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Full-Text Articles in Life Sciences
Age-Specific Estimates Indicate Potential Deleterious Capture Effects And Low Survival Of Stocked Juvenile Colorado Pikeminnow (Ptychocheilus Lucius), Scott R. Clark, Mary M. Conner, Scott L. Durst, Nathan R. Franssen
Age-Specific Estimates Indicate Potential Deleterious Capture Effects And Low Survival Of Stocked Juvenile Colorado Pikeminnow (Ptychocheilus Lucius), Scott R. Clark, Mary M. Conner, Scott L. Durst, Nathan R. Franssen
Wildland Resources Faculty Publications
Hatcheries and stocking programs have become necessary to repatriate or augment populations of imperiled fishes worldwide. Over nearly two decades, millions of endangered juvenile Colorado Pikeminnow Ptychocheilus lucius have been stocked into the San Juan River (Colorado, New Mexico, and Utah); however, recruitment of these individuals to adult life stages (age ≥6) remains low. Using a mark–recapture data set collected from annual riverwide electrofishing efforts between 2003 and 2016, we investigated apparent survival and capture probabilities of stocked Colorado Pikeminnow to identify age‐specific bottlenecks contributing to this lack of recruitment. With relatively high capture rates, which averaged between 0.34 and …
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
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 …
Growth And Survival Of Colorado Squawfish In The Upper Colorado River, D. B. Osmundson, Ronald J. Ryel, T. E. Mourning
Growth And Survival Of Colorado Squawfish In The Upper Colorado River, D. B. Osmundson, Ronald J. Ryel, T. E. Mourning
Wildland Resources Faculty Publications
Growth and adult survival rates were estimated for the endangered Colorado squawfish Ptychocheilus lucius inhabiting the upper Colorado River by using data from fish captured during 1990–1995. Mean annual growth rates of fish aged 3–6 years ranged from 32.2 (age 6) to 82.0 (age 3) mm/year. Growth rates for older fish were highest for fish 400–449 mm total length, TL, (42.7 mm/year) and declined to 19.8 mm/year for fish 500–549 mm TL. Fish 550 mm and longer grew an average 9.5 mm/year. Survival rates for fish 550 mm and longer were estimated by comparing measured size distributions with simulated stable …