A small number of fish released into the Colorado River within Grand Canyon National Park hopefully will turn into tattletales.
Fisheries biologists in the park hope the nine adult endangered razorback suckers (Xyrauchen texanus) released downstream of Lava Falls (River Mile 180) will lead them to other suckers.
A native fish found only in the Colorado River basin, the razorback sucker was previously believed to have been extirpated from Grand Canyon National Park. But it was rediscovered in October 2012 during surveys by the Arizona Game and Fish Department. By tracking the sonic-tagged fish that were released, biologists may be able to detect groups of other spawning razorback suckers, and assess their movements and habitat use.
While the monitoring of razorback sucker has been conducted in Lake Mead National Recreation Area for several years, this is the first time a study such as this has been conducted in Grand Canyon National Park. Fisheries biologists will attempt to track the fish during monthly river trips occurring between April and September, by using specialized equipment designed to detect signals emitted from the tagged fish.
Studies conducted during the past three years at the Colorado River inflow area in Lake Mead National Recreation Area suggested that wild razorback suckers are migrating into the Colorado River in lower Grand Canyon. Several fish were tracked upstream as far as Separation Rapid (River Mile 240), and wild un-tagged fish were captured in lower Grand Canyon as part of annual monitoring in 2012 and 2013. These were the first detections of the species in Grand Canyon National Park since the 1990s.
The razorback sucker study is a component of the recently released Comprehensive Fisheries Management Plan for Grand Canyon National Park.