West Coon Rapids, MN, United States
West Coon Rapids, MN, United States

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Verma S.K.,U.S. Department of Agriculture | Carstensen M.,463 C West Broadway | Calero-Bernal R.,U.S. Department of Agriculture | Jiang T.,University of Tennessee at Knoxville | And 2 more authors.
Parasitology Research | Year: 2016

Toxoplasma gondii infections are widespread in white-tailed deer (Odocoileus virginianus) but little is known of its prevalence in other cervids in the USA. Moose (Alces alces) is a popular large game animal, hunted for its meat and trophy antlers. Here, we report seroprevalence, isolation, and genetic characterization of T. gondii from moose from Minnesota. Antibodies against T. gondii were detected in 8 of 79 (10 %) moose tested by the modified agglutination test (MAT 1:25 or higher). The myocardium of 68 moose was bioassayed individually in mice, irrespective of serological status. T. gondii was detected in three moose (2 adults, 1 3 weeks old). The parasite from 2 adults was further propagated in cell culture. PCR-RFLP genotyping of cell culture derived tachyzoites using 10 genetic markers, SAG1, SAG2 (5′ and 3′ SAG2, and alt.SAG2), SAG3, BTUB, GRA6, c22-8, c29-2, L358, PK1, and Apico revealed two different ToxoDB PCR-RFLP genotypes (#5, designated TgMooseUS1, and #7, TgMooseUS2). The mice inoculated with myocardium of the juvenile moose developed antibodies against T. gondii, and DNA extracted from infected mouse brain was only partially characterized by PCR-RFLP genotyping, which suggests a potential new genotype. Result documented prevalence of T. gondii in moose, and its possible transplacental/transmammary transmission of T. gondii in moose. © 2015, Springer-Verlag Berlin Heidelberg (outside the USA).

Ward M.C.,7316 State Highway 371 | Staples D.F.,463 C West Broadway
Journal of Great Lakes Research | Year: 2012

Hatchery augmentation of steelhead Oncorhynchus mykiss was evaluated over 20. years in Minnesota tributaries of Lake Superior using three approaches - stocking fry or yearlings of a naturalized strain (STT), and yearlings of a domesticated strain (KAM). The STT strain was introduced over 100. years ago and became naturalized to Lake Superior and its tributaries, unlike KAM, which has not been shown to reproduce successfully in streams. We compared smolt-adult return rates to anglers and in-river traps, and production costs per adult for these three programs in the French and Knife rivers. STT smolts derived from stocked fry in the French River resulted in the highest smolt-adult return rates to traps and anglers (13.3%), and lowest cost per returning adult ($46). STT stocked as yearling smolts produced the lowest return rate (1.5%) and highest cost per returning adult ($192) for both rivers combined. KAM stocked as yearling smolts were intermediate in return rate (2.6%) and cost per adult ($90). Differences in return rates of the three strains were attributable to the extent of domestication selection, size at stocking, season of stocking, and summer lake temperatures. Smolts derived from fry-stocked STT were strongly influenced by summer lake temperatures in their first lake year. Yearling-stocked STT were influenced by size at stocking and summer lake temperatures. KAM yearlings benefitted from summer stocking at larger sizes. Based on poor survival and fiscal constraints, the STT yearling program was discontinued. Stocking programs will continue to evolve according to changing biological, financial, social, and political pressures. © 2012 Elsevier B.V.

Staples D.F.,463 C West Broadway
North American Journal of Fisheries Management | Year: 2011

Gill nets are a versatile fish sampling gear used for many species and habitats; however, their usefulness may be limited by selectivity patterns and reliance on fish movement, which can be influenced by several factors. We evaluated the effect of net length, time of day, sampling date, surface water temperature, soak time, water depth, and location on the number, length, and initial mortality of walleyes Sander vitreus caught in short-term (mean, 38.8 min; range, 10-200 min) gill nets set in Mille Lacs Lake, Minnesota. The number of walleyes caught was best described by a generalized additive model (GAM) that contained all seven covariates and explained 35% of the variation in catch. The length of walleyes caught was best described by a GAM that contained time of day, sampling date, soak time, and sampling location as covariates and explained 11% of the variation in fish length. The initial mortality of walleyes was best described by a GAM that included surface water temperature and soak time as covariates.Walleye catches were higher fromdusk to dawn than at other times, with peak catches occurring around 0500 and 2100 hours, demonstrating the diel activity patterns of walleyes. Catches also increased with surface water temperature and soak time. However, the initial mortality of walleyes also increased with surface water temperature and soak time, with the largest increase in initial mortality at soak times longer than 60 min. Investigators can use these results to assist in designing and planning short-term gill-netting efforts to maximize the catch and minimize the mortality of walleyes. © American Fisheries Society 2011.

Staples D.F.,463 C West Broadway
North American Journal of Fisheries Management | Year: 2011

Anglers sometimes use alternatives or modifications to J-shaped hooks to reduce hooking mortality in fish that are caught with live baits and then released. One such modification, the removal of barbs, has been evaluated for several fish species but has shown little promise for reducing hooking mortality; however, barbless hooks have not been evaluated for walleye Sander vitreus. We evaluated relativemortality for walleyes (228-419mmtotal length) that were caught by means of bobber fishing with leeches on barbed (n = 179 fish) or barbless (n = 209) live-bait octopus hooks or on barbed jigs (n = 193); after capture, the fish were held for 120 h in net pens. Holding mortality was a function of water temperature, cage density, bleeding level, and hook location; fish length and angler handling time did not significantly affect mortality.We combined hook location and bleeding level to create a single variable, hooking damage, which was used to replace the two variables in the initial model. This second model was similar to the first, indicating that hooking damage was correlated with mortality when controlling for the effects of water temperature and cage density.We also determined that hooking damage was correlated with hook type. For the 228-419-mm walleyes in our study, barbed jigs caused less damage than live-bait hooks and damage levels were similar between barbed and barbless live-bait hooks. Given specified levels of hooking damage, holding mortality was independent of hook type. We hypothesize that the fish in this study were too small to swallow the jigs well and thus were hooked less critically and bled less than fish that were caught with live-bait hooks. This study illustrates how gear type can affect hooking mortality based on the amount of damage caused when the fish is caught and adds to the body of literature indicating that the removal of barbs from hooks does not increase fish survival. © American Fisheries Society 2011.

Kie J.G.,Idaho State University | Matthiopoulos J.,University of St. Andrews | Fieberg J.,463 C West Broadway | Powell R.A.,North Carolina State University | And 4 more authors.
Philosophical Transactions of the Royal Society B: Biological Sciences | Year: 2010

Recent advances in animal tracking and telemetry technology have allowed the collection of location data at an ever-increasing rate and accuracy, and these advances have been accompanied by the development of new methods of data analysis for portraying space use, home ranges and utilization distributions. New statistical approaches include data-intensive techniques such as kriging and nonlinear generalized regression models for habitat use. In addition, mechanistic home-range models, derived from models of animal movement behaviour, promise to offer new insights into how home ranges emerge as the result of specific patterns of movements by individuals in response to their environment. Traditional methods such as kernel density estimators are likely to remain popular because of their ease of use. Large datasets make it possible to apply these methods over relatively short periods of time such as weeks or months, and these estimates may be analysed using mixed effects models, offering another approach to studying temporal variation in space-use patterns. Although new technologies open new avenues in ecological research, our knowledge of why animals use space in the ways we observe will only advance by researchers using these new technologies and asking new and innovative questions about the empirical patterns they observe. © 2010 The Royal Society.

Beck M.W.,University of Minnesota | Beck M.W.,U.S. Environmental Protection Agency | Tomcko C.M.,1201 E. Highway 2 | Valley R.D.,200 Warner Road | Staples D.F.,463 C West Broadway
Ecological Indicators | Year: 2014

Biological indicators that signal changes in lake condition are essential tools for guiding resource management decisions. Macrophyte-based indicators have traditionally been selected and evaluated in the context of nutrient-based stressors, although the need to evaluate indicators that are sensitive to climate stressors has been increasingly relevant. Moreover, indicators should ideally exhibit minimal sampling variation and have low natural temporal variation so there is high power to detect changes in the mean value over time. Eight macrophyte indicators were estimated in 23 Minnesota (USA) lakes using four years of repeated surveys to estimate sampling and temporal variation, response to development (phosphorus concentration) and climate stress (annual growing degree days), and power to detect significant change at various annual sampling intervals. Indicators included a macrophyte index of biotic integrity, floristic quality index, maximum depth of growth, total species richness, common species richness, mean richness, and frequency occurrence of rooted species and Chara sp. Overall, regression and smoothed additive models indicated significant relationships of indicators to total lake phosphorus and mean annual growing degree days. The macrophyte index of biotic integrity, floristic quality index, and the frequency rooted species had minimal sampling variation in this study, were responsive to development or climate stress, and had low annual variation (coefficients of variation 0.08, 0.10, and 0.19, respectively) resulting in high to moderate power (>50%) for detecting significant change over a 20 year period. Results from these analyses will facilitate the use of precise and powerful indicators that respond to stressors that are of concern for the management of freshwater glacial lakes. © 2014 Elsevier Ltd.

Street G.M.,Mississippi State University | Fieberg J.,University of Minnesota | Rodgers A.R.,Ontario Ministry of Natural Resources | Carstensen M.,463 C West Broadway | And 4 more authors.
Landscape Ecology | Year: 2016

Context: Animals selectively use landscapes to meet their energetic needs, and trade-offs in habitat use may depend on availability and environmental conditions. For example, habitat selection at high temperatures may favor thermal cover at the cost of reduced foraging efficiency under consistently warm conditions. Objective: Our objective was to examine habitat selection and space use in distinct populations of moose (Alces alces). Hypothesizing that endotherm fitness is constrained by heat dissipation efficiency, we predicted that southerly populations would exhibit greater selection for thermal cover and reduced selection for foraging habitat. Methods: We estimated individual step selection functions with shrinkage for 134 adult female moose in Minnesota, USA, and 64 in Ontario, Canada, to assess habitat selection with variation in temperature, time of day, and habitat availability. We averaged model coefficients within each site to quantify selection strength for habitats differing in forage availability and thermal cover. Results: Moose in Ontario favored deciduous and mixedwood forest, indicating selection for foraging habitat across both diel and temperature. Habitat selection patterns of moose in Minnesota were more dynamic and indicated time- and temperature-dependent trade-offs between use of foraging habitat and thermal cover. Conclusions: We detected a scale-dependent functional response in habitat selection driven by the trade-off between selection for foraging habitat and thermal cover. Landscape composition and internal state interact to produce complex patterns of space use, and animals exposed to increasingly high temperatures may mitigate fitness losses from reduced foraging efficiency by increasing selection for foraging habitat in sub-prime foraging landscapes. © 2016 Springer Science+Business Media Dordrecht

PubMed | Cleveland Metroparks Zoo, University of Tennessee at Knoxville, U.S. Department of Agriculture and 463 C West Broadway
Type: Journal Article | Journal: Veterinary parasitology | Year: 2014

The prevalence of Toxoplasma gondii in white tailed deer (WTD) in the USA is high but little is known of the epidemiology of toxoplasmosis in this host. In the present study, we compared T. gondii seroprevalence from 749 WTD collected in 2012 and 2013 from a Metropolitan Park in Ohio and 487 WTD deer shot in Minnesota during 2008, 2009, and 2010. Serum samples were tested for antibodies to T. gondii by the modified agglutination test (cut-off titer, 25). Additionally myocardial samples from 123 seropositive WTD from Ohio were digested in pepsin and the digests were bioassayed for the isolation of T. gondii. Furthermore, to estimate transplacental rate of transmission, brains from 155 fetuses (included twins) from 148 deer from Minnesota were bioassayed in mice for the isolation of viable T. gondii. Seroprevalence of T. gondii varied with the year of collection, geography, and the age of deer. Of the Ohio deer sampled in 2012 and 2013 seroprevalences for the two years were similar (73.4% and 75.7%, respectively); remarkably 150 (66.1%) of 227 deer of <1 year of age were seropositive. Of the Minnesota deer, seroprevalence was lowest for the year 2008 (14.8%, 26/175) versus 2009 (27.7%, 59/213), and 2010 (25.2%, 25/99), thought to be related to environmental temperatures. Viable T. gondii was isolated in mice from the myocardium of four WTD from Ohio, and brain of one WTD fetus from Minnesota. Tachyzoites from infected mouse tissues were further propagated in cell culture. The DNA isolated from culture-derived tachyzoites of these five T. gondii isolates was characterized using 11 PCR-RFLP markers (SAG1, 5- and 3-SAG2, alt.SAG2, SAG3, BTUB, GRA6, c22-8, c29-2, L358, PK1 and Apico). Four genotypes were found, including ToxoDB genotype no. 1 (Type II), no. 2 (Type III), no. 3 (Type II variant) and no. 146. Results indicate fluctuating seroprevalence, probably related to weather and warrant further epidemiological studies.

PubMed | University of Minnesota and 463 C West Broadway
Type: Journal Article | Journal: Ecological applications : a publication of the Ecological Society of America | Year: 2016

Age at maturity (AAM) is a key life history trait that provides insight into ecology, evolution, and population dynamics. However, maturity data can be costly to collect or may not be available. Life history theory suggests that growth is biphasic for many organisms, with a change-point in growth occurring at maturity. If so, then it should be possible to use a biphasic growth model to estimate AAM from growth data. To test this prediction, we used the Lester biphasic growth model in a likelihood profiling framework to estimate AAM from length at age data. We fit our model to simulated growth trajectories to determine minimum data requirements (in terms of sample size, precision in length at age, and the cost to somatic growth of maturity) for accurate AAM estimates. We then applied our method to a large walleye Sander vitreus data set and show that our AAM estimates are in close agreement with conventional estimates when our model fits well. Finally, we highlight the potential of our method by applying it to length at age data for a variety of ectotherms. Our method shows promise as a tool for estimating AAM and other life history traits from contemporary and historical samples.

PubMed | U.S. Department of Agriculture and 463 C West Broadway
Type: Journal Article | Journal: Veterinary parasitology | Year: 2014

Neospora caninum is a common cause of abortion in cattle worldwide. Canids, including the dog and the dingo (Canis familiaris), the coyote (Canis latrans), and the gray wolf (Canis lupus) are its definitive hosts that can excrete environmentally resistant oocysts in the environment, but also can act as intermediate hosts, harboring tissue stages of the parasite. In an attempt to isolate viable N. caninum from tissues of naturally infected wolves, brain and heart tissue from 109 wolves from Minnesota were bioassayed in mice. Viable N. caninum (NcWolfMn1, NcWolfMn2) was isolated from the brains of two wolves by bioassays in interferon gamma gene knockout mice. DNA obtained from culture-derived N. caninum tachyzoites of the two isolates were analyzed by N. caninum-specific Nc5 polymerase chain reaction and confirmed diagnosis. This is the first report of isolation of N. caninum from tissues of any wild canid host.

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