Submersible PIT Antennas Document a New Spawning Location for Colorado Pikeminnow, Ptychocheilus lucius, in the Green River, Utah

Authors: Michael Partlow, Matthew Breen, Garrett Tournear

Year: 2018

Abstract

Colorado Pikeminnow, Ptychocheilus lucius, is a long-lived, potamodromous fish that exhibit spawning site fidelity. Following decades of research in the Green River sub-basin, two primary spawning sites have been identified, one in Yampa Canyon(Yampa River) and the other in Gray Canyon (Green River). In July 2018, a suspected spawning aggregation of Colorado Pikeminnow was encountered during non-native fish removal electrofishing in Dinosaur National Monument near the Chew Bridge (river km 508) downstream of Split Mountain Canyon. In response, a remote submersible PIT antenna (Biomark, Inc., Boise, ID) was promptly deployed at this location from 10–30 July 2018. During this time, 50 unique PIT tags were detected, 42 of which were implanted into Colorado Pikeminnow; three were implanted into Razorback Suckers, Xyrauchen texanus, and five remaining tags have not yet been reconciled with an existing record of implantation. Remote submersible PIT antennas may be a valuable tool for investigating life history traits of endangered fishes in place of more intrusive sampling techniques, such as netting and electrofishing, that potentially disrupt spawning behaviors. Future monitoring of this site with submersible PIT antennas should continue in subsequent years and additional research should be conducted to determine when passive detection of PIT tags can be positively attributed to spawning activity.