Using telemetry as a tool to locate razorback sucker (Xyrauchen texanus) spawning aggregates and identify wild recruitment in Lake Mead NV, AZ

Authors: Ronald B. Kegerries

Year: 2011 (xliii)

Abstract

Sonic telemetry was first implemented in the Lake Mead razorback sucker (Xyrauchen texanus) studies during the 1996-1997 study year. During the past 15 years a total of 82 razorback sucker have been equipped with coded sonic transmitters. It was thought that telemetry would provide valuable biological data regarding movement, habitat use, and spawning locales throughout Lake Mead, much as it has throughout the Colorado River Basin with other native fishes. Recognizing patterns of habitat use and using these individuals to locate wild razorback sucker spawning aggregates have increased sampling efficiency and effectiveness and has helped to identify wild recruitment of this unique population in Lake Mead. Additionally, the use of sonic telemetry in the Lake Mead razorback sucker studies resulted in the discovery of two previously unknown spawning aggregates. Not only do these findings help confirm the overall utility of this method in locating spawning locations, but also underscore how telemetry techniques have helped in better understanding the overall size and habitat use of wild Lake Mead razorback sucker populations. Sonic telemetry has been a valuable tool in tracking spawning aggregate shifts in this highly dynamic reservoir as water levels have fluctuated over time. Although sonic telemetry technology has been used for many years as a method to study various fish species, it has proved to be a valuable tool in the Lake Mead razorback sucker studies when combined with other methods to evaluate wild recruitment. Furthermore, these methods may be applicable in locating other unknown spawning aggregates, or establishing a new population of razorback sucker elsewhere in the Colorado River Basin.