Sibship Reconstruction for Inferring the Number of Breeders of Gulf Sturgeon in the Apalachicola River
Date of Award
Honors College Thesis
The Gulf sturgeon is an anadromous fish that inhabits the Gulf of Mexico and its neighboring river drainages. The species is currently listed as threatened due to habitat alterations and overfishing. In this study, we focused on the Apalachicola River in Florida, which has had several historic spawning locations of the sturgeon blocked by the Jim Woodruff Lock and Dam. Age-1 juvenile sturgeon from the year 2013 (n=31) and 2014 (n=131) were genotyped using fourteen microsatellite loci. Sibship reconstruction and parentage assignment was performed in order to determine the effective number of breeders (Nb) and the total number of spawning adults (NS). Genetic diversity measures in the two cohorts proved to be very similar. The 2013 sample had an Nb value of 38 and an NS value of 28 while the 2014 sample had an Nb of 84 and an NS of 79. Although there was a difference in the reproductive success between years, there wasn’t much skew in terms of reproductive success of the parents contributing to a given cohort. It is not entirely clear why the 2014 age-1 cohort was larger, but it could reflect favorable environmental conditions increasing the number of spawning adults or increasing the survivorship of juveniles spawned that year. Overall, the genetic approach of inferring the number of breeders from sibship reconstruction proved to be an effective measure of reproduction in Gulf sturgeon and should be used in other river systems in future studies.
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Verges, Robbilyn, "Sibship Reconstruction for Inferring the Number of Breeders of Gulf Sturgeon in the Apalachicola River" (2018). Honors Theses. 593.