Depew D.C.,Queen's University |
Depew D.C.,National Water Research Institute |
Burgess N.M.,Environment Canada |
Anderson M.R.,Canadian Department of Fisheries and Oceans |
And 13 more authors.
Canadian Journal of Fisheries and Aquatic Sciences | Year: 2013
Fish mercury (Hg) concentrations have been measured over the last 30-40 years in all regions of Canada as part of various monitoring and research programs. Despite this large amount of data, only regional assessments of fish Hg trends and patterns have previously been attempted. The objective of this study was to assemble available freshwater fish Hg concentration data from all provinces and territories and identify national patterns. The Canadian Fish Mercury Database includes over 330 000 records representing 104 species of freshwater fish collected from over 5000 locations across Canada between 1967 and 2010. Analysis of the 28 most frequently occurring species (>1000 records) showed that the majority of variation in Hg concentrations (when normalized to a standard size) was accounted for by geographic location. Median Hg concentrations increased with trophic level (r = 0.40, p < 0.05), with the highest Hg concentrations found in piscivorous species such as walleye (Sander vitreus), northern pike (Esox lucius), and lake trout (Salvelinus namaycush). The Canadian Fish Mercury Database provides the most comprehensive summary of fish Hg measurements in Canada, and the results indicate that several regionally observed trends in fish Hg concentrations (e.g., Hg biomagnification and geographic variation) are observed at a national scale. Implications for the effective assessment of changes in fish Hg concentrations in relation to changes in Hg emission regulations are discussed.
Pilfold N.W.,University of Alberta |
Hedman D.,Manitoba Conservation and Water Stewardship |
Stirling I.,University of Alberta |
Stirling I.,Environment Canada |
And 3 more authors.
Physiological and Biochemical Zoology | Year: 2016
Polar bears (Ursus maritimus) have adapted to an annual cyclic regime of feeding and fasting, which is extreme in seasonal sea ice regions of the Arctic. As a consequence of climate change, sea ice breakup has become earlier and the duration of the openwater period through which polar bears must rely on fat reserves has increased. To date, there is limited empirical data with which to evaluate the potential energetic capacity of polar bears to withstand longer fasts.Wemeasured the incoming and outgoingmass of inactive polar bears (np142) that were temporarily detained by Manitoba Conservation and Water Stewardship during the open-water period near the town of Churchill, Manitoba, Canada, in 2009–2014. Polar bears were given access to water but not food and held for a median length of 17 d. Median mass loss rates were 1.0 kg/d, while median mass-specific loss rates were 0.5%/d, similar to other species with high adiposity and prolonged fasting capacities. Mass loss by unfed captive adult males was identical to that lost by free-ranging individuals, suggesting that terrestrial feeding contributes little to offsetmass loss. The inferred metabolic rate was comparable to a basal mammalian rate, suggesting that while on land, polar bears can maintain a depressed metabolic rate to conserve energy. Finally, we estimated time to starvation for subadults and adult males for the on-land period. Results suggest that at 180 d of fasting, 56%–63% of subadults and 18%–24% of adult males in this study would die of starvation Results corroborate previous assessments on the limits of polar bear capacity to withstand lengthening ice-free seasons and emphasize the greater sensitivity of subadults to changes in sea ice phenology. © 2016 by The University of Chicago. All rights reserved.
Donald D.B.,Environment Canada |
Parker B.R.,Manitoba Conservation and Water Stewardship |
Davies J.-M.,Saskatchewan Water Security Agency and 101 |
Leavitt P.R.,University of Regina
Journal of Great Lakes Research | Year: 2015
Lake Winnipeg, Manitoba, has been subjected to significant increases in nutrient loading over the last few decades, and consequently has experienced significant and widespread algal blooms. The objective of our study was to identify sources of nutrients in the Lake Winnipeg basin, and quantify their removal (sequestration) into 28 of the largest lakes and reservoirs located in the Saskatchewan, Dauphin, Red, and Winnipeg river sub-basins, thus preventing their transport downstream to Lake Winnipeg. Discharges were determined daily, and nutrient parameter concentrations determined once or twice each month upstream and downstream from each of the lakes and reservoirs for three years. Concentrations of P and N in source waters of the Lake Winnipeg basin varied substantially, with the lowest concentrations occurring in pristine headwaters of the Saskatchewan River (mean TP. =. 14. μg/L; mean TN. =. 217. μg/L) and some of the highest concentrations occurring in small streams that originated within agricultural landscapes in the headwaters of the Dauphin River sub-basin (mean TP. =. 133. μg/L; mean TN. =. 1313. μg/L). Twelve reservoirs in the Saskatchewan River sub-basin collectively sequestered 92% of the TP inputs and 68% of the TN inputs to the sub-basin. In P-rich lakes, relatively more N was sequestered than P compared with nutrient impoverished lakes. A total 13,215. t/yr TP was discharged into Lake Winnipeg while 8234. t. TP/yr, was sequestered into the lakes and reservoirs. The Red River sub-basin was the principal source of nutrients to Lake Winnipeg and should be the focus of nutrient management in the Lake Winnipeg basin. © 2015 International Association for Great Lakes Research..
Clouthier S.C.,University of Winnipeg |
Vanwalleghem E.,University of Winnipeg |
Vanwalleghem E.,University of Manitoba |
Copeland S.,University of Winnipeg |
And 4 more authors.
Diseases of Aquatic Organisms | Year: 2013
A newly discovered virus, Namao virus, associated with morbidity and mortality, was detected among juvenile lake sturgeon Acipenser fulvescens being propagated by a conservation stocking program for this endangered species in Manitoba, Canada. The outbreaks resulted in cumulative mortalities of 62 to 99.6% among progeny of wild Winnipeg River or Nelson River lake sturgeon and occurred at 2 geographically separate facilities. Namao virus was detected in almost 94% of the moribund or dead lake sturgeon according to a conventional polymerase chain reaction (cPCR) test that is based upon amplification of a 219 bp fragment of the virus major capsid protein (MCP). The virus itself was large (242 to 282 nm) and icosahedral-shaped with 2 capsids and a condensed bar-shaped core. It was found in virus factories within the host cell cytoplasm and displayed a tropism for the integument. Namao virus caused cellular changes characterized by enlarged eosinophilic epithelial cells in the gills and skin. Samples suspected of containing Namao virus did not have cytopathic effects on primary lake sturgeon or established white sturgeon cell lines. However, viral nucleic acid was detected in the former after prolonged incubation periods. Using primers designed from conserved regions of the MCP from NCLDVs, an estimated 95 to 96% of the Namao virus MCP open reading frame was captured. Phylogenetic analysis using the MCP of Namao virus and 27 other NCLDVs suggested that Namao virus and white sturgeon iridovirus share a common evolutionary past and might be members of the family Mimiviridae or a new, as yet unrecognized, virus family. © Inter-Research and Fisheries and Oceans Canada 2013.
PubMed | Manitoba Conservation and Water Stewardship, University of Manitoba and Trent University
Type: Journal Article | Journal: Royal Society open science | Year: 2016
Understanding the evolutionary history of contemporary animal groups is essential for conservation and management of endangered species like caribou (Rangifer tarandus). In central Canada, the ranges of two caribou subspecies (barren-ground/woodland caribou) and two woodland caribou ecotypes (boreal/eastern migratory) overlap. Our objectives were to reconstruct the evolutionary history of the eastern migratory ecotype and to assess the potential role of introgression in ecotype evolution. STRUCTURE analyses identified five higher order groups (i.e. three boreal caribou populations, eastern migratory ecotype and barren-ground). The evolutionary history of the eastern migratory ecotype was best explained by an early genetic introgression from barren-ground into a woodland caribou lineage during the Late Pleistocene and subsequent divergence of the eastern migratory ecotype during the Holocene. These results are consistent with the retreat of the Laurentide ice sheet and the colonization of the Hudson Bay coastal areas subsequent to the establishment of forest tundra vegetation approximately 7000 years ago. This historical reconstruction of the eastern migratory ecotype further supports its current classification as a conservation unit, specifically a Designatable Unit, under Canadas Species at Risk Act. These findings have implications for other sub-specific contact zones for caribou and other North American species in conservation unit delineation.
Reichelt R.,Manitoba Conservation and Water Stewardship
Geoscience Canada | Year: 2014
Professional geoscientists, including those practicing environmental geo-science, have definite and definable legal and ethical responsibilities. These obligations apply to environmental geoscientists working as consultants, academics, regulators or environmental managers. Environmental geoscientists are obliged to be aware of and obey all federal, provincial and municipal laws and regulations applying to professional geoscientists. As well as the provincial engineering and geoscience acts, a variety of additional guidelines and professional standards apply to the professional geoscientist. These include criminal, labour, and business law as well as environmental acts and regulations. Governments, professional associations and private standards agencies, such as the Canadian Standards Association and the American Society for Testing and Materials, have also issued relevant guidelines and standards. © 2014 GAC/AGC®
Legault J.M.,Geotech Ltd. |
Toop D.,Manitoba Conservation and Water Stewardship |
Oldenborger G.A.,Geological Survey of Canada |
Plastow G.,Geotech Ltd. |
And 3 more authors.
28th Symposium on the Application of Geophysics to Engineering and Environmental Problems 2015, SAGEEP 2015 | Year: 2015
VTEM helicopter time-domain EM survey results over the Brandon Channel and Assiniboine Delta aquifers, near Brandon, Manitoba, have been studied using unconstrained layered earth modeling. The resistive sand and gravel layers are distinguished from the more conductive shale basement and reveal localized thickening from blind gravel channels cut into its floor. They further distinguish a lower aquifer separated by a conductive clay layer from shallow sands of the Assiniboine Alluvial aquifer and the Assiniboine Delta Aquifer. The Brandon Channel aquifer is delineated, to the northwest and east of the city where it splits into a main south channel and smaller north channel. The western extent of Assiniboine Alluvial aquifer is defined and evidence for the Pierson Valley aquifer extending west from Brandon is also indicated.
Beshada E.,Manitoba Conservation and Water Stewardship |
Zhang Q.,University of Manitoba |
Boris R.,Manitoba Hydro
Canadian Biosystems Engineering / Le Genie des biosystems au Canada | Year: 2014
An experimental study was conducted to compare two localized heating methods, namely heat pads and heat lamps, in a commercial swine farrowing facility. Two farrowing rooms each with 44 crates were instrumented for monitoring room environmental conditions (temperature and relative humidity) and energy consumption. One room was equipped with 175W (per crate) heat lamps and the other room with 65W (per crate) heat pads. The piglet mortality and weight gain were recorded. The air temperature in the two rooms was maintained at the same level using environmental controllers (set at the same setpoint). However, the relative humidity in the lamp room was found to be lower than that in the heat pad room probably due to more ventilation required to remove more sensible heat produced by the lamps. There were no significant differences in the mortality rate and weight gain between heat pads and heat lamps. The daily energy consumption by heat pads was 2.9 kWh less than that by heat lamps per crate. This represents a 73% saving of energy required for localized heating.
Deb A.K.,Manitoba Conservation and Water Stewardship
Journal of Ethnobiology | Year: 2015
Caste-based Hindu coastal fishers of Bangladesh have developed their Traditional Ecological Knowledge (TEK), environment and resource friendly practices, and worldviews through years of social learning, and interaction with their immediate ecosystem. This article is based on 21-month long participatory field research with the fishers of Thakurtala fishing village, Moheskhali Island, Cox'sbazar district, located along the Bay of Bengal. Eight important categories of fishers' TEK systems are examined: water color, wind direction and current, lunar periodicity, sediment and topography, celestial navigation, birds and animals, mangroves, and fishing sites. Fishers make their decisions about fishing at a certain site using practical heuristic rules. The sequence of learning and transmission of TEK at different age strata is examined. Policy makers would benefit from TEK of the experienced coastal fishers. © 2015 Society of Ethnobiology.
Nitrogen mineralization in beef- and pig-manure-amended soils measured using anion resin method [Évaluation de la minéralisation de l’azote dans les sols enrichis avec du fumier de bovins et de porcs par la méthode de la résine échangeuse d’anions]
Ige D.V.,Manitoba Conservation and Water Stewardship |
Sayem S.M.,University of Manitoba |
Akinremi O.O.,University of Manitoba
Canadian Journal of Soil Science | Year: 2015
A major challenge facing the widespread use of manure is the uncertainty about its fertilizer equivalence. This study was carried out to determine the fertilizer equivalence of locally available manures in two soils in Manitoba. A randomized complete block design was adopted with six treatments [nitrogen fertilizer, a liquid swine manure (LSM), three solid beef manures (SBM) and a control] and four replicates. Each treatment was applied to a cylindrical soil column installed at the site at the rate of 100 kg ha−1 of “available N”, and leached NO3-N was captured by resin bags at the bottom of the cylinder. The soils and resin bags removed from the cylinders were sampled at 0, 1, 2, 4, 6, 8, 10, 14, and 18 wk following treatment application. Ammonium nitrogen in the amendments was nitrified within the first 2 to 3 wk with significant build-up of NO3-N in the soil above the control (P<0.05). The greatest available N was in the fertilizer treatment, followed by the LSM and the smallest was in the SBM. The available N in the three SBM was statistically similar (P>0.05). Approximately 50% of the inorganic N in LSM was available during the growing season, while 68 to 100% of SBM inorganic N was available. Between 4 and 25% of the organic N in the three SBM was mineralized during the growing season. High soil moisture hindered N mineralization and enhanced N loss in the clay soil. LSM has the greatest fertilizer equivalence, with a mean of 65 to 68%, of the four manure types used. The fertilizer equivalence of the three SBM ranged between 42 and 59% and was influenced by the manure C:N ratio and the soil environmental conditions. Our study suggests the need to revise the assumptions regarding manure N availability by considering soil environmental factors in the estimation of available N. © 2015, Agricultural Institute of Canada. All rights reserved.