We evaluated endangered Colorado squawfish (Ptychocheilus lucius) as a potential sportfish in Kenney Reservoir from 1988 to 1990 as part of a mitigation program for the construction of Taylor Draw Dam which impounded Kenney Reservoir on the White River, Colorado. A total of 96,597 fingerling squawfish were stocked into Kenney Reservoir from 1988 to 1990. These fish quickly dispersed throughout the reservoir, and downstream into the White River. A small number moved upstream in 1990. A large proportion, associated with high discharge following stocking, exited over the spillway, and continued to move downstream. Catch-per-unit-effort declined drastically in both the river and the reservoir in 1989 and 1990. The rapid disappearance of squawfish throughout the study area was attributed to flow regime, movement patterns, mortality, sampling ineffectiveness or a combination of these. Telemetry observations of six adult Colorado squawfish revealed no difference in behavior attributable to wild or hatchery origin. Stocking squawfish in Kenney Reservoir did not appear to be an effective mitigation procedure for habitat loss due to impoundment. The Colorado squawfish Ptychocheilus lucius is endemic to the Colorado River Basin. Once abundant, its decline has necessitated full protection as an endangered species (Federal Register, Vol. 39[3]:1175, 1974). The historical range of this large cyprinid extended from Northern Sonora, Mexico to Green River, Wyoming, including much of the mainstem Colorado River and most of its larger tributaries (Colorado River Fishes Recovery Team, 1988). It is now restricted to a fraction of its former range, including the main stem Colorado River from Lake Powell to Palisade; the Green River below Brown's Park; the Yampa River below Craig; the White River below Rio Blanco Reservoir; and in portions of the San Juan River in Colorado, Utah and New Mexico (Colorado River Fishes Recovery Team, 1988; Tyus, 1991). Main stem impoundments on the Colorado River system have largely contributed to the decline of Colorado squawfish populations by blocking migration routes and altering flow and temperature regimes (Tyus, 1991). The White River, previously free-flowing, was impounded by Taylor Draw Dam in 1985, 16 river-kilometers east of Rangely, Colorado, creating Kenney Reservoir. The dam effectively reduced the suitable habitat available to squawfish in the White River by 80 km by preventing access to areas upstream from the dam. According to unpublished findings of the Colorado Division of Wildlife, this represents about 16% of the documented range in Colorado. There are no records of Colorado squawfish reproducing in the White River and no suitable spawning conditions have been identified (Carlson et al., 1979; Haynes et al., 1984). In light of this and because of construction mitigation agreements, Colorado Division of Wildlife (CDOW) and the United States Fish and Wildlife Service began a Colorado squawfish stocking program in 1988, calling for 50,000 fingerling-age I Colorado squawfish to be stocked in each of the three years, 1988-1990. After the first stocking in 1988, surHWESTERN RALIST 38(4):362-369 EMBER Trammell et al.-Colorado squawfish veys by CDOW of the reservoir and river indicated the stocked Colorado squawfish had dispersed throughout the reservoir and moved downstream. The study reported here was begun in 1989 to further evaluate dispersal of the 1988 stock and to assess the results of subsequent stockings of Colorado squawfish in Kenney Reservoir. Our primary objectives were to evaluate Colorado squawfish ecology and behavior as they related to attempts to artificially establish these fish in the reservoir as a sport fish, and to evaluate the potential of a sport fishery based on stocked
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Jul 1, 1999
James E Johnson + 1
Open Access