Laserfiche WebLink
EXECUTIVE SUMMARY <br />Numerous factors contribute to the decline of indigenous fishes in western North <br />America. While habitat alteration is a major concern for indigenous fish communities, <br />impromptu introduction of alien species is probably a more serious threat to their long- <br />term survival. Impacts of the latter are less immediate, and often go unnoticed by the <br />general public. Introgression of alien genes gradually erodes the genetic in#egrity of <br />native species, and irreversibly alters the local genetic adaptation that has evolved over <br />million of years. As a result, indigenous genes become replaced and the endemic fauna <br />is effectively eliminated. <br />This study focuses upon introgressive hybridization between introduced White <br />Sucker (Catostomus commersoni) and endemic suckers of the Colorado River Basin <br />[i.e., Flannelmouth Sucker (C. latipinnis); Bluehead Sucker (C. {Pantosteus} <br />discobolus)]. These three now hybridize in a 50-mile reach of the Yampa River in <br />Colorado between Craig and Lily Park. The goal of this project is to determine the <br />extent and magnitude of this event through the utilization of molecular genetic <br />approaches. <br />This study addresses four objectives: <br />(1) Derivation of primers that amplify specific non-coding regions of the <br />nuclear genome (called introns) within the three target species. <br />(2) Application of these primers (in conjunction with EPIGPCR and SNP <br />analysis) to screen individuals sampled non-lethally in the 50-Mile reach. <br />(3) Determination of pure, hybrid, and backcrossed individuals at each of <br />several sample localities in the reach. <br />(4) Comparison of genetic results with field-based morphological <br />identification, so as to assess abilities of researchers to phenotypically determine <br />levels of hybridity. <br />(5) Interpretation of genetic data with regard to management of the <br />introduced White Sucker. <br />2 <br />