Hardy R.S.,885 W. Kathleen Ave. |
Stephenson S.M.,British Columbia Ministry of forests |
Neufeld M.D.,British Columbia Ministry of forests |
Young S.P.,Kootenai Tribe of Idaho
Hydrobiologia | Year: 2015
Burbot Lota lota maculosa numbers in Kootenay Lake and Kootenai River of British Columbia, Idaho, and Montana have diminished due to habitat changes from the construction of Libby Dam. Recent implementation of a conservation strategy included aquaculture to supplement the population using a donor stock from a self-sustaining lake population within the watershed. Evaluation of release strategies using telemetry and mark recapture through hoop netting suggests lake-origin Burbot have adapted to the Kootenai system and selected riverine over lacustrine habitat. Previous telemetry work identified good survival and dispersal of released Burbot, and vast dispersal distance and lacustrine use. However, our analysis of a broader telemetry dataset indicated that only 24% of age 1–4 Burbot were detected in the lake. Recapture hoop net data indicated that Burbot residing in the river have growth and survival rates comparable to the historical population. Spawning of hatchery origin fish was detected at historical riverine spawning locations. Other than later spawn timing, our evaluations suggest lake-origin fish are mimicking movement and habitat use of the historical riverine population. This study, in combination with others, provides evidence that Burbot progeny from lacustrine brood stock can successfully survive, grow, disperse, and spawn in a riverine environment. © 2015 Springer International Publishing Switzerland
Watkins C.J.,University of Idaho |
Ross T.J.,885 W. Kathleen Ave. |
Hardy R.S.,885 W. Kathleen Ave. |
Quist M.C.,University of Idaho
Western North American Naturalist | Year: 2015
The mountain whitefish (Prosopium williamsoni) is a widely distributed salmonid in western North America that has decreased in abundance over portions of its distribution due to anthropogenic disturbances. In this investigation, we examined precision of age estimates derived from scales, pectoral fin rays, and sagittal otoliths from 167 mountain whitefish. Otoliths and pectoral fin rays were mounted in epoxy and cross-sectioned before examination. Scales were pressed onto acetate slides and resulting impressions were examined. Between-reader precision (i.e., between 2 readers), between-reader variability, and reader confidence ratings were compared among hard structures. Coefficient of variation (CV) in age estimates was lowest and percentage of exact agreement (PA-0) was highest for scales (CV = 5.9; PA-0 = 70%) compared to pectoral fin rays (CV =11.0; PA-0 = 58%) and otoliths (CV = 12.3; PA-0 = 55%). Median confidence ratings were significantly different (P ≤ 0.05) among all structures, with scales having the highest median confidence. Reader confidence decreased with fish age for scales and pectoral fin rays, but reader confidence increased with fish age for otoliths. In general, age estimates were more precise and reader confidence was higher for scales compared to pectoral fin rays and otoliths. This research will help fisheries biologists in selecting the most appropriate hard structure to use for future age and growth studies on mountain whitefish. In turn, selection of the most precise hard structure will lead to better estimates of dynamic rate functions. © 2015 Western North American Naturalist.
Caldwell T.J.,University of Idaho |
Caldwell T.J.,University of Nevada, Reno |
Wilhelm F.M.,University of Idaho |
Dux A.,885 W. Kathleen Ave
Canadian Journal of Fisheries and Aquatic Sciences | Year: 2016
Establishment of non-native species can alter native species populations and restructure lake food webs through complex tropic interactions such as intraguild predation or classic trophic cascades. Although the freshwater shrimp Mysis diluviana is well known for its ability to impact both primary and secondary productivity through omnivorous feeding in aquatic ecosystems in which it has been introduced, empirical evidence of mysid consumption of zooplankton prey and associated impacts on cladoceran communities from the same lake is uncommon. Furthermore, recent literature has suggested that mysids may impact other zooplankton populations outside of cladocerans. To test the hypothesis that introduced mysids negatively affect the seasonal abundance of cladocerans in Lake Pend Oreille, a large and deep (348 km2, max. depth: 352 m) lake in Idaho, USA, we quantified the seasonal diet and consumption rates of mysids and compared them with cladoceran production rates. During isothermal conditions, mysids opportunistically fed on copepods, diatoms, and rotifers. However, during stratification, mysids strongly selected cladocerans. In addition, during isothermal conditions, mysids consumed 100% of cladoceran production and selected reproductive-sized individuals. We interpret this to show that mysids regulate the production of cladocerans when the lake is not stratified. The suppression of cladocerans in the spring coincides with the appearance of kokanee (Oncorhynchus nerka) fry whose growth and survival may be negatively affected by the lack of abundant cladocerans, a preferred prey. This suggests a possible cascading effect to higher trophic levels. © 2016, National Research Council of Canada. All Rights Reserved.
Wasserman T.N.,Northern Arizona University |
Cushman S.A.,U.S. Department of Agriculture |
Wallin D.O.,Western Washington University |
Hayden J.,885 W. Kathleen Ave.
USDA Forest Service - Research Paper RMRS-RP | Year: 2012
We used bivariate scaling and logistic regression to investigate multiple-scale habitat selection by American marten (Martes americana). Bivariate scaling reveals dramatic differences in the apparent nature and strength of relationships between marten occupancy and a number of habitat variables across a range of spatial scales. These differences include reversals in the direction of an observed association from positive to negative and frequent dramatic changes in the apparent importance of a habitat variable as a predictor of marten occurrence. Logistic regression on the optimally scaled input variables suggests that at the scale of home ranges, marten select landscapes with high average canopy closure and low fragmentation. Within these low fragmented landscapes, marten select foraging habitat at a fine scale within late-seral, middle-elevation mesic forests. In northern Idaho, optimum American marten habitat, therefore, consists of landscapes with low road density, low density of non-forest patches with high canopy closure, and large areas of middle-elevation, late successional mesic forest. Comparison of current landscape conditions to those expected under the historic range of variability indicates that road building and timber harvest in the past century may have substantially reduced the amount of suitable marten habitat in northern Idaho. Our results are generally consistent with previous research in the Rocky Mountains, with additional insights related to the relative importance, functional form, and scale at which each habitat variable has the largest influence on marten occurrence.
Smith C.D.,University of Idaho |
Quist M.C.,U.S. Geological Survey |
Hardy R.S.,885 W. Kathleen Ave
Journal of Fish and Wildlife Management | Year: 2015
Research comparing different sampling techniques helps improve the efficiency and efficacy of sampling efforts. We compared the effectiveness of three sampling techniques (small-mesh hoop nets, benthic trawls, boat-mounted electrofishing) for 30 species in the Green (WY, USA) and Kootenai (ID, USA) rivers by estimating conditional detection probabilities (probability of detecting a species given its presence at a site). Electrofishing had the highest detection probabilities (generally greater than 0.60) for most species (88%), but hoop nets also had high detectability for several taxa (e.g., adult burbot Lota lota, juvenile northern pikeminnow Ptychocheilus oregonensis). Benthic trawls had low detection probabilities (<0.05) for most taxa (84%). Gear-specific effects were present for most species indicating large differences in gear effectiveness among techniques. In addition to gear effects, habitat characteristics also influenced detectability of fishes. Most species-specific habitat relationships were idiosyncratic and reflected the ecology of the species. Overall findings of our study indicate that boat-mounted electrofishing and hoop nets are the most effective techniques for sampling fish assemblages in large, coldwater rivers. © Citation of the source, as given above, is requested.