Date of Award

Fall 12-2013

Degree Type

Masters Thesis

Degree Name

Master of Science (MS)

Department

Biological Sciences

Committee Chair

Brian Kreiser

Committee Chair Department

Biological Sciences

Committee Member 2

Jake Schaefer

Committee Member 2 Department

Biological Sciences

Committee Member 3

Greg Moyer

Abstract

The alligator gar (Atractosteus spatula) is a large-bodied species of fish that historically was widely distributed in coastal drainages around the Gulf of Mexico and well north in the Mississippi River basin. Currently this species is experiencing population declines across much of its range. However, in some parts of its range, such as Texas, this species has shifted from being viewed as a trash fish to being the target or a growing sport fishery. As populations decline and angling pressure increases, different state agencies are faced with the common challenge of developing the most effective methods for managing this species. A general lack of basic life history information makes this task a challenge. Here, the population structure of A. spatula was examined on both a fine-scale (within 10 km) and large scale (across its entire range). With an understanding of the stock structure of this species, management efforts can be tailored to best preserve the remaining genetic diversity of this species. In addition, possible hybridization between A. spatula with Lepisosteus osseus (longnose gar) and L. oculatus (spotted gar) was investigated by genotyping morphologically suspect individuals. Finally, microsatellite loci originally identified in A. spatula were cross-amplified in A. tropicus (tropical gar) to identify a set of microsatellite markers for the genotyping of A. tropicus, another species of gar that has generated interest in managing and restocking its remaining populations.

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