A Multi-Method Approach for Documenting Wild Razorback Sucker (Xyrauchen texanus) Recruitment in Lake Mead NV, AZ

A variety of methods have been tested and employed to study the unique population of razorback sucker (Xyrauchen texanus) in Lake Mead since 1996.  Recognizing patterns of habitat use and using sonic-tagged individuals to locate wild razorback sucker spawning aggregates have increased sampling efficiency and effectiveness.  More notably these combined methods have helped identify wild recruitment and locate previously unknown spawning populations.  To date, a total of 82 razorback suckers have been equipped with coded sonic transmitters, and with their help more than 800 adult and juvenile razorback suckers have been captured and PIT tagged.  Most importantly, natural recruitment has been identified to occur nearly every year from 1978 to 2008.  Not only do these findings help confirm the overall utility of this suite of methods in locating annual spawning locations, but they also underscore how this multi-method approach has developed our understanding of the overall size and habitat use of the only currently known, wild, and naturally recruiting razorback sucker population.  These methods may be applicable in locating other unknown spawning aggregates, or in establishing a new population of razorback sucker elsewhere in the Colorado River Basin, and is likely applicable across a broad range of species and habitats.