Reproductive characteristics of two kokanee stocks in tributaries to Flaming Gorge Reservoir, Utah and Wyoming

The charaeteristics of kokanee ( Oncorhynchus nerka ) spawning stocks in the Green River and Sheep Creek (tributaries to Flaming Gorge Reservoir) are described as observed in fall 1985 and spring 1986; the time of spawning; length, age, and sex structure of the stocks; fecundity and egg retention; density of eggs in redds; and the timing of downstream drift of emerging fry. The time of spawning, length-frequency distributions of spawning fish, and egg density in redds differed between the two stocks, but other differences were not observed.     

Parasites of the cutthroat trout, Salmo clarki, and longnose suckers, Catostomus catostomus, from Yellowstone Lake, Wyoming

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Host-parasite studies of Trichophrya infesting cutthroat trout ( Salmo clarki ) and longnose suckers ( Catostomus catostomus ) from Yellowstone Lake, Wyoming

Trichophrya sp. (Protozoa) on the gills of cutthroat trout ( Salmo clarki ) and longnose suckers ( Catostomus catostomus ) was studied using light and electron microscopy and tracer techniques. All cutthroat trout, 14 cm in total length and above, from Yellowstone Lake, Yellowstone National Park, Wyoming, were infested with the suctorian. No trichophryans were found on fry or fingerling cutthroat trout. Sixty percent of the examined longnose suckers from the same location were infested. Light microscopy disclosed extensive pathology of gill epithelium in longnose suckers infested with Trichophrya that was not observed for infested cutthroat trout. Electron micrographs show damage to immediate host gill cells by both parasites, depicted by a reduction and lack of mitochondria. Both parasites form attachment helices (0.52 × 0.04 μ m), which may originate in the protozoan cell membrane and function for maintenance of parasite position on the host cell. There was no uptake of 14 C, injected into host fish, via the attachment helices by the parasite that further substantiated the mechanical function for the spiral structure. Protozoan feeding on host tissue may be accomplished by use of necrotic gill tissue and mucus.        

The raccoon, Procyon Iotor, in Wyoming

Recent distribution maps show raccoon as occupying only the extreme eastern - northeastern portion of Wyoming. However, there is substantial evidence that raccoon are common throughout Wyoming and currently inhabit all the major and many of the minor drainages throughout Wyoming.     

Ecology of flannelmouth sucker in the Lee's Ferry tailwater, Colorado River, Arizona

We investigated ecology of flannelmouth sucker ( Catostomus latipinnis ) from 1992 to 1997 in the 26-km Lee's Ferry reach of the Colorado River immediately below Glen Canyon Dam, Arizona. We captured by electrofishing a total of 212 fish and recaptured 52 previously tagged by others. Flannelmouth sucker were captured throughout the tailwater but tended to aggregate about 5 km of the dam, possibly reflecting blockage of historic migration routes. Catch per hour of electrofishing did not differ among years but was greater from November to February than other periods, suggesting seasonal movements of flannelmouth sucker into the tailwater: Mean lengths and weights of fish did not differ among years or seasons. Length frequency analyses also indicated there were no significantly yearly trends in proportion of catch within size classes of fish. Mean condition differed only among seasons and was greatest in February, lowest in August, coinciding respectively with pre- and post-spawning periods of flannelmouth sucker in tributary just down from Lee's Ferry. Recaptured fish migrated from initial tagging locations 1.4-23.1 km downstream from Lee's Ferry. Fifty-nine percent of recaptured fish with known initial tagging locations increased in length, and fish tagged initially as subadults or adults, respectively, grew an average of 45.9 mm and 5.5 mm per year.     

Growth and reproduction of the flannelmouth sucker, Catostomus latipinnis, in the Upper Colorado River Basin, 1975-76

Growth rates estimated using the scale annuli of flannelmouth sucker, Catostomus latipinnis , did not differ between fish collected from the Gunnison and Colorado rivers, and the Green and Yampa rivers. However, body condition and fecundity were significantly greater in the former population. Age of first maturity for male and female fish from all rivers was IV; and most fish were mature by age VII. The smallest mature female collected was 405 mm, and the smallest mature male was 391 mm total length. Fecundity ranged from 4,000 ova in fish 450 mm long to 40,000 ova in a 500-mm fish: mean ovum diameter was 2.39 mm. Ripe male flannelmouth suckers were collected from early April through June; ripe females were collected from both study areas during May and early June.         

Eimeria sp. (Apicomplexa: Eimeriidae) from Wyoming ground squirrels Spermophilus elegans , and white-tailed prairie dogs, Cynomys leucurus , in Wyoming

Six species of the coccidian genus Eimeria ( E. larimerensis [prevalence = 17%], E. bilamellata [12%] E. beecheyi [34%], E. morainensis [43%], E. callospermophili [21%], and E. spermophili [5%]) were recovered from Wyoming ground squirrels ( Spermophilus elegans elegans ) collected during 1983, 1984, 1985, and 1986. Infected ground squirrels were found to harbor from one to five species simultaneously. The 1007 hosts examined were collected from two different habitats: (1) a xeric desert shrub-steppe and (2) an irrigated alfalfa-brome field. All species of Eimeria occurred at each study site during all years, although the prevalence of each species varied between years. This is the first report of these congeries of species infecting this host. In a second study of sympatric populations of Wyoming ground squirrels and white-tailed prairie dogs ( Cynomys leucurus ), found three species of Eimeria present in both host populations ( E. beecheyi [white-tailed prairie dog prevalence = 83%, Wyoming ground squirrel = 52%], E. morainensis [22%, 52%], and E. bilamellata [17%, 10%]). This is the first report of these three species infecting white-tailed prairie dogs. Eimeria larimerensis was found in Wyoming ground squirrels but not in prairie dogs.     

Checklist of Recent Mollusca of Wyoming, USA

Wyoming lacks a rich molluscan fauna due to its considerable elevation, extremes of temperature, the short period between killing frosts, scanty, moisture, and intermittent creeks. Recent mollusks found in the state total 42 genera (109 species), including 6 genera (23 species) of bivalves, 15 genera (42 species) of freshwater gastropods, and 21 genera (44 species) of land gastropods. Synonymy, the counties in which each species was collected, and habitat notes are given.     

Diplostomiasis in native and introduced fishes from Yellowstone Lake, Wyoming

Totals of 101 native Yellowstone cutthroat ( Oncorhynchus clarki bouvieri ), 27 introduced lake trout ( Salvelinus namaycush ), and 40 introduced longnose sucker ( Catostomus catostomus ) from Yellowstone Lake, Wyoming, USA, were examined for eye flukes. Metacercariae of the trematode fluke Diplostomum were in vitreous humor and/or lens of 94% of Yellowstone cutthroat trout, 92% of lake trout, and 78% of longnose sucker. Longnose sucker had 7% prevalence of infection in both lens and vitreous humor of metacercariae, while Yellowstone cutthroat trout had 3% and lake trout 8%. Diplostomum spathaceum was in lens tissue of 5% of infected Yellowstone cutthroat trout and 93% of longnose sucker; Diplostomum baeri was in vitreous humor of 92% each of infected Yellowstone cutthroat trout and lake trout. Morphological characteristics indicate that a single species infected the lens of Yellowstone cutthroat trout and longnose sucker, while another species infected lake trout. Impacts of the parasite interchange between native and introduced fishes of Yellowstone Lake, Wyoming, are unknown but should be monitored each year.     

Age, growth, and food habits of tui chub, Gila bicolor, in Walker Lake, Nevada

At Walker Lake, Nevada, tui chub were collected 1975–1977 for analysis of age, growth rate, and food habits. The fork length (FL) – scale radius (SR) relationship was linear and described by the equation FL = 4.44 + 3.17 (SR). Age I, II, III, and IV chub were 116, 176, 218, and 242 mm fork length, respectively. Maximum longevity was six years. The length weight relationship was defined by the log transformed linear equation log weight = - 4.65 + 2.93 (log FL). Chub collected from pelagic regions ate mostly zooplankton, whereas chub collected from littoral areas had a diet of zooplankton and benthic organisms.         

Winter habitat-use pattern of elk, mule deer, and mosse in southwestern Wyoming

Habitat-use patterns of mule deer, elk, and moose were determined on two winter range near Kemmerer, Wyoming. Mule deer used areas with the least snow depth and dominated by sagebrush. Elk were located more often than expected on wind-swept hills but used sagebrush communities more frequently as snow depths increased. Moose were generally found associated with broad, riparian zones. All three species occasionally used the same area but differed in their use of specific vegetation types and topography.     

Time budgets of Wyoming ground squirrels, Spermophilus elegans

Time budget of free-living adult Spermophilus elegans differed significantly from that of juveniles in the Front Range of the Rockies during 1974–1975. No differences were found between males and females. Hour of day, day since emergence, air temperature, cloud cover, and presence of predators all correlated with the frequency of various components of the time budget.     

Morphology and taxonomy of Klamath Basin suckers (Catostomidae)

We examined morphology of 4 sucker species (Catostomidae) from Klamath and Rogue River basins, Oregon and California. Different pairs of these species have been suspected of hybridizing, and field biologists have experienced difficulty identifying individuals in some areas. The suite of morphological characters used for initial identification was poorly supported by other morphometric characters but well supported by meristic characters, especially when analyses were restricted geographically. In some species sexual dimorphism was evident, with males having longer pectoral fins and females having longer pre-anal counts and measurements. Each species showed geographic differentiation, either between the Lost River subbasin and other Klamath subbasins or between Klamath and Rogue basins. Classification was most difficult for Catostomus snyderi , which was frequently misclassified as all other species, but especially as Chasmistes brevirostris . Despite this, the 2 species are ecologically segregated in the upper subbasins with lake-spawning Ch. brevirostris spatially segregated and river-spawning Ch. brevirostris temporally segregated from river-spawning C. snyderi . We discuss the possibility that a large-headed, thin-lipped species has become extinct in Upper Klamath Lake and alternatively suggest that the form could represent an ecophenotype of Ch. brevirostris that is no longer produced in hypereutrophic Upper Klamath Lake.     

Demographic characteristics of American marten populations in Jackson Hole, Wyoming

Some American marten population characteristics (numbers, density, body weights, sex and age ratios, natality, mortality-survivorship, immigration-emigration, home ranges) were studied at four sites in the southern part of the Greater Yellowstone Ecosystem, Teton County, Wyoming, in 1975-1979. Ninety-eight different martens were examined. Males (n = 25) weighed 1,111 g (± 110 SD, range 875-1,235), whereas females (n = 17) averaged 743 g (± 83 SD, range 600-900). Live-trapping showed sex ratios of 1.5M:1.0F, whereas carcasses showed 3.0M:1.0F. Of 27males that were aged, 12 (44%) were less than 1 year old and 2 were 9-10 years old. Of 10 females, 6 were less than 1 year old and 1 was 12-13 years old. The mean length of time a male was present on the major study area was 144 days (± 266 SD, range 1-1,364), and for females it was 145 days (± 45 SD, range 1-560). Home ranges for six males averaged 3.2 km 2 (± 20 SD, range 0.7-5.8) on the main study area. Some management implications are given.     

Bald eagle winter survey in the Snake River Canyon, Wyoming

A 5-year winter bald eagle survey was conducted along 22 km of the Snake River Canyon in northwestern Wyoming. Surveys were done on 94 days requiring 1,414 hrs and 1,888 km driving. In all, 220 (85 percent adults) bald eagles were seen. Seventy-seven percent of all eagles were perching, 15 percent were flying, 4 percent were feeding on road-killed mule deer, and 4 percent were flying low over water. Perching sites were identified as 32 percent cottonwoods, 30 percent spruce, 17 percent Douglas-fir, and 22 percent other. Eagles were somewhat clumped in distribution.     

Ecological classification and monitoring model for the Wyoming big sagebrush shrubsteppe habitat type of northeastern Wyoming

The purposes of this study were to develop a multivariate statistical model related to plant succession, to classify by seral stage, and to monitor succession in Wyoming big sagebrush shrubsteppe habitat ( Artemisia tridentata ssp. wyomingensis / Agropyron smithii–Bouteloua gracilis ) in Thunder Basin National Grassland, Wyoming. This model can be used by range and wildlife managers to evaluate management alternatives by assessing changes in plant species cover and composition within and between seral stages. Four ecological seral stages that represent early to late succession were quantitatively identified with an estimated 92% accuracy. Three key plant species provided the necessary information to define seral stages and monitor trends. Percent canopy cover and percent frequency (used to calculate index values: % canopy cover × % frequency of occurrence) of Wyoming big sagebrush ( Artemisia tridentata ssp. wyomingensis ), western wheatgrass ( Agropyron smithii ), and blue grama ( Bouteloua gracilis ) are the only field measurements required for this model.     

Additions to the vascular flora of Teton County, Wyoming

An annotated list of 125 taxa new to the flora of Teton County is presented, increasing the number of known species to 1043.     

Preliminary mammal survey of Fossil Butte National Monument, Wyoming

The mammalian community of Fossil Butte National Monument, Wyoming, consisted of at least 45 species. Snap trap sampling of the smaller species combined with sight and sign observations of the larger species formed the basis of this preliminary survey in the summers of 1974 and 1975. Snap - trapping samples (2880 trap days) yielded 44 least chipmunks and 89 deer mice. The distribution of all species was characterized by plant community occupancy. Heavy domestic livestock use of the communities nearest water has resulted in severe alteration in community structure; this has probably affected the distribution and abundance of at least some of the smaller mammals.     

Habitat and nesting biology of Mountain Plovers in Wyoming

Although previous research has considered habitat associations and breeding biology of Mountain Plovers in Wyoming at discrete sites, no study has considered these attributes at a statewide scale. We located 55 Mountain Plover nests in 6 counties across Wyoming during 2002 and 2003. Nests occurred in 2 general habitat types: grassland and desert-shrub. Mean estimated hatch date was 26 June ( n = 31) in 2002 and 21 June ( n = 24) in 2003. Mean hatch date was not related to latitude or elevation. Hatch success of nests was inferred in 2003 by the presence of eggshell fragments in the nest scrape. Eggs in 14 of 22 (64%) known-fate nests hatched. All grassland sites and 90% of desert sites were host to ungulate grazers, although prairie dogs were absent at 64% of nest sites. Nest plots had less grass coverage and reduced grass height compared with random plots. More than 50% of nests occurred on elevated plateaus. The Mountain Plover's tendency to nest on arid, elevated plateaus further substantiates claims that the bird is also a disturbed- prairie species.     

Mite parasitism of mosquitoes in central Wyoming

Parasitic larval mites including Thyasides sphagnorum were collected from mosquitoes captured in New Jersey light traps over a period of 6 yr and from landings during 1 collecting season in Natrona County, Wyoming. Overall mite prevalence on mosquitoes was 0.42% and abundance was 0.76%. Prevalence on Aedes dorsalis was significantly greater than on other host species. Comparison of light trap data and landing data suggests that parasitized mosquitoes may seek blood meals more frequently than non-parasitized mosquitoes.