Native Fish Dominance in the Grand Canyon, Arizona

Authors: Ronald Rogers, Brandon Albrecht, Ronald Kegerries, Harrison Mohn, Mark McKinstry, Brian Healy, Robert Schelly

Year: 2018

Abstract

In 2012, BIO-WEST, Inc. (BIO-WEST) researchers observed sonic-tagged Razorback Suckers moving from the Colorado River inflow area of Lake Mead upstream into the lower Grand Canyon. As tracking efforts attempted to define movement patterns and habitat use, it became apparent that these fish were using the Colorado River in the lower Grand Canyon. Small-bodied sampling began in the Grand Canyon in 2014 from river mile (RM) 179.1 (Lava Falls Rapid) to RM 280.0 (Pearce Ferry) and continued through 2015 until researchers learned that Razorback Sucker spawning was occurring upstream of this area. Since 2016, small-bodied fish community sampling in the Grand Canyon has been conducted from RM 88.5 (Phantom Ranch) to RM 280.0. These efforts have resulted in the capture of four native (Bluehead Sucker Catostomus discobolus, Flannelmouth Sucker Catostomus latipinnis, Humpback Chub Gila cypha, and Speckled Dace Rhinichthys osculus) and eight nonnative fish species, as well as documentation of young-of-the-year (age-0) catostomids and cyprinids. These results show that approximately 90% of the Grand Canyon fish community is comprised of native species and demonstrates the need for continued research throughout the Grand Canyon to determine mechanisms allowing for native fish domination.