Humpback chub translocation to Havasu Creek, Grand Canyon National Park: Implementation and monitoring plan

Trammell, Melissa; Healy, Brian; Omana Smith, Emily; Sponholtz, Pamela

Humpback chub is an endangered species endemic to the Colorado River. Translocation of humpback chub into Grand Canyon tributaries has been identified as a tool for mitigating impacts of dam operations and providing population redundancy in the lower Colorado River basin. Havasu Creek is one of the larger tributaries to the Colorado River in Grand Canyon National Park, and the one most similar to the Little Colorado River in hydrology, habitat, and water chemistry. It is one of several tributaries evaluated by Valdez et al. (2000) for the potential to establish a second humpback chub (Gila cypha) population in Grand Canyon, to provide population redundancy in the case of catastrophic failure of the Little Colorado River aggregation. Havasu Creek’s potential to support a second spawning aggregation of humpback chub was ranked highest of the tributaries evaluated (Valdez et al. 2000). Translocations of humpback chub were the recommended method for attempting to establish a second population of humpback chub in the Grand Canyon. This monitoring plan establishes a release schedule and monitoring methods to be used for the first three years of this study. Monitoring methods will be evaluated annually and refined as needed. Additional experimentation with passive integrated transponder (PIT) tag scanning techniques will be explored to improve remote sensing capabilities and maximize ‘captures’ of tagged fish. Carrying capacity estimations will be refined and translocation release numbers may be adjusted accordingly. Havasu Creek will be evaluated to determine the best use of this tributary as a translocation site. Potential outcomes include use as a grow-out area, augmentation of the local aggregation, a refuge, and ideally, a second spawning population in Havasu Creek. Criteria for success for this translocation effort will be established and evaluated in the final report. Criteria may include (a) retention of translocated humpback chub for a minimum of one year, (b) similar or increased survival of juveniles relative to mainstem, (c) similar or increased growth rates relative to the Little Colorado River and mainstem, (d) contributions to the mainstem aggregation, (e) evidence of successful reproduction, (f) measureable numbers of young, and (g) evidence of recruitment.

Humpback chub translocation to Havasu Creek, Grand Canyon National Park: Implementation and monitoring plan

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