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<br />002781 <br /> <br />accumulate. Furthermore, a high diversity among the natural populations indicated surviving <br />individuals were produced by a large number of females, likely more than exist in the region today. <br />This high diversity and lack of appreciable differentiation of existing populations is consistent with <br />considerable interconnection of regions. The results indicated that there are no genetic differences <br />among razorback stocks in the Upper Colorado River Basin. However, there is more genetic <br />diversity among Lower Basin states. The study also concluded that concerns over hybridization <br />should focus on other species, as introduced (non-native) species (e.g., white suckers, tlannelmouth <br />suckers) are most likely to have the greatest impact on Jill native Colorado River species. <br /> <br />4.3 Genetic Survey of Colorado squawfish <br /> <br />The Propagation/Genetics Management Plan document included a section pertaining to genetics <br />information that is needed regarding the various Colorado squawtish populations. In addressing these <br />needs, a genetic survey of Colorado squawtish was initiated in 1991. The goal of this survey was to <br />determine the genetic status of Colorado squawfish in order to more effectively protect and manage <br />the species for sustained recovery (U.S. Fish and Wildlife Service 199Ib). <br /> <br />Based on the literature and conversations with knowledgeable biologists, nine sites were identified <br />for sampling adult Colorado squawfish and seven sites for sampling Y oung-Of- Year (YaY). These <br />included sites on the Yampa, Green, Colorado, and San Juan rivers and the Dexter National Fish <br />Hatchery. Sampling teams were identified early on for the Yampa, Upper Green, and San Juan <br />Rivers. They were equipped to sample fin, muscle, and gametes. Only the Yampa and Upper Green <br />teams were trained and equipped to sample blood. <br /> <br />Muscle, fin, and blood samples were obtained from 30 adult Colorado squawfish in both the Yampa <br />and Upper Green Rivers. Gametes, milt in all cases, was obtained from about two thirds of those <br />fish; ripe females were not captured so eggs were not obtained. Most of the adult fish required to <br />meet the sample requirements from the Upper Colorado River had been obtained in 1991 by Colorado <br />River Fisheries Project staffin Grand Junction with an additional dozen fish captured in 1992. Less <br />than 10 adults were sampled in the San Juan River All adults from which tissue samples were taken <br />were PIT -tagged and released. Tissue samples were sent for genetic analyses. <br /> <br />Allozyme analyses were perrormed on fin and muscle tissues from adults and whole yay specimens <br />starting in 1992. Most geneticists recommend multiple analytical methods be applied to generate <br />independent data sets to serve as validation tools. Mitochondrial DNA analysis was one of the <br />chosen methods. However, RAPD (random amplified polymorphic DNA analyses) seemed to offer <br />greater informational opportunities and was selected as the alternate method. The blood samples <br />taken from the Yampa and Upper Green River specimens were used for the RAPD analyses. <br /> <br />The allozyme analyses of the preliminary genetic studies designed to help characterize wild and <br />captive populations of Colorado squawtish were completed in 1993. Only final reporting of the data <br />remained, followed by interpretation of the results and management recommendations by contractors <br />and the Genetics Panel. RAPD analyses continued into 1994 (U.S. Fish and Wildlife Service 1993). <br />However, the company that was perrorming the RAPD analyses ceased operations in 1995 resulting <br />in a large amount of uncertainty as to the completion of the genetic survey. Another contractor was <br /> <br />21 <br />