Adult and Juvenile Humpback Chub Monitoring for the Yampa River Population, 2003-2004. Final Report

摘要

The humpback chub (Gila cypha) is an endangered species native to the Colorado River Basin listed under the Endangered Species Act in 1967 (32 FR 4001). The Yampa population of humpback chub includes individuals that may be found in Yampa, Lodore, Whirlpool, and Split Mountain canyons and is one of the smallest existing populations of humpback chub. The objectives of this study are to define the distribution, length frequency and abundance of the adult Yampa humpback chub population and numbers of juveniles in the Yampa humpback chub population. A two-year study began in 2003 that sampled adult humpback chub using trammel nets, boat electrofishing and angling. Juvenile fish were collected using backpack electrofishing and seining. All adult humpback chub were measured for total length (TL), weighed, scanned for the presence of passive integrated transponder (PIT) tags, tagged with PIT tags if none were found and immediately released. All juvenile samples were preserved for laboratory identification.