Meeting Abstract
Hybridization is a natural process, however, human activities have contributed to an increase of hybrid species. In North America alone, 40% of fish species of conservation concern have been impacted by hybridization and introgression. Of eminent concern is the hybridization of native species with introduced or invasive species. Samples collected from the Brazos River from 2006 and 2012 display intermediate phenotypes between the invasive Cyprinodon variegatus and the native Cyprinodon rubrofluviatilis, suggesting that hybridization has occurred between these species. The extent of hybridization and introgression between two species can not be determined by morphological characters as cryptic hybrids, individuals that phenotypically look like one species yet possess alleles unique to the second species, may be present. Genetic analysis using microsatellite markers of five parental populations and four hybrid populations provides the resolution needed to identify hybrid individuals and determine the impact of C. variegatus in the Brazos River. Preliminary data show that alleles unique to C. variegatus are present in both putative hybrids collected from the Brazos River in 2013 and samples collected from Salt Fork of the Brazos River in 2014 and 2015 upstream from Possum Kingdom Reservoir. However, samples collected from the Wichita River and the Red River do not possess these unique C. variegatus alleles. This suggests that C. variegatus and cryptic hybrids may have been present further upstream than originally documented. Additional sampling and genetic analysis is needed to understand the full impact C. variegatus has had on populations of C. rubrofluviatilis and if conservation efforts are needed to protect the loss of C. rubrofluviatilis genetic integrity.
