Ichthyofaunal survey of the Dirty Devil River, 2012

Authors: Jennifer L. Hester, Michael A. Farrington, Steven P. Platania, W. Howard Brandenburg

Year: 2013 (xlv)

Abstract

To avoid further decline of imperiled native fish species in the American Southwest, proactive management plans such as the Range-Wide Conservation Agreement for Roundtail chub, Gila robusta, Bluehead sucker, Catostomus discobolus, and Flannelmouth sucker, Catostomus latipinnis have recently been enacted. These species are collectively referred to as the ‘three species’. The Dirty Devil River, a tributary of the Colorado River in southeastern Utah, historically contained each of the three species. Between 29 February and 6 March 2012, we conducted an ichthyofaunal survey of the Dirty Devil River between Hanksville and Lake Powell, Utah (129 km). Our goal was to conduct a baseline survey of the fish community in order to assess the conservation status of the three species within the Dirty Devil River. The sampling units on the Dirty Devil River were selected using the Generalized Random Tessellation Stratified (GRTS) sampling design. The program ‘S-Draw’ (Western EcoSystems Technology, Inc. - Trent L. McDonald) was used to generate a list of 33 randomly selected sampling units within the study area. A total of 17,471 m² of instream habitat was sampled among the 33 sampling units. A total of 76 specimens were collected representing five species and three families. Flannelmouth sucker was the only native species collected; nine individuals were collected at six sampling units. The results of this survey suggest a depauperate ichthyofaunal community within the Dirty Devil River. This is likely caused by extensive dewatering of the Dirty Devil River through numerous surface water diversions found along its two major tributaries (the Muddy and Fremont Rivers).