PARENT SESSION
Oral Session #85: Ecosystem Restoration in the Grand Canyon.
Presiding: S. Gloss and B. Gold
Thursday, August 8. 1:00 PM to 3:45 PM. Mohave Meeting Room, TCC.

Balancing conservation of native fishes and a recreational trout fishery: is it possible under an Adaptive Management Program?

Persons, William^*,1, Speas, David¹, McKinney, Ted¹, Riley, Lawrence¹, ¹ Arizona Game and Fish Department, Phoenix, AZ

ABSTRACT- Closure of Glen Canyon Dam on the Colorado River in 1963 led to establishment of a 26-km tailwater rainbow trout (Oncorhynchus mykiss) fishery. Stabilized releases from Glen Canyon Dam as a result of the Glen Canyon Dam Environmental Impact Statement and Record of Decision in 1996, designed to benefit native fishes and other resources including trout, has led to increased natural recruitment of trout in both the tailwater and downstream reaches. The recreational fishery has flourished, and has long supported a local economy comprised of fishing guides, motels and restaurants, and a large and vocal user group. At the same time, the population of endangered humpback chub (Gila cypha) found 98 km downstream, has declined. Causes for the decline are poorly understood, and likely include many factors, including unfavorable water temperatures, exotic parasites, and interactions with non-native fishes. Increases in rainbow trout and brown trout (Salmo trutta) densities in downstream reaches has heightened concerns for the future of humpback chub, and led to proposed experiments within the Adaptive Management Program to disadvantage these non-native predators to benefit native fishes. The increased tension between management efforts for a recreational fishery and native fish conservation pose severe challenges to the members of the Adaptive Management Program.

KEY WORDS: Oncorhynchus mykiss, Gila cypha , adaptive management