Survival, Condition, Habitat Use, and Predation on Stocked Bonytails (Gila elegans) in the Green River, Colorado and Utah

Bestgen, Kevin R.; Zelasko, Koreen A.; Compton, Robert I.; Chart, Tom E.

doi:10.1894/gg-29.1

Cited by 14 publications

(21 citation statements)

References 15 publications

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“…Fish & Wildlife Service). Historically, Colorado Pikeminnow co‐occurred with Bonytail throughout the Colorado Basin (Gobalet, Wake, & Hardin, ; Minckley et al, ; Quartarone, ) and preyed on Bonytail in their natural environment (Bestgen et al, ). The availability of on‐site, disease‐free fish and the co‐evolved predator‐prey interaction made Colorado Pikeminnow a logical biological control candidate for our study.…”

Section: Methodsmentioning

confidence: 99%

“…Stocking efforts for Bonytail have met with limited success. Recapture rates and long‐term survival of hatchery‐released fish are low (Bestgen, Zelasko, Compton, & Chart, ; Pacey & Marsh, ). Previous research suggests reintroduction efforts of fish less than 225 mm total length (TL) were most likely lost to predation by nonnatives (Bestgen et al, ).…”

Section: Introductionmentioning

confidence: 99%

“…Recapture rates and long‐term survival of hatchery‐released fish are low (Bestgen, Zelasko, Compton, & Chart, ; Pacey & Marsh, ). Previous research suggests reintroduction efforts of fish less than 225 mm total length (TL) were most likely lost to predation by nonnatives (Bestgen et al, ). Additional research shows post‐stocking survival of other hatchery‐reared Colorado River fishes strongly correlates with size at release, with larger individuals having greater survival (Marsh et al, 2004; Pacey & Marsh, ; Bestgen, Zelasko, & White, ; Zelasko et al, 2010).…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Endangered species managing endangered species: Polyculture of piscivorous Colorado Pikeminnow (Ptychocheilus lucius) with production Bonytail (Gila elegans) to control recruitment and increase growth rates

et al. 2019

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The decline and endangerment of native fish has led to an increase in hatcheries that sustain and augment threatened and endangered species. In an effort to restore self‐sustaining populations, hatchery‐reared Bonytail (Gila elegans) are released into the lower Colorado River annually. Current augmentation protocols for Bonytail require a minimum stocking size of 300 mm total length due to greater apparent survival of larger individuals. The fish culture process of reaching this desired target size requires multiple years of growth, during which precocious individuals regularly spawn. Recruitment in production ponds increases densities, potentially reducing growth rates and adversely affecting culture conditions. Polyculture techniques have been shown to have synergistic effects and under proper conditions effectively control unwanted biota. In an effort to address the management implications of Bonytail recruitment on adult growth and survival, we tested the use of a historically co‐occurring piscivore, Colorado Pikeminnow (Ptychocheilus lucius), as a biological control agent. Colorado Pikeminnow effectively controlled Bonytail recruitment and had a positive effect on adult growth rates. Our results suggest polyculture of these two species can aid management actions by increasing augmentation efforts.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Endangered species managing endangered species: Polyculture of piscivorous Colorado Pikeminnow (Ptychocheilus lucius) with production Bonytail (Gila elegans) to control recruitment and increase growth rates

et al. 2019

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“…Stocking efforts for Bonytail have experienced limited success, likely due to low survival rates of stocked fish (Bestgen et al. ; Pacey and Marsh ). Previous research suggests that body size is a major factor in determining postrelease survival.…”

Section: Size‐based Management Of Bonytailmentioning

confidence: 99%

Size Sorting in Bonytail Skews the Sex Ratio of Stocked Fish

Diver

Harrison

Knight

et al. 2019

N American J Fish Manag

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For sexually dimorphic species, size‐based management can cause changes in the sex ratio of the target population. Bonytail Gila elegans populations in the Colorado River basin are augmented annually in an effort to re‐establish wild populations. To increase survival rates of stocked individuals, the Lower Colorado River Multi‐Species Conservation Program's Habitat Conservation Plan implemented a minimum stocking size. Anecdotal reports on hatchery populations suggest that females grow at a faster rate and reach larger sizes than males. If this observation is correct, a minimum stocking size may cause skewed sex ratios of stocked populations. To test this prediction, we compared average male and female lengths in 3‐year‐old fish from two cohorts before and after they were sorted by size. Our data support the observation that size in Bonytail is sexually dimorphic by age 3, with females being the larger sex. This is also the age at which fish begin to reach the minimum size to meet stocking requirements. As predicted, size‐grading produced a significantly skewed sex ratio in the animals slated for release. The consequences of augmenting wild populations with groups of animals having skewed sex ratios are largely unknown but could include increased mate competition, inadvertent artificial selection, or a reduction in genetic diversity.

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“…In an attempt to save endangered populations, managers, conservationists, and scientists have developed strategies of supportive breeding, which can include artificial crosses in captivity, as well as release of offspring into the wild. However, these well‐intentioned initiatives can promote maladaptive traits as natural selection and can be distorted by human intervention (e.g., Bestgena, Zelaskoa, Comptona, & Chartb, ; Jónás et al., ; Levin, Zabel, & Williams, ; Massaro et al., ). Reducing the number of captivity generations is expected to reduce the extent of adaptation to captivity (Frankham, ) and potentially increase the success of reintroduction of populations into the wild from captivity.…”

Section: Introductionmentioning

confidence: 99%

Nature versus nurture? Consequences of short captivity in early stages

Hórreo

Valiente

Ardura

et al. 2017

Ecology and Evolution

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Biological changes occurring as a consequence of domestication and/or captivity are not still deeply known. In Atlantic salmon (Salmo salar), endangered (Southern Europe) populations are enhanced by supportive breeding, which involves only 6 months of captive rearing following artificial spawning of wild‐collected adults. In this work, we assess whether several fitness‐correlated life‐history traits (migratory behavior, straying rate, age at maturity, and growth) are affected by early exposure to the captive environment within a generation, before reproduction thus before genetic selection. Results showed significant differences in growth and migratory behavior (including straying), associated with this very short period of captivity in natural fish populations, changing even genetic variability (decreased in hatchery‐reared adults) and the native population structure within and between rivers of the species. These changes appeared within a single generation, suggesting very short time of captivity is enough for initiating changes normally attributed to domestication. These results may have potential implications for the long‐term population stability/viability of species subjected to restoration and enhancement processes and could be also considered for the management of zoo populations.

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Survival, Condition, Habitat Use, and Predation on Stocked Bonytails (Gila elegans) in the Green River, Colorado and Utah

Cited by 14 publications

References 15 publications

Endangered species managing endangered species: Polyculture of piscivorous Colorado Pikeminnow (Ptychocheilus lucius) with production Bonytail (Gila elegans) to control recruitment and increase growth rates

Endangered species managing endangered species: Polyculture of piscivorous Colorado Pikeminnow (Ptychocheilus lucius) with production Bonytail (Gila elegans) to control recruitment and increase growth rates

Size Sorting in Bonytail Skews the Sex Ratio of Stocked Fish

Nature versus nurture? Consequences of short captivity in early stages

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