Wayne A Hubert

• PhD
• Professor Emeritus at University of Wyoming

Fisheries professionals can learn from animals such as the coyote when contemplating what is needed to survive the constant and accelerating changes occurring in the world and particularly in our profession. We are taught the skills we need from those who have experience. Within the professional world, we call people who teach us survival skills ou...

The effects of multiple nonnative piscivore species on native prey species in lentic systems are poorly understood. We studied the relative predation risks posed by two piscivorous salmonids (brown trout Salmo trutta and lake trout Salvelinus namaycush) to endemic roundtail chub Gila robusta in two lakes within the upper Colorado River basin. Gill...

Passive capture techniques involve the capture of fishes or other aquatic animals by entanglement, entrapment, or angling devices that are not actively moved by humans or machines while the organisms are being captured (Lagler 1978). The behavior and movements of the animals themselves result in their capture. The techniques used in passive samplin...

Although roundtail chub (Gila robusta) is generally considered a riverine species, 6 natural lakes in the upper Green River basin, Wyoming, have resident populations of this fish. In 2 of the lakes, Halfmoon and Little Halfmoon, we investigated the ecology of resident roundtail chub, including their habitat use, diet, weight—length relationships, g...

We assessed variation in longitudinal distributions of native and introduced fishes and their occurrences in different habitat types downstream from Boysen Dam in the Bighorn River, Wyoming. The closure of Boysen Dam in 1952 and construction of three downstream water diversion dams have led to channel changes in the Bighorn River causing reductions...

Reach-scale stream slope and the structure of associated physical habitats are thought to affect trout populations, yet previous studies confound the effect of stream slope with other factors that influence trout populations. We isolated the effect of stream slope on trout populations by sampling reaches immediately upstream and downstream of 23 ma...

Using the MARK VI standpipe in a substrate-filled flume under constant flow conditions, we found significant differences in permeability readings made by different people at four of five sites. Coefficients of variation at each site ranged from 27 to 79%. Readings usually varied greatly for each person at each site. To detect a 10% change in the me...

We compared samples collected from 10 substrates of various compositions with a single-probe freeze-core sampler, a triple-probe freeze-core sampler, a McNeil sampler, and a shovel. The accuracy with which these devices sampled particles larger than 50 mm in diameter varied; they were oversampled by the freeze-core devices, sampled in proportion to...

Summer habitat use and relative abundances of different size classes of yellow perch (Perca flavescens) were determined using gill nets set in the main basin, deep bays, and shallow bays of a lake. Niche overlap indices were used to quantify resource use patterns. Size classes spatially segregated into different habitats, but not different depths w...

We assessed changes in proximate body composition, wet mass, and the occurrence of mortality among sedentary and actively swimming (15 cm/s) juvenile rainbow trout (Oncorhynchus mykiss) (120–142 mm total length) that were held at 4.0, 7.5, or 15.0 °C and fasted for 140 days. Warmer water temperatures and swimming activity accentuated declines in li...

We assessed the relation of three measures of habitat to the distribution of four species of Salmonidae, cutthroat trout (Oncorhynchus clarki), brook trout (Salvelinus fontinalis), brown trout (Salmo trutta), and rainbow trout (Oncorhynchus mykiss), in streams of the central Rocky Mountains. We examined whether single measures of three habitat dime...

Surgically implanted dummy transmitters were expelled from the body cavity of 13 of 22 rainbow trout Salmo gairdneri within 42–175 d after they were implanted. Encapsulation of the dummy transmitters by the intestine and passage through the anus appeared to be the mechanism of expulsion.

Stream-dwelling fish face highly-variable environmental conditions from fall to winter due to fluctuations in water temperatures, discharge, and ice conditions. We provide an in-depth description of the interactions between these complex environmental conditions and behaviors of stream-dwelling salmonids during winter. Fisheries managers should be...

For populations of cutthroat trout Oncorhynchus clarkii, isolation in headwater streams may provide protection from invasion by nonnative species but also may enhance a population's vulnerability to extirpation. We assessed the risk of extirpation for eight Colorado River cutthroat trout O. clarkii pleuriticus populations isolated above water diver...

ABSTRACT  Sagebrush (Artemisia spp.)-dominated habitats in the western United States have experienced extensive, rapid changes due to development of natural-gas fields, resulting in localized declines of greater sage-grouse (Centrocercus urophasianus) populations. It is unclear whether population declines in natural-gas fields are caused by avoidan...

The purpose of this chapter is to provide a summary of issues and findings related to the potential effects of coalbed natural gas (CBNG) development on fish and other aquatic resources. We reviewed CBNG issues from across the United States and used the Powder River Basin of Wyoming as a case study to exemplify some pertinent issues. The quality of...

Abstract Low-head dams in arid regions restrict fish movement and create novel habitats that have complex effects on fish assemblages. The influence of low-head dams and artificial wetlands on fishes in Muddy Creek, a tributary of the Colorado River system in the USA was examined. Upstream, fish assemblages were dominated by native species includin...

Abstract Movements by adult cutthroat trout, Oncorhynchus clarkii (Richardson), were assessed from autumn to summer in the Salt River watershed, Wyoming-Idaho, USA by radio telemetry. Adult cutthroat trout were captured during September and October 2005 in the main stem of the Salt River, surgically implanted with radio transmitters, and tracked th...

Bluehead sucker (Catostomus discobolus) and flannelmouth sucker (Catostomus latipinnis) populations are declining throughout these species' native ranges in the Upper Colorado River Basin. In order to conserve these populations, an understanding of population dynamics is needed. Using age estimates from pectoral fin rays, we describe age and growth...

Hybridization with nonnative fishes is a major factor influencing the status of native catostomids in the Colorado River basin. In Wyoming, hybridization with nonnative white suckers Catostomus commersonii is a particular concern in the conservation of native bluehead suckers C. discobolus and flannelmouth suckers C. latipinnis. The purpose of this...

Peces nativos de Upper Colorado River Basin han experimentado una decadencia substancial en abundancia y distribución, y han sido eliminados de la mayor parte del Estado de Wyoming. Muddy Creek, en la parte sur central de Wyoming (la cuenca del Little Snake River), contiene poblaciones simpátricas del charalito aleta redonda (Gila robusta), y de lo...

We investigated the effects of constructed instream structures on movements and demographics of bluehead suckers Catostomus discobolus, flannelmouth suckers C. latipinnis, and roundtail chub Gila robusta in the upstream portion of Muddy Creek, an isolated headwater stream system in the upper Colorado River basin of Wyoming. Our objectives were to (...

We assessed the distributions of three species of conservation concern, bluehead sucker (Catostomus discobolus), flannelmouth sucker (Catostomus latipinnis), and roundtail chub (Gila robusta), relative to habitat features across a headwater tributary system of the Colorado River basin in Wyoming. We studied the upper Muddy Creek watershed, Carbon C...

The genetic impacts of hybridization between native and introduced species are of considerable conservation concern, while the possibility of reticulate evolution affects our basic understanding of how species arise and shapes how we use genetic data to understand evolutionary diversification. By using mitochondrial NADH dehydrogenase subunit 2 (ND...

The Little Wind River drainage in Wyoming is a relatively small unimpounded river system inhabited by native saugers Sander canadensis. Radio telemetry was used to assess habitat use and movement patterns by adult saugers in the river system from fall through early summer. Fifty-four adult saugers were captured during fall 2004, surgically implante...

Black spot is a common disease syndrome of freshwater fishes. This study provides information on the rank of density of the black spot agent and opercular bone alterations associated with at least one digenean, Uvulifer sp., infecting native and non-native catostomids and cyprinids of the Upper Colorado River Basin. We evaluated the density rank of...

Tricame methanesulfonate (MS-222) and CO2 are anesthetics that can be legally used in fisheries work in the United States, but they are limited in their field applications. A mandatory 21-d withdrawal period is required for fish exposed to MS-222. Carbon dioxide is not approved by the U.S. Food and Drug Administration, but it is a "low regulatory p...

We assessed longitudinal variation in small fish assemblages in the Wind River watershed upstream from Boysen Reservoir, Wyoming and into the reservoir. Twenty-six species were found in the study area, and 12 of the species were believed to have been introduced since settlement by Europeans. Additions and losses of fish species occurred with downst...

Understanding the population dynamics of native and nonnative fishes is critical for guiding and evaluating management activities, but obtaining information on population dynamics is often dependent on identifying structures that provide precise estimates of age. We examined age estimation using various hard structures for native bluehead suckers C...

This study was conducted to describe the distributions of both native and nonnative fishes and to identify spatial patterns in fish assemblage structure of Muddy Creek in the upper Colorado River basin of Wyoming using data collected from 77 reaches during 1999–2004. Fish assemblages in high-elevation reaches were characterized by brook trout (Salv...

Native fishes of the upper Colorado River basin (UCRB) have declined in distribution and abundance due to habitat degradation and interactions with nonnative fishes. Consequently, monitoring populations of both native and nonnative fishes is important for conservation of native species. We used data collected from Muddy Creek, Wyoming (2003–2004),...

Abstract  Fisheries research and management in North America have focused largely on sport fishes, but native non-game fishes have attracted increased attention due to their declines. The Warmwater Stream Assessment (WSA) was developed to evaluate simultaneously both fish and habitat in Wyoming streams by a process that includes three major compone...

Assessment of habitat and fish assemblages to determine the extent of anthropogenic alterations and define conditions relative to management goals is an important activity of management agencies. Assessment activities have been traditionally conducted at relatively small spatia scales (e.g., reaches and channel units), but many problems facing mana...

The abundance of adult saugers Sander canadensis was estimated over 179 km of continuous lotic habitat across a watershed on the western periphery of their natural distribution in Wyoming. Three-pass depletions with raft-mounted electrofishing gear were conducted in 283 pools and runs among 19 representative reaches totaling 51 km during the late s...

Environmental gradients occur with upstream progression from plains to mountains and affect the occurrence of native warmwater fish species, but the relative importance of various environmental gradients are not defined. We assessed the relative influences of elevation, channel slope, and stream width on the occurrences of 15 native warmwater fish...

Spatial and temporal variations in salmonid catch per unit effort (C/f) may affect monitoring efforts in lakes and reservoirs. This study evaluated the spatial and temporal variation in gill-net C/f and length structure of captured salmonids in nearshore (≤7.6-m bottom depth) and offshore (>7.6-m bottom depth) areas of two Wyoming reservoirs. Float...

We propose a new method for developing standard-weight (Ws) equations for use in the computation of relative weight (Wr) because the regression line–percentile (RLP) method often leads to length-related biases in Ws equations. We studied the structural properties of Ws equations developed by the RLP method through simulations, identified reasons fo...

There is little information on the winter features of salmonid habitats associated with constructed instream structures to provide guidance when planning habitat improvement projects. We assessed winter habitat features for trout of the genera Oncorhynchus and Salvelinus in pools associated with two types of instream structures constructed on a low...

We investigated relationships between the absence of salmonids and low summer water temperatures across a 150-km Rocky Mountain watershed. A model predicting maximum July water temperature (MJT) from measurements of perennial stream length, wetted width, and midrange basin elevation was developed from temperature data obtained at 20 sites across th...

Native cutthroat trout (Oncorhynchus clarki) in the Snake River watershed use streams formed by large springs for spawning and nursery habitat. Several spring streams have been modified to enhance abundance of adult salmonids, but the habitat associations of age-0 cutthroat trout in these systems are undescribed. We assessed the frequency of collec...

The Biotic-Abiotic Constraining Hypothesis (BACH) suggests that biotic interactions can have an overriding negative influence on a fish species, even when abiotic conditions are suitable. The abundance of a fish species is predicted to be largely regulated by abiotic habitat characteristics when densities of predators or competitors are low. Howeve...

Understanding factors related to the occurrence of species across multiple spatial and temporal scales is critical to the conservation and management of native fishes, especially for those species at the edge of their natural distribution. We used the concept of hierarchical faunal filters to provide a framework for investigating the influence of h...

Assessment of habitat and fish assemblages to determine the extent of anthropogenic alterations and define conditions relative to management goals is an important activity of management agencies. Assessment activities have been traditionally conducted at relatively small spatial scales (e.g., reaches and channel units), but many problems facing man...

Factors affecting the occurrence of saugers Sander canadensis were studied throughout the Wind River basin, a high-elevation watershed (>1,440 m above mean sea level) on the western periphery of the species' natural distribution in central Wyoming. Adult saugers appeared to have a contiguous distribution over 170 km of streams among four rivers in...

Understanding the upstream and downstream effect of impoundments on stream fish assemblages is important in managing fish populations and predicting the effects of future human activities on stream ecosystems. We used information collected over a 41-year period (1960-2001) to assess changes in fish assemblage structure resulting from impoundment of...

We evaluated the effects of body size, water temperature, and sustained swimming activity on swimming performance and the effects of exhaustive exercise on mortality of fasted juvenile rainbow trout. Fasting caused swimming performance to decline more rapidly for small fish than large fish, and warmer water temperatures and sustained swimming activ...

Habitat use and movements of 25 adult cutthroat trout Oncorhynchus clarkii and 25 adult brook trout Salvelinus fontinalis from fall through winter 2002–2003 were assessed by means of radiotelemetry in a 7-km reach of a Rocky Mountains foothills stream. Temporal dynamics of winter habitat conditions were evaluated by regularly measuring the features...

Fish and habitat were sampled from 110 reaches in the Salt River basin (Idaho and Wyoming) during 1996 and 1997 to assess patterns in fish assemblage structure across a Rocky Mountain watershed. We identified four dis- tinct fish assemblages using cluster analysis: (1) allopatric cutthroat trout (Oncorhynchus clarki (Richardson, 1836)); (2) cutthro...

Stream temperature is a fundamental physical factor that affects the distribution and abundance of salmonids, but empirical inconsistencies exist regarding the nature of this relationship in wild populations. We sampled trout populations composed primarily of cutthroat trout Oncorhynchus clarki but also including brown trout Salmo trutta and brook...

The cutthroat trout (Oncorhynchus clarki) was the only endemic salmonid species across most of the western United States, and it has severely declined largely due to introduction and bioinvasion by non-native salmonid species. However, the ecological, social, and economic consequences of cutthroat trout declines and replacement by non-native salmon...

Alternatives to electrofishing are needed for sampling sexually mature rainbow trout Oncorhynchus mykiss during the spawning season in large Alaskan rivers. We compared hook and line, beach seining, and actively fished gill nets as sampling tools. Beach seining and active gill netting yielded similar catch rates, length frequencies, and sex ratios...

We propose a new method for assessing length-related biases in standard weight (Ws) equations computed by the regression-line−percentile method. We evaluated the performance of the new method relative to two previous methods for assessing length-related biases using 15 data sets from which Ws equations have been computed. The new method detected po...

We assessed factors related to the occurrence of allopatric and sympatric Paiute Sculpin (Cottus beldingi) and Mottled Sculpin (Cottus bairdi) in the Salt River water- shed of Wyoming and Idaho, 1996-1997. Sympatric occurrences of Paiute Sculpin and Mottled Sculpin were found in downstream segments of tributaries across a wide range of elevations,...

The hypothesis that body size and swimming velocity affect proximate body composition, wet mass and size-selective mortality of fasted fish was evaluated using small (107 mm mean total length, LT) and medium (168 mm mean LT) juvenile rainbow trout Oncorhynchus mykiss that were sedentary or swimming (c. 1 or 2 body lengths-1) and fasted for 147 days...

This study was conducted to assess the influence of elevation and stream width on the occurrence of 28 native and six exotic fish species using data collected (1954–2003) from 1,114 stream reaches in Wyoming. Medians and ranges of elevation and stream width were used to assess how elevation and stream width influenced the occurrence of individual s...

We used data from 91 stream reaches in the Missouri River drainage of Wyoming to determine whether abiotic and biotic factors were related to the abundance of four cyprinid species associated with turbid-river environments: flathead chub Platygobio gracilis, sturgeon chub Macrhybopsis gelida, plains minnow Hybognathus placitus, and western silvery...

We studied spawning ecology of cutthroat trout (Oncorhynchus clarki) in streams that originate as springs along the Salt River, a Snake River tributary in western Wyoming. We assessed (1) relative numbers of upstream-migrant and resident adults present during the spawning period in spring streams, (2) influence of habitat modification on use of spr...

We compared the performance of Yellowstone cutthroat trout Oncorhynchus clarki bouvieri broodfish when fed a diet with corn Zea mays gluten meal, wheat Triticum spp. gluten meal, and krill Euphausia superba protein sources relative to two fish meal diets. We hypothesized that the plant-and-krill-based diet would lead to a greater bioavailability of...

Few differences in habitat use were observed between cutthroat trout and brown trout during winter in the Shoshone River, a regulated river in northwestern Wyoming. Radio-tagged fish of 20-30 cm total length were found in pool habitat five to six times more frequently than would be expected if they were using pools in proportion to pool availabilit...

Allacustrine rainbow trout move downstream from Naknek Lake into the Naknek River to spawn, and become vulnerable to angling during the spawning season. Regulations, including an annual angling closure from 10 April through 7 June, have been implemented to protect spawning fish from angling mortality, but the synchrony of the angling closure to the...

We compared abundance and length structure estimates of cutthroat trout (Oncorhynchus clarki) and brown trout (Salmo trutta) of 15 cm total length or greater obtained by snorkeling in stream pools with estimates obtained by depletion electrofishing. We sampled 12 pools in each of two streams formed by large springs in the Salt River Valley of weste...

The physiological traits that allow fish to survive periods of limited food resources are poorly understood. We assessed changes in proximate body composition, relative organ mass, blood metabolites, and relative weight (Wr) of sedentary and actively swimming (15 cm/s) juvenile rainbow trout (154–182 mm total length) over 147 d of fasting. Fasting...

High-mountain lakes provide important fisheries in the Rocky Mountains; therefore we sought to gain an understanding of the relationships among environmental factors, accessibility to anglers, stocking rates, and features of stocks of cutthroat trout Oncorhynchus clarki in high-mountain lakes of the Bighorn Mountains, Wyoming. We sampled fish with...

Fisheries managers often assess body condition using relative weight (Wr) because it provides a comparative measure of fish plumpness among individuals and populations. However, it is not known whether the morphological information that Wr summarizes reflects physiological measures, such as relative lipid reserves, in rainbow trout Oncorhynchus myk...

There are numerous demands for the limited water supplies in the Rocky Mountain (USA) region, and controversies surrounding instream flows abound. A specific problem involves water diversions (i.e., small dams that shunt water out of stream channels) during the summer irrigation season. We developed an approach to assess the effects of restoration...

We examined the effects of thermal shock on poststocking survival of fingerling rainbow trout Oncorhynchus mykiss (mean total length, 99 mm; mean weight, 10 g), some of which were thermally tempered at stocking and others not. In one experiment we assessed survival when fish experienced increases in water temperature from 8°C to 24°C at two temperi...

We assessed habitat availability and habitat use by subadult cutthroat trout Oncorhynchus clarki and brown trout Salmo trutta during a four-stage flow manipulation in the Shoshone River, Wyoming, to determine how the physical characteristics of a medium-size river and the habitat use and movement patterns of subadult trout change in response to dec...

Fisheries managers have often suggested that survival of trout during the winter is a major factor affecting population densities in many stream ecosystems in the Rocky Mountains. In Wyoming, trout population reductions from fall to spring in excess of 90% have been documented in some reservoir tailwaters. Though biologists have surmised that these...

There are many examples of how standardization of procedures in production and data collection have led to remarkable advances in industry and science, but standardization is lacking regarding protocols for sampling fish populations in inland, freshwater systems. Reasons given why biologists often resist standardized sampling protocols include perc...

We assessed endemic age-0 cutthroat trout Oncorhynchus clarki for evidence of pathology associated with Myxobolus cerebralis in two streams formed by springs in western Wyoming. We hypothesized that the location of spawning sites in spring streams would affect the extent of exposure of cutthroat trout fry to M. cerebralis triactinomyxons (tams), oc...

Weight-length relationships provide a tool to assess the body condition of brown trout (Salmo trutta) populations inhabiting stream reaches where stressors, such as metals, have chronic, sub-lethal toxic impacts. A previously published brown trout standard-weight equation, Ws, overestimated Colorado brown trout weights. Weight-length data from 16 C...

Geothermal springs in or adjacent to streams can contribute hydrogen sulfide (H2S) and affect distributions of fish. We assessed the effects of H2S, relative to discharge, on the locations and movements of cutthroat trout Oncorhynchus clarki and brown trout Salmo trutta in a regulated river in northwestern Wyoming. Concentrations of H2S as low as 0...

We studied three tailwaters in Wyoming from October 1997 through February 1998 to determine whether body conditions of stocked, subadult rainbow trout Oncorhynchus mykiss or cutthroat trout O. clarki declined from fall through winter and to assess whether lack of food in stomachs might be related to any declines. Body conditions of rainbow trout in...

We investigated the effects of geothermally influenced waters on the distribution of rainbow trout, Oncorhynchus mykiss, and brown trout, Salmo trutta, in the Firehole River and its tributaries in Yellowstone National Park (WY, USA) from June 1997 to June 1998. Geothermal features in the Firehole River basin elevate mineral content and temperature...

We assessed relative weight (Wr) distributions among 291 samples of stock-to-quality-length brook trout Salvelinus fontinalis, brown trout Salmo trutta, rainbow trout Oncorhynchus mykiss, and cutthroat trout O. clarki from lentic and lotic habitats. Statistics describing Wr sample distributions varied slightly among species and habitat types. The a...

We used aerial thermography to determine the location of sandhill crane (Grus canadensis) roosting sites during a single night over a 142-km reach of the Platte River, Nebraska. We assessed the influences of human disturbance features, screening of disturbance features by woody vegetation, distance to surrounding cropland of various types and chann...

We studied how the features of mountain watersheds interact to cause gradients in three stream attributes: baseflow stream widths, total alkalinity, and stream slope. A priori hypotheses were developed before being tested in a series of path analyses using data from 90 stream reaches on 24 second- to fourth-order streams across a fifth-order Rocky...

Temperature is an important variable structuring lotic biotas, but little is known about how montane landscapes function to determine stream temperatures. We developed an a priori hypothesis that was used to predict how watershed elements would interact to affect stream temperatures. The hypothesis was tested in a series of path analyses using temp...

We developed a standard-weight (Ws) equation for brown trout (Salmo trutta) in lentic habitats by applying the regression-line-percentile technique to samples from 49 populations in North America. The proposed Ws equation is log Ws = −5.422 + 3.194 log10 TL, when Ws is in grams and TL is total length in millimeters. The English-unit equivalent is l...

Weight and length data were obtained for 113 populations of brook trout Salvelinus fontinalis across the species' geographic range in North America to estimate a standard-weight (Ws) equation for this species. Estimation was done by applying the regression-line-percentile technique to fish of 120-620 mm total length (TL). The proposed metric-unit (...

Patterns of selection and evolution of renewable resource management paradigms appear when strategies are considered across a temporal scale. The roles of renewable resource managers were established during the early twentieth century and have since evolved. Autocratic natural-science-based management (ANM) of renewable resources was institutionali...

We developed standard-weight (Ws) equations for kokanee (lacustrine Oncorhynchus nerka), golden trout (O. aguabonita), and bull trout (Salvelinus confluentus) using the regression-line-percentile technique. The Ws equation for kokanee of 120–550 mm TL is log10 Ws = −5.062 + 3.033 log10 TL, when Ws is in grams and TL is total length in millimeters;...

We investigated the availability of drifting invertebrates and the stomach contents and body conditions of stocked (hatchery) and naturally spawned (wild) juvenile (20-25 cm total length) rainbow trout from fall through winter in the Big Horn River downstream from Boysen Dam in Wyoming. When the density and biomass of drifting invertebrates decline...

We assessed relations between measurements of streamside features on site and from aerial photographs for determining the amount of cover available to brown trout Salmo trutta and other salmonids Oncorhynchus spp. in alluvial valley streams in Wyoming. We found that a riparian vegetation index (RVI) measured from aerial photographs accounted for mu...

Most subspecies of interior cutthroat trout Oncorhynchus clarki have suffered dramatic declines in range and number. We assessed the status of genetically pure Yellowstone cutthroat trout O. clarki bouvieri on predominantly public lands in three major watersheds of northwestern Wyoming (Greybull River and North and South Forks of the Shoshone River...

Trout counts and length-class frequencies determined by snorkeling were compared with estimates determined by electrofishing in 25 reaches of small (≤11-m wetted width) streams of the Bighorn Mountains, Wyoming. The numbers of trout (brook trout Salvelinus fontinalis, rainbow trout Oncorhynchus mykiss, and cutthroat trout O. clarki) counted by snor...