Digital Commons Network^™

Dispersal Patterns Of Subadult And Adult Colorado Squawfish In The Upper Colorado River, D. B. Osmundson, Ronald J. Ryel, M. E. Tucker, D. B. Burdick, W. R. Elmblad, T. E. Chart

Wildland Resources Faculty Publications

Abstract.—We investigated distribution and dispersal patterns of subadult and adult Colorado squawfish Ptychocheilus lucius (recently renamed the Colorado pikeminnow) throughout their range in the upper Colorado River. Annual, river-wide, capture–recapture data were used to document movements during a 5-year period (1991–1995). Average total length of Colorado squawfish progressively increased upstream: juveniles and subadults occurred almost exclusively in the lowermost 105 km of the 298-km study area, whereas most adults were concentrated in the uppermost 98 km. This was most pronounced early in the study and less so later due to the effect of two or three strong year-classes that dispersed …