Graduation Year

2013

Document Type

Thesis

Degree

M.S.

Degree Granting Department

Geography, Environment and Planning

Major Professor

Steven Reader

Keywords

Centrarchid, genetics, microsatellite, parentage, unnatural selection

Abstract

Advances in molecular technologies have provided conservation biologist with the opportunity to quantify the genetic structure of a population and, in turn develop management guidelines and policies aimed at preserving the genetic diversity of fish stocks challenged by human activities. This thesis examines the status of genetics as applied to the management of freshwater fisheries by state natural resource agencies with a purpose of understanding the keys to a successful genetics program. An online survey was used to investigate the breadth of molecular marker application to freshwater fisheries management by state natural resource departments. Seven questions were posed to 50 state agencies addressing species of concern, type of genetic resources used, type of molecular marker used, and management concerns. Genetics was listed as a concern in the management of 18 freshwater fish families representing 70 distinct species, with Salmonid species the most frequently reported (20%#37;). A majority of agencies rely on outside resources to perform genetics testing (65%#37;). The most common analysis technique used by state agencies was microsatellite DNA analysis (35%#37;) and the most frequently reported management concerns were genetic stock identification and management boundaries (23%#37;). The application of a specific molecular technology to a conservation question was addressed by investigating the mechanisms of unnatural selection in the form of a study of trait heritability. Microsatellite parentage analysis was used to reconstruct familial relationships of juvenile Florida bass (Micropterus floridanus) displaying variable traits of growth and aggressiveness in a culture setting. Differences in the parentage of high growth and aggression (HGA) and baseline growth and aggression (BGA) offspring showed that certain parent-pairings contribute disproportionally to certain size classes and levels of aggression. These results suggest that the selective pressures of recreational harvest may negatively impact the fitness of wild fish stocks. Overall, this work provides natural resource managers with the basic information required to successfully develop and employ strategies aimed at preserving the genetic integrity of freshwater fisheries.

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