests were applied to an assessment of restoration in Pine Island Sound following a 2003 release of 1.5 million larvae from a hatchery spawning of twelve scallops from Anclote Estuary. Scallops sampled from the wild populations in Pine Island Sound, Anclote Estuary and Steinhatchee (a site north of Anclote Estuary) were used to define potential source populations. Little to no differentiation between these populations was observed, and assignment analyses correctly identified the origin of these scallops less than 50% of the time. Assignment of a sample of post-restoration scallops from Pine Island Sound was inconclusive as the assignment tests were unable to distinguish between potential source populations. The utility of microsatellites and multilocus analysis in restoration depends on moderate differentiation between the restoration stock and the wild population, as well as appropriate genetic characterization of the restoration stock sample.

Additional Information

Publication
Thesis
A Thesis Submitted to the University of North Carolina at Wilmington in Partial Fulfillment of the Requirement for the Degree of Masters of Science
Language: English
Date: 2009
Keywords
Bay scallop, Bay scallop--Conservation, Bay scallop--Genetics, Microsatellites (Genetics), Scallop culture
Subjects
Bay scallop
Scallop culture
Microsatellites (Genetics)
Bay scallop -- Conservation
Bay scallop -- Genetics