Date of Award

Spring 2018

Degree Type

Honors College Thesis

Department

Biological Sciences

First Advisor

Brian Kreiser, Ph.D.

Advisor Department

Biological Sciences

Abstract

Alligator gar were historically found across the coastal drainages of the Gulf of Mexico and up into the Mississippi River basin. However, their populations are experiencing decline in many portions of their range. Texas seems to have large populations of alligator gar, but state resource officers are seeking to better understand its biology so as to provide appropriate management recommendations to maintain the recreational fishery. In this study, I used genetic techniques to examine a cohort of 144 juvenile alligator gar collected in 2016 in the Choke Canyon Reservoir. By estimating the effective number of breeders and number of spawning adults, I sought to better understand the reproductive biology of alligator gar and the factors influencing spawning success. I estimated there to be 57 spawning adults with an estimated number of effective breeders of 51. There were no full or half sibling dyads with a probability greater than 0.9. This suggests that the 2016 cohort is the product of spawning by a large group of adults. This agrees with the hydrological conditions from that year, including a lengthy flood period in May, which appeared favorable for an above average level of spawning success. This study is the first of its kind for alligator gar and provides insight into the biology of the alligator gar and enhances our ability to manage this species both in Texas and elsewhere across its range.

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