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Rainbow trout growth data and growth covariate data downstream of Glen Canyon Dam in the Colorado River, Arizona, 2012 - 2016

July 21, 2020

These data are the primary data used to estimate rainbow trout abundance and survival in the Colorado River, Glen and Grand Canyons. Refer to the analyses as per the associated journal manuscript (see Larger Work Citation). Prey availability, feeding efficiency, and competition reduce somatic growth and cause the collapse of a fish population" Nighttime boat electrofishing was used to sample rainbow trout four times per year in April, July, September, and January, from April 2012 through September 2016. A total of five reaches were sampled between Glen Canyon Dam (river kilometer [rkm] 0) to below the confluence with the Little Colorado River (located at rkm 130). Reaches ranged from two to six km in length. A total of 47,056 individual rainbow trout were tagged with passive integrated transponders (PIT) over the first 18 trips across the five study reaches. and 7,733 of these individuals were recaptured one or more trips after they were released. A total of 1,477 individuals (19%) were recaptured more than once (i.e., on two or more trips after release). In total, 9,542 across-trip recaptures with length and weight measurements on release and recapture events were obtained. Very few tagged fish were recaptured in reaches other than the ones they were released in, and these fish were excluded from the analysis. Provided are tabulated data for fish capture (158,324 records), size-stratified abundance estimates by reach and sampling trip, and the upper and lower confidence intervals for total abundance. We evaluated the effects of discharge, water temperature, solar insolation, turbidity-driven reactive distance (feeding efficiency), intraspecific competition, and prey availability on growth rates of rainbow trout. These six covariates were selected based on hypotheses of how they affect the rate of prey delivery, metabolic and foraging costs, foraging efficiency, and prey availability. Covariates are compiled as tabulated mean values for each reach and sampling trip and corresponding data sources.

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