Razorback Sucker use of the Colorado River inflow of Lake Mead and the lower Grand Canyon

Authors: Ronald B. Kegerries, Brandon Albrecht

Year: 2013 (xlv)

Abstract

Based on past studies and recommendations brought before the Lake Mead Razorback Sucker Workgroup, efforts to locate razorback sucker in the Colorado Inflow Area of Lake Mead (CRI) commenced in 2010 and continued through 2013. Utilizing sonic telemetry, larval sampling, and trammel netting to assess the presence of Razorback Sucker in this area of Lake Mead, 54 adults, one juvenile, and over 80 larval Razorback Suckers were captured; documenting wild reproduction and recruitment at the CRI. With recent movements of sonic-tagged Razorback Suckers into the lower Grand Canyon and the capture of a wild adult near Spencer Creek, questions regarding this population spurred further interest in exploring the lower Grand Canyon for wild Razorback Sucker presence while investigating the relationship between the river and lake as it pertains to Razorback Sucker use. Though Razorback Sucker were thought to be extirpated from the area below Diamond Creek, in the Colorado River, it should be noted that this area has been relatively understudied. Upcoming efforts include the continued monitoring of the CRI with the inclusion of sonic telemetry, larval fish sampling, and small bodied and adult sampling from Lava Falls downstream to Pearce Ferry (RM 180-280). The specific objectives outlined for these efforts include; (1) conduct larval and small-bodied fish studies to quantitatively assess annual fish reproduction, spawning and nursery areas in the Colorado River in the lower Grand Canyon, (2) determine if Razorback Suckers are present in the study area and if they use habitat within the lower Grand Canyon, and (3) determine habitat use, relative spawning and reproductive effort, and population trends of Razorback Sucker in the Colorado River and Lake Mead inflow area.

Resumen

Entra texto de resumen en espaï¿½ol