Status of Bluehead Sucker populations in the Weber, Snake, and Bear rivers, northern Utah

Authors: Phil K. Tuttle, Paul D. Thompson

Year: 2013 (xlv)

Abstract

Bluehead sucker (Catostomus discobolus) are known to occur throughout the Colorado, Snake, and Bonneville Basins, but until recently, little information on this species was known outside of the Colorado River Basin. Recent MtDNA results identified three bluehead sucker evolutionary significant units, which indicate that populations in the Colorado and Bonneville/Snake Basins are distinct and could even be considered different species. This recent finding has further prompted state wildlife agencies to better determine the population distribution and status of bluehead suckers in the Bonneville and Snake River Basins. In Utah, the Utah Division of Wildlife Resources (UDWR) began surveying in 2003 for bluehead suckers in the Snake, Bear, and Weber rivers. Bluehead sucker populations remain in many sections of the Weber River, a robust population has been discovered in the Raft River, but no populations have been found in the Utah portion of the Bear River. The UDWR began monitoring populations in the Weber River in 2007 with mark/recapture electrofishing and through the use of Passive Integrated Tags; these populations are small and reproduction/recruitment is limited. The Weber River is a highly fragmented stream, but mark/recapture information indicates that bluehead suckers are moving long distances of up to 15.0 km. In an effort to reconnect habitat, the UDWR and partners constructed a fish passage channel in 2011 at a major mainstem diversion in the Weber River. Monitoring of the passage channel in 2012-2013 has indicated that six juvenile bluehead suckers have moved upstream past this structure. Considering the genetic background and potential lack of recruitment and/or reproduction, we feel the Weber River populations are imperiled and warrant additional research and management focus.