Predicting cutthroat trout (Oncorhynchus clarkii) abundance in high-elevation streams: revisiting a model of translocation success

2005 ◽  
Vol 62 (10) ◽  
pp. 2399-2408 ◽  
Author(s):  
Michael K Young ◽  
Paula M Guenther-Gloss ◽  
Ashley D Ficke
Keyword(s):  
Population Size ◽  
Habitat Complexity ◽  
Cutthroat Trout ◽  
High Elevation ◽  
Stream Length ◽  
Oncorhynchus Clarkii ◽  
Abundance Estimates ◽  
Population Sizes ◽  
Bankfull Width ◽  
Habitat Variables

Assessing viability of stream populations of cutthroat trout (Oncorhynchus clarkii) and identifying streams suitable for establishing populations are priorities in the western United States, and a model was recently developed to predict translocation success (as defined by an index of population size) of two subspecies based on mean July water temperature, pool bankfull width, and deep pools counts. To determine whether the translocation model applied to streams elsewhere with more precise abundance estimates, we examined the relation between electrofishing-based estimates of cutthroat trout abundance and these habitat variables plus occupied stream length. The preferred model was (population size)1/2 = 0.00508(stream length (m)) + 5.148 (N = 31). In contrast, a model based on data from the original translocation model included stream temperature and deep pool counts as variables. Differences in models appear to largely have a methodological rather than biological basis. Additional habitat coupled with increased habitat complexity may account for the form of the abundance – stream length relation in the electrofishing-based model. Model-derived estimates imply that many cutthroat trout populations are below thresholds associated with reduced risk of extinction. We believe that this model can reduce uncertainty about projected population sizes when selecting streams for reintroductions or evaluating unsampled streams.

Evolutionary potential but not extinction risk of Lahontan cutthroat trout (Oncorhynchus clarkii henshawi) is associated with stream characteristics

2012 ◽  
Vol 69 (4) ◽  
pp. 615-626 ◽  
Author(s):  
Mary M. Peacock ◽  
Ned A. Dochtermann
Keyword(s):  
Population Size ◽  
Effective Population Size ◽  
Extinction Risk ◽  
Spatial Scales ◽  
Cutthroat Trout ◽  
Effective Population ◽  
Evolutionary Potential ◽  
Oncorhynchus Clarkii ◽  
Lahontan Cutthroat Trout ◽  
Habitat Variables

Habitat fragmentation represents a major extinction threat for species of all taxa. Isolated populations have a higher risk of local extinction because of environmental variability and demographic processes associated with small populations. Here we examine the relationships among isolation, habitat size, habitat characteristics and variability, and genetic effective population size with extinction risk for 10 isolated and three interconnected populations of Lahontan cutthroat trout ( Oncorhynchus clarkii henshawi ) sampled from throughout their range. Contrary to expectations, we did not find a relationship between most habitat variables and extinction risk. However, we did find strong relationships between habitat variables and genetic effective population size, including a significant negative correlation between pool density and effective population size. Small effective population sizes can result in reduced genetic variation and losses of evolutionary potential and adaptability to changing environments. The absence of strong habitat correlates with extinction risk — despite an observed relationship with effective population size — highlights the need to consider habitat diversity at multiple spatial scales when considering management scenarios to both promote population persistence and maintain evolutionary relevance.

It’s complicated…Environmental DNA as a predictor of trout and char abundance in streams

2020 ◽  
Author(s):  
Adam J. Sepulveda ◽  
Robert Al-Chokhachy ◽  
Matthew B Laramie ◽  
Kyle Crapster ◽  
W Ladd Knotek ◽  
...  
Keyword(s):  
Cutthroat Trout ◽  
Environmental Dna ◽  
Fish Abundance ◽  
Bull Trout ◽  
Intermountain West ◽  
Salvelinus Confluentus ◽  
Oncorhynchus Clarkii ◽  
Habitat Monitoring ◽  
Abundance Estimates ◽  
Random Site

The potential to provide inferences about fish abundance from environmental (e)DNA samples has generated great interest. However, the accuracy of these abundance estimates is often low and variable across species and space. A plausible refinement is the use of common aquatic habitat monitoring data to account for attributes that influence eDNA dynamics. We therefore evaluated the relationships between eDNA concentration and abundance of bull trout (Salvelinus confluentus), westslope cutthroat trout (Oncorhynchus clarkii lewisi) and rainbow trout (O. mykiss) at 42 stream sites in the Intermountain West (USA and CAN) and tested if accounting for site-specific habitat attributes improved the accuracy of fish abundance estimates. eDNA concentrations were positively associated with fish abundance but these relationships varied by species and site and there was considerable variation unaccounted for. Random site-level differences explained much of this variation, but specific habitat attributes of those sites explained relatively small amounts of this variation. Our results underscore that either eDNA sampling or environmental characterization will require further refinement before eDNA can be used reliably to estimate fish abundance in streams.

scholarly journals Presence of Microplastics in the Food Web of the Largest High-Elevation Lake in North America

Water ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 264
Author(s):  
Stephanie C. Driscoll ◽  
Hayley C. Glassic ◽  
Christopher S. Guy ◽  
Todd M. Koel
Keyword(s):  
Food Web ◽  
Water Samples ◽  
Lake Trout ◽  
Cutthroat Trout ◽  
Terrestrial Ecosystems ◽  
High Elevation ◽  
Trophic Levels ◽  
Oncorhynchus Clarkii ◽  
Global Action ◽  
Yellowstone Cutthroat Trout

Microplastics have been documented in aquatic and terrestrial ecosystems throughout the world. However, few studies have investigated microplastics in freshwater fish diets. In this study, water samples and three trophic levels of a freshwater food web were investigated for microplastic presence: amphipods (Gammarus lacustris), Yellowstone cutthroat trout (Oncorhynchus clarkii bouvieri), and lake trout (Salvelinus namaycush). Microplastics and other anthropogenic materials were documented in water samples, amphipods, and fish, then confirmed using FTIR (Fourier-transform infrared) and Raman spectroscopy. Our findings confirmed the presence of microplastics and other anthropogenic materials in three trophic levels of a freshwater food web in a high-elevation lake in a national park, which corroborates recent studies implicating the global distribution of microplastics. This study further illustrates the need for global action regarding the appropriate manufacturing, use, and disposal of plastics to minimize the effects of plastics on the environment.

scholarly journals Using visual encounter data to improve capture-recapture abundance estimates

2020 ◽  
Author(s):  
Maxwell B. Joseph ◽  
Roland A. Knapp
Keyword(s):  
Population Size ◽  
Lower Bounds ◽  
Bayesian Approach ◽  
Individual Identification ◽  
Hierarchical Bayesian ◽  
Sampling Occasion ◽  
Demographic Rates ◽  
Abundance Estimates ◽  
Population Sizes ◽  
Capture Recapture

AbstractCapture-recapture studies are widely used in ecology to estimate population sizes and demographic rates. In some capture-recapture studies, individuals may be visually encountered but not identified. For example, if individual identification is only possible upon capture and individuals escape capture, visual encounters can result in failed captures where individual identities are unknown. In such cases, the data consist of capture histories with known individual identities, and counts of failed captures for individuals with unknown identities. These failed captures are ignored in traditional capture-recapture analyses that require known individual identities. Here we show that if animals can be encountered at most once per sampling occasion, failed captures provide lower bounds on population size that can increase the precision of abundance estimates. Analytical results and simulations indicate that visual encounter data improve abundance estimates when capture probabilities are low, and when there are few repeat surveys. We present a hierarchical Bayesian approach for integrating failed captures and auxiliary encounter data in statistical capture-recapture models. This approach can be integrated with existing capture-recapture models, and may prove particularly useful for hard to capture species in data-limited settings.

Influence of water temperature and biotic interactions on the distribution of Westslope Cutthroat Trout (Oncorhynchus clarkii lewisi) in a population stronghold under climate change

2020 ◽  
Author(s):  
Kadie B. Heinle ◽  
Lisa A. Eby ◽  
Clint C. Muhlfeld ◽  
Amber C. Steed ◽  
Leslie A. Jones ◽  
...  
Keyword(s):  
Climate Change ◽  
Climate Adaptation ◽  
Cutthroat Trout ◽  
Stream Temperature ◽  
High Elevation ◽  
Suitable Habitat ◽  
Bull Trout ◽  
Westslope Cutthroat Trout ◽  
Oncorhynchus Clarkii ◽  
Species Response

Climate warming is expected to have substantial impacts on native trout across the Rocky Mountains, but there is little understanding of how these changes affect future distributions of co-occurring native fishes within population strongholds. We used mixed-effects logistic regression to investigate the role of abiotic (e.g., temperature) and biotic factors (Bull Trout presence, Salvelinus confluentus) on distributions of Westslope Cutthroat Trout (Oncorhynchus clarkii lewisi; WCT) in the North Fork Flathead River, USA and Canada. The probability of WCT presence increased with stream temperature and decreased with channel gradient and Bull Trout presence, yet the effect of Bull Trout was reduced with increasing pool densities. Combining this model with spatially-explicit stream temperature projections, we predict a 29% increase in suitable habitat under high emissions through 2075, with gains at mid-elevation sites predicted to exceed Bull Trout thermal tolerances and high-elevation sites expected to become more thermally suitable for WCT. Our study illustrates the importance of considering abiotic and biotic drivers to assess species response to climate change, helping to guide local scale climate adaptation and management.

Abiotic conditions are unlikely to mediate hybridization between invasive rainbow trout and native Yellowstone cutthroat trout in a high-elevation metapopulation

2020 ◽  
Vol 77 (9) ◽  
pp. 1433-1445 ◽  
Author(s):  
Kurt C. Heim ◽  
Thomas E. McMahon ◽  
Steven T. Kalinowski ◽  
Brian D. Ertel ◽  
Todd M. Koel
Keyword(s):  
Rainbow Trout ◽  
Cutthroat Trout ◽  
High Elevation ◽  
Source Population ◽  
Full Spectrum ◽  
Oncorhynchus Clarkii ◽  
Abiotic Conditions ◽  
Management Intervention ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Yellowstone Cutthroat Trout

Understanding factors mediating hybridization between native and invasive species is crucial for conservation. We assessed the spatial distribution of hybridization between invasive rainbow trout (Oncorhynchus mykiss) and native Yellowstone cutthroat trout (Oncorhynchus clarkii bouveri) in the Lamar River of Yellowstone National Park using a paired telemetry and genetic dataset. Spawning populations containing hybrids (15/30) occupied the full spectrum of abiotic conditions in the watershed (stream temperature, stream size, runoff timing), including an intermittent stream that dried completely in late June, and mainstem spawning locations. Hybrids and rainbow trout occupied an entire high-elevation (∼2500–1900 m) tributary where rainbow trout ancestry was highest in headwaters and decreased downstream. Fluvial distance to this ostensible source population was the only covariate included in top hybridization models; effects of abiotic covariates and stocking intensity were relatively weak. In this watershed, abiotic conditions are unlikely to mediate continued hybridization. We conclude that management intervention is important for the persistence of nonhybridized Yellowstone cutthroat trout and highlight the value of pairing telemetry with genetic analysis to identify and characterize populations for hybridization assessments.

Application of a method for estimating effective population size and admixture using diagnostic single nucleotide polymorphisms (SNPs): implications for conservation of threatened Paiute cutthroat trout (Oncorhynchus clarkii seleniris) in Silver King Creek, California

2011 ◽  
Vol 68 (8) ◽  
pp. 1369-1386 ◽  
Author(s):  
Amanda J. Finger ◽  
Eric C. Anderson ◽  
Molly R. Stephens ◽  
Bernard P. May
Keyword(s):  
Oncorhynchus Mykiss ◽  
Population Size ◽  
Effective Population Size ◽  
Cutthroat Trout ◽  
Likelihood Method ◽  
Effective Population ◽  
Autosomal Snps ◽  
Single Nucleotide ◽  
Oncorhynchus Clarkii ◽  
Point Estimates

The threatened Paiute cutthroat trout ( Oncorhynchus clarkii seleniris , PCT) is endemic to Silver King Creek, California, USA, which was stocked with non-native trout beginning in 1930. Single nucleotide polymorphism (SNP) and microsatellite data reveal that the trout population in Silver King Creek is weakly structured and composed of introgressed California golden trout ( Oncorhynchus mykiss aguabonita , CAGT), hatchery rainbow trout ( Oncorhynchus mykiss , RT), and some native PCT. Two SNP groups were analyzed: (i) one mitochondrial and five autosomal SNPs, diagnostic between Lahontan cutthroat trout ( Oncorhynchus clarkii henshawi ) or PCT and CAGT or RT and (ii) one mitochondrial and five autosomal SNPs nearly diagnostic between CAGT and RT. The five autosomal cutthroat–rainbow SNPs were used to jointly estimate the cutthroat trout mixing proportion in Silver King Creek and effective population size (Ne) of the admixed population, using a coalescent-based maximum likelihood method. Given the stocking history of Silver King Creek, there are two different scenarios that bound the range of expected point estimates for Ne. We obtain point estimates of Ne = 150 and Ne = 750 for Silver King Creek under these two scenarios. This method will be useful in cases with differentiated taxa and in prioritizing conservation and restoration programs where the populations of concern are introgressed.

scholarly journals Effect of Pheromone Blend Components, Sex Ratio, and Population Size on the Mating of Cadra cautella (Lepidoptera: Pyralidae)

2020 ◽  
Vol 20 (6) ◽  
Author(s):  
Abeysinghe Mudiyanselage Prabodha Sammani ◽  
Dissanayaka Mudiyanselage Saman Kumara Dissanayaka ◽  
Leanage Kanaka Wolly Wijayaratne ◽  
William Robert Morrison
Keyword(s):  
Sex Ratio ◽  
Population Size ◽  
Management Practices ◽  
Mating Disruption ◽  
Current Knowledge ◽  
Mating Status ◽  
Cadra Cautella ◽  
Synthetic Chemicals ◽  
Population Sizes ◽  
Lepidoptera Pyralidae

Abstract The almond moth Cadra cautella (Walker), a key pest of storage facilities, is difficult to manage using synthetic chemicals. Pheromone-based management methods remain a high priority due to advantages over conventional management practices, which typically use insecticides. Cadra cautella females release a blend of pheromone including (Z, E)-9,12-tetradecadienyl acetate (ZETA) and (Z)-9-tetradecadien-1-yl acetate (ZTA). The effect of these components on mating of C. cautella and how response varies with the population density and sex ratio remain unknown. In this study, the mating status of C. cautella was studied inside mating cages under different ratios of ZETA and ZTA diluted in hexane and at different population sizes either with equal or unequal sex ratio. The lowest percentage of mated females (highest mating disruption [MD] effects), corresponding to roughly 12.5%, was produced by a 5:1 and 3.3:1 ratio of ZETA:ZTA. Populations with equal sex ratio showed the lowest percentage of mated females, at 20% and 12.5% under lower and higher density, respectively. The next lowest percentage of mated females was produced when the sex ratio was set to 1: 2 and 2:1 male:female, with just 25% and 22.5% of moths mated, respectively. This study shows that mating status of C. cautella is influenced by ZETA:ZTA ratio, sex ratio, and population size. This current knowledge would have useful implications for mating disruption programs.

scholarly journals EFFECTS OF POPULATION SIZE AND SELECTION INTENSITY ON SHORT-TERM RESPONSE TO SELECTION FOR POSTWEANING GAIN IN MICE

Genetics ◽  
1973 ◽  
Vol 73 (3) ◽  
pp. 513-530
Author(s):  
J P Hanrahan ◽  
E J Eisen ◽  
J E Legates
Keyword(s):  
Population Size ◽  
Selection Response ◽  
Selection Intensity ◽  
Realized Heritability ◽  
Family Selection ◽  
Effective Population ◽  
Population Sizes ◽  
Selection For ◽  
Selection Intensities ◽  
Term Response

ABSTRACT The effects of population size and selection intensity on the mean response was examined after 14 generations of within full-sib family selection for postweaning gain in mice. Population sizes of 1, 2, 4, 8 and 16 pair matings were each evaluated at selection intensities of 100% (control), 50% and 25% in a replicated experiment. Selection response per generation increased as selection intensity increased. Selection response and realized heritability tended to increase with increasing population size. Replicate variability in realized heritability was large at population sizes of 1, 2 and 4 pairs. Genetic drift was implicated as the primary factor causing the reduced response and lowered repeatability at the smaller population sizes. Lines with intended effective population sizes of 62 yielded larger selection responses per unit selection differential than lines with effective population sizes of 30 or less.

Estimation of Catchabilities and Population Sizes of Lobsters

1963 ◽  
Vol 20 (1) ◽  
pp. 59-88 ◽  
Author(s):  
J. E. Paloheimo
Keyword(s):  
Environmental Factors ◽  
Population Size ◽  
Atlantic Coast ◽  
Temperature Data ◽  
New Method ◽  
Bottom Temperature ◽  
Population Size Estimates ◽  
Population Sizes ◽  
Estimate Population Size ◽  
Size Estimates

Techniques of estimating population size, level of fishing, and the degree of dependence of fishing success on environmental factors are examined on the basis of tagging, catch and effort data. A new method is developed to estimate population size from catch, effort, and temperature data when the catchability varies with temperature.The methods of estimation discussed are applied to data collected from a number of lobster fisheries on Canada's Atlantic coast. Analysis confirms a relationship between the catchability of lobsters and bottom temperature. Differences in this relationship are found between areas and between tagged and untagged lobsters within areas. It is suggested that these differences are attributable to the differences in densities as well as to aggregations of lobsters and fishing. The effect of these aggregations on population size estimates is considered.Calculated average catchabilities at comparable temperatures are different for different areas. These differences are correlated with the numbers of trap hauls per day per square miles fished. It is suggested that the differences in the catchabilities might be due to interactions between units of gear not predicted by the customary relationship between catch and effort.

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