The population of endangered razorback suckers Xyrauchen texanus in the middle Green River (upper Colorado River basin) has declined during the last 40 years. The apparent cause for this decline is a lack of successful recruitment. This study used radiotelemetry to evaluate the ability of hatchery-reared razorback suckers to locate spawning areas where wild fish congregate during the ascending hydrographic limb of the snowmelt runoff. Hatchery-reared razorback suckers appeared to show similar reproductive behavior to wild fish. Both wild and hatchery-reared fish were found near the middle Green River spawning area between 1 and 25 May 2000. Hatchery fish occupied the same areas on the spawning site as wild fish, and remained on the [...]
