Detecting Razorback Suckers Using Passive Integrated Transponder Tag Antennas in the Green River, Utah

In order to increase detections of razorback suckers Xyrauchen texanus tagged with passive integrated transponders in the upper Colorado River basin, we deployed two passive instream flat-plate antennas (33 × 68 cm) at a razorback sucker spawning location in the Green River, Utah, during spring of 2012 and 2013. Over the course of 29 d in 2012 and 90 d in 2013, the antennas detected 569 razorback suckers, 19 Colorado pikeminnow Ptychocheilus lucius, 16 flannelmouth suckers Catostomus latipinnis, and 1 bluehead sucker Catostomus discobolus. Despite extensive sampling via boat electrofishing (rafts and hard-bottom boats) and netting (fyke, trammel, and gill) in wetlands that occurred from the 1990s to present in the upper Colorado River basin, a large number of tagged razorback suckers and Colorado pikeminnow, including a fish released in 1996, were detected for the first time by our antennas. Our data indicate that the detectability of razorback suckers, and precision and accuracy of survival and population estimates might be increased significantly with the addition of data gathered by passive instream flat-plate antennas in the Green River.