Roundtail Chub Gila robusta, and the White River: A look at propagation in a natural oxbow.

Authors: Michael D.* Fiorelli, Matthew J. Breen

Year: 2015 (xlvii)

Abstract

The White River in Utah is critical habitat for Bluehead sucker, Catostomus discobolus, flannelmouth sucker ,Catostomus latipinnis, and roundtail chub, Gila robusta. These species have suffered reductions of their historic range in the upper Colorado River basin, and are listed as a Tier I Sensitive Species in Utah. Recent investigations in the White River have revealed strong populations of both bluehead and flannelmouth sucker with population estimates of 598 flannelmouth/mile (CI = 450 -746), and 282.52 bluehead/mile (CI = 221-392). However roundtail estimates have not been possible due to low recapture rates. In response to low recapture rates from electrofishing surveys, we initiated a netting protocol specifically targeting roundtail which also yielded low capture rates. It was determined that roundtail populations should potentially be bolstered in the White River as a result of low capture rates and limited evidence of recruitment during 2012 Á¢â‚¬ ’ 2014 fall seining surveys. In the spring of 2015 an off channel oxbow was formed on the White River presenting an excellent opportunity for roundtail propagation. This oxbow is 0.64 km long, with widths varying from 23 to 50 meters. Initial investigation of the oxbow in August found two disconnected pools. The downstream poolÁ¢â‚¬â„¢s maximum depth was 48 cm and was determined to be unfit for propagation. However, the upstream pool may provide the necessary requirements for roundtail propagation. This pool has an area of 0.18 acres with a maximum depth of 147 cm. A majority of measured depths in this pool were over 100 cm. The substrate is primarily silt/mud with very limited amounts of rock of any size class. This winter and fall we will deploy dissolved oxygen meters, and check on ice depths to determine if over winter survival is feasible. We will also deploy trail cameras in the spring to follow how the pool changes with spring runoff. It is our hope to use the data gathered between this fall and next spring to determine what modifications, if any, will be necessary to create suitable conditions for roundtail propagation in the White River.