The Effects of Electrofishing on the Reproductive and Developmental Health of Razorback Sucker in the Colorado River Basin
Razorback sucker is a federally endangered fish species endemic to the Colorado River Basin. Reclamation funds and manages three major programs concerned with the management of razorback suckers. These management activities include re-establishing a razorback sucker population with hatchery-reared fish and removal of non-native fish species that pose a predation and competition threat to the species. The programs also monitor survival and reproduction of stocked individuals to evaluate their response to management activities. Subadult and adult razorback suckers are exposed to electrofishing from April through October during non-native removal and monitoring.
Because of intensive non-native removal efforts and monitoring, native fish, including razorback sucker, may be exposed to up to 13 electrofishing passes in a single year. Limited studies have documented the negative impacts of electrofishing in ripe adult and embryo razorback suckers (Muth and Ruppert 1996; Muth and Ruppert 1997); however, no studies have looked at the impacts or effects of repeated exposure to electrofishing throughout the year on the reproductive health of adult razorback suckers.
This study will investigate the effects of continuous and periodic electrical exposures on the reproductive and developmental health of the endangered razorback sucker (_Xyrauchen texanus_). Our study addresses the specific question of what are the indirect effects of repeated electrofishing from non-native fish suppression on survival, gametogensis, and growth and development in adult and larval razorback suckers.
There are three main objectives proposed:
1. Determine the effects of electrofishing on gametogenesis and fish health in razorback sucker broodstock.
2. Determine the effects of electro-hocking on razorback sucker fertilization, embryogenesis, and larval survival and development.
3. Determine the critical period of susceptibility for adult razorback sucker fitness to electroshocking.
Need and Benefit
The problem directly relates to the ability of Reclamation to simultaneously pursue two primary recovery management actions for the endangered razorback sucker in the Colorado River Basin: (1) the re-establishment of a self-reproducing population of razorback sucker through stocking and (2) aggressively pursuing the elimination or reduction of non-native fish using electrofishing. Ultimately, this project relates to the recovery of endangered species in the Colorado River Basin and the ability of several Federal agencies to meet that goal. It directly relates to Reclamation's mission of delivering water and power while meeting our responsibilities and commitments.under the Endangered Species Act.
Fish and Wildlife Service, Department of the Interior
U.S. Geological Survey, Department of the Interior
Upper Colorado Regional Office, Upper Colorado Region