North South Consultants Inc.

Winnipeg, Canada

North South Consultants Inc.

Winnipeg, Canada
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McDougall C.A.,North South Consultants Inc. | McDougall C.A.,University of Manitoba | Welsh A.B.,West Virginia University | Gosselin T.,Otterburn Park | And 2 more authors.
PLoS ONE | Year: 2017

Many hydroelectric dams have been in place for 50 - >100 years, which for most fish species means that enough generations have passed for fragmentation induced divergence to have accumulated. However, for long-lived species such as Lake Sturgeon, Acipenser fulvescens, it should be possible to discriminate between historical population structuring and contemporary gene flow and improve the broader understanding of anthropogenic influence. On the Winnipeg River, Manitoba, two hypotheses were tested: 1) Measureable quantities of former reservoir dwelling Lake Sturgeon now reside downstream of the Slave Falls Generating Station, and 2) genetically differentiated populations of Lake Sturgeon occur upstream and downstream, a result of historical structuring. Genetic methods based on ten microsatellite markers were employed, and simulations were conducted to provide context. With regards to contemporary upstream to downstream contributions, the inclusion of length-at-age data proved informative. Both pairwise relatedness and Bayesian clustering analysis substantiated that fast-growing outliers, apparently entrained after residing in the upstream reservoir for several years, accounted for ∼15% of the Lake Sturgeon 525-750 mm fork length captured downstream. With regards to historical structuring, upstream and downstream populations were found to be differentiated (FST = 0.011, and 0.013-0.014 when fast-growing outliers were excluded), and heterozygosity metrics were higher for downstream versus upstream juveniles. Historical asymmetric (downstream) gene flow in the vicinity of the generating station was the most logical explanation for the observed genetic structuring. In this section of the Winnipeg River, construction of a major dam does not appear to have fragmented a previously panmictic Lake Sturgeon population, but alterations to habitat may be influencing upstream to downstream contributions in unexpected ways. © 2017 McDougall et al.This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Clayden M.G.,University of New Brunswick | Kidd K.A.,University of New Brunswick | Wyn B.,North South Consultants Incorporated | Kirk J.L.,Environment Canada | And 2 more authors.
Environmental Science and Technology | Year: 2013

Mercury (Hg) contamination in aquatic systems remains a global concern because the organic form, methyl Hg (MeHg), can biomagnify to harmful concentrations in fish, fish-eating wildlife, and humans. Food web transfer of MeHg has been explored using models of log MeHg versus relative trophic position (nitrogen isotopes, δ15N), but regression slopes vary across systems for unknown reasons. In this study, MeHg biomagnification was determined for 11 lake food webs in Kejimkujik National Park, Nova Scotia, Canada, and compared to physical and chemical lake characteristics using principal component and multiple regression analyses. MeHg biomagnification (regression slopes of log MeHg versus baseline-adjusted δ15N for fishes and invertebrates) varied significantly across lakes and was higher in systems with lower aqueous nutrient/MeHg/chloride scores. This is one of the largest, consistent data sets available on MeHg biomagnification through temperate lake food webs and the first study to use a principal component and multiple regression approach to understand how lake chemical and physical characteristics interact to affect biomagnification among systems. Overall, our results show that the magnitude of MeHg biomagnification through lake food webs is related to the chemical and physical characteristics of the systems, but the underlying mechanisms warrant further investigation. © 2013 American Chemical Society.

Bajzak C.E.,Maurice Lamontagne Institute | Bernhardt W.,North South Consultants Inc. | Mosnier A.,Maurice Lamontagne Institute | Hammill M.O.,Maurice Lamontagne Institute | And 2 more authors.
Polar Biology | Year: 2013

Over the last few decades, the period of ice cover in Hudson Bay has decreased, owing to climate warming, with breakup occurring approximately 3 weeks earlier than it did 30 years ago. The trend towards lengthening of the open water season has led to speculation that ringed seal numbers would decline, but then harbour seals might become numerous enough to replace ringed seals in the diet of polar bears. The movement patterns of 18 harbour seals equipped with satellite-linked transmitters in the Churchill River estuary (western Hudson Bay) were examined, as well as the dive behaviour of 11 of these seals. During the ice-free period, seals followed a general central place-foraging strategy, making repeated trips between their haul-out site in the Churchill River estuary and nearshore areas (<20 km) near the river mouth and estuary. Seal behaviour changed significantly as ice started to form along the coast of western Hudson Bay: animals remained significantly farther from the Churchill River haul-out site and from the coast and performed longer and deeper dives. However, throughout the entire tracking period, whether ice was present or not, all animals restricted their movements to a narrow band of shallow coastal waters (<50 m depth) along a 600-km stretch of the western Hudson Bay coastline, centred on the Churchill River estuary haul-out site. This natural self-limitation to nearshore shallow waters could restrict the potential for the population to increase in size and replace ringed seals as a primary energy resource for polar bears. © 2012 Springer-Verlag Berlin Heidelberg.

Wyn B.,University of New Brunswick | Wyn B.,North South Consultants Inc. | Kidd K.A.,University of New Brunswick | Burgess N.M.,Environment Canada | And 2 more authors.
Environmental Science and Technology | Year: 2010

In the mid-1990s, yellow perch (Perca flavescens) and common loons (Gavia immer) from Kejimkujik National Park and National Historic Site (KNPNHS), Nova Scotia, Canada, had among the highest mercury (Hg) concentrations across North America. In 2006 and 2007, we re-examined 16 lakes to determine whether there have been changes in Hg in the loon's preferred prey, yellow perch. Total Hg concentrations were measured in up to nine perch in each of three size classes (5-10 cm, 10-15 cm, and 15-20 cm) consumed by loons. Between 1996/97 and 2006/07, polynomial regressions indicated that Hg in yellow perch increased an average of 29% in ten lakes, decreased an average of 21% in three, and were unchanged in the remaining three lakes. In 2006/07, perch in 75% of the study lakes had Hg concentrations (standardized to 12-cm fish length) equal to or above the concentration (0.21 μg·g-1ww) associated with a 50% reduction in maximum productivity of loons, compared with only 56% of these lakes in 1996/97. Mercury contamination currently poses a greater threat to loon health than a decade ago, and further reductions in anthropogenic emissions should be considered to reduce its impacts on ecosystem health. © 2010 American Chemical Society.

Genz J.,University of West Georgia | Mcdougall C.A.,North South Consultants Inc. | Burnett D.,North South Consultants Inc. | Burnett D.,University of Manitoba | And 3 more authors.
Journal of Applied Ichthyology | Year: 2014

This research assessed the endocrine and physiological effects of Ovaprim™ and synthetic homologous sturgeon gonadotrophic releasing hormone (GnRH) on spawning male and female adult lake sturgeon, Acipenser fulvescens (Rafinesque, 1817). Wild-caught adults were administered Ovaprim, GnRH, or Ringers solution (control), and serial blood samples were collected for up to 27 days following capture and hormone administration. Circulating cortisol levels appeared to increase following administration of both hormonal treatments. However, circulating cortisol was higher and plasma pH lower at capture than at any other time for all treatments, indicating that capture and transport stress were the largest disrupting factors, more so than the effects of induced spawning. Plasma concentrations of estradiol and testosterone in both sexes were similar to previously reported values. In all treatments the circulating estradiol and testosterone never significantly exceeded the values at capture prior to endocrine manipulation of the reproductive axis. Similarly, testosterone in males and estradiol in females in the muscle tissue were consistently at the same or lower concentrations than at capture. The apparent survival of all of the study animals following return to their native river indicated that the stress effects from capture and induced spawning were not severe. In concert, our results suggest that hormonal injections can be used to aid in gamete collection from wild A. fulvescens, without negative effects on long-term broodstock survival. Hatching success, larval survival to the juvenile stage, egg diameter, and concentrations of protein, triglyceride, and glucose in the egg, sperm, and ovarian fluid (but not seminal plasma), were the same or greater in GnRH-treated fish than gametes from the Ovaprim-treated group, suggesting that utilization of GnRH may be preferable to other common methods of spawning induction. © 2014 Blackwell Verlag GmbH.

Barth C.C.,North South Consultants Inc. | Anderson W.G.,University of Manitoba | Peake S.J.,University of New Brunswick | Nelson P.,North South Consultants Inc.
Journal of Applied Ichthyology | Year: 2013

Summary: The lake sturgeon, Acipenser fulvescens, is a threatened species across most of its range. To understand any potential shifts in diet across season or habitat, stomach contents were examined from juvenile lake sturgeon caught in the Winnipeg River, Manitoba, Canada. This information will aid in assessment of environmental impacts and conservation initiatives for this threatened species. From 2006 to 2008 gut contents were collected from juvenile lake sturgeon using a non-lethal gastric lavage methodology. Juvenile lake sturgeon were sampled from four discrete deep water habitat types (13.7-27.4 m depths), during the months of May, June, July and October. In total, 13 066 prey items belonging to 14 prey groups were collected from 345 juvenile lake sturgeon (251-835 mm TL). Overall, juvenile lake sturgeon consumed a low diversity of organisms; insect larvae from three invertebrate orders, Trichoptera, Diptera and Ephemeroptera, accounted for 97.4% of the total numeric abundance of prey items recovered. A relationship between size of juvenile lake sturgeon and prey quantity or type was not observed. Diet of juvenile lake sturgeon varied in relation to season, with Diptera (77.6%) being the most abundant prey in May, Trichoptera the most abundant in June (n = 3,056, 60.4%) and July (n = 2,055, 52.6%). During October, 96% of stomachs examined were empty. In terms of habitat type, the standardized abundance of invertebrate prey items was highest in deep water habitats characterized by medium water velocity (depths > 13.7 m) and coarse substrate (particle sizes > 0.063 mm) in May and June when compared to deep water habitats characterized by low water velocity (<0.2 m.s-1) and fine substrate (particle sizes < 0.063 mm). However, in July, the opposite was observed and prey abundance in juvenile lake sturgeon stomachs decreased with increasing particle size. Results suggest a high degree of dietary overlap among juvenile lake sturgeon from multiple size/age classes occupying deep-water habitats of the Winnipeg River. © 2013 Blackwell Verlag GmbH.

Brandt C.,University of Manitoba | Brandt C.,North South Consultants Inc. | Burnett D.C.,University of Manitoba | Burnett D.C.,North South Consultants Inc. | And 3 more authors.
Chemosphere | Year: 2015

Chlorpyrifos is a widely used organophosphate pesticide that has previously been shown to enter waterways in biologically relevant concentrations and has the potential to disrupt both thyroid hormone and sex steroid biosynthesis in vertebrates. Because gonadal maturation and larval development in Lake Sturgeon, Acipenser fulvescens, potentially coincide with the application of chlorpyrifos we examined the effects of chlorpyrifos on both thyroid follicular development in larval Lake Sturgeon, and sex hormone synthesis in adult Lake Sturgeon. For the first time, the present study reports steroidogenesis from testicular and ovarian tissue in Lake Sturgeon using an established in vitro bioassay. Furthermore, incubating gonad tissue with 5, 500 or 2000ngmL-1 chlorpyrifos revealed an inhibitory effect on testosterone synthesis in both testicular (control, 40.29pgmg-1 tissue wet weight-1h-1 compared to experimental, 21.84pgmg-1 tissue wet weight-1h-1) and ovarian (control, 33.83pgmg-1 tissue wet weight-1h-1 compared to experimental, 15.19pgmg-1 tissue wet weight-1h-1) tissue. In a second series of experiments, larval Lake Sturgeon were exposed to equivalent concentrations of chlorpyrifos as above for 10days (d) between hatch and the onset of exogenous feeding. Larvae from each treatment group were raised until 67days post hatch (dph) and growth rates were compared alongside key indicators of thyroid follicle growth. Chlorpyrifos treatment had no effect on the measured indicators of thyroid follicular development. © 2015 Elsevier Ltd.

Mcdougall C.A.,North South Consultants Inc. | Pisiak D.J.,North South Consultants Inc. | Barth C.C.,North South Consultants Inc. | Blanchard M.A.,North South Consultants Inc. | And 2 more authors.
Journal of Applied Ichthyology | Year: 2014

Success of lake sturgeon (Acipenser fulvescens Rafinesque, 1817) stocking programmes has rarely been evaluated. As of the early 1990s, Lake Sturgeon populations were nearly extirpated from several sections of the upper Nelson River, Manitoba, at least in part due to historical overexploitation. Between 1994 and 2011, 20 885 fingerlings (age-0, untagged) and 1117 yearlings (age-1, 1014 PIT tagged) were stocked into an upper Nelson River reach. In fall 2012, a Lake Sturgeon population inventory using gill nets assessed post-release survival/retention of stocked fish. Of 91 unique Lake Sturgeon captured, 67 (74%) possessed PIT tags, signifying they were stocked at age-1. Relative recruitment success was conservatively estimated to be 17.7 times greater for age-1 vs age-0 stocked fish based only on PIT tag recapture data. However, including 19 additional fish identified as stocked at age-1 based on atypical 'first' annuli patterns, the revised relative recruitment success rate was 130 times greater for age-1 vs age-0. An interpreted consensus ageing method produced correct age assignment 97% of the time for juveniles of known age, despite complications caused by overwinter growth in the hatchery. © 2014 Blackwell Verlag GmbH.

Nelson P.A.,North South Consultants Inc. | Johnson M.W.,North South Consultants Inc. | Cott P.A.,Fisheries and Oceans Canada Western Arctic Area 101
Comparative Parasitology | Year: 2010

The trout-perch, Percopsis omiscomaycus (Walbaum), is a widely distributed species in North America. Despite several compound community surveys, the northernmost survey of trout-perch parasites is from southern Manitoba, Canada. A total of 42 parasite species have been reported from trout-perch, with 2 species being strictly host specific. During limnological surveys of Sid and Blitzen lakes, Northwest Territories, Canada, 4 parasite taxa were recovered from trout-perch: Protozoan cysts, Diplostomum sp., Proteocephalus sp., and Crepidostomum percopsisi. The present study area is approximately 1,547 km northwest of Dauphin Lake, which is the northernmost documented range for C. percopsisi. These data provide further support for Halvorsen's "constant fauna" as a general rule for north temperate fish parasite communities. Comparisons with other trout-perch surveys from more southern portions of the biogeographic range suggest that parasite composition, at least in small, nutrient- and species-poor lakes at northern latitudes have decreased richness, despite trout-perch having a diverse diet compared with more southern surveys. The intermediate host of C. percopsisi is unknown. Other Crepidostomum spp. are transmitted through Ephemeroptera, which occur in the diet of the trout-perch from Blitzen and Sid lakes. However, the high prevalence of cladocerans in this study, similar to other published reports, might implicate cladocerans as a potential intermediate host for C. percopsisi. © 2010 The Helminthological Society of Washington.

Barth C.C.,North South Consultants Inc. | Anderson W.G.,University of Manitoba
Canadian Journal of Zoology | Year: 2015

Understanding biotic and abiotic factors that influence spatial distribution patterns, condition factor, and growth of lotic fish species within river impoundments is essential for the development of effective management and conservation strategies. This study aimed to compare relative abundance, condition factor, and growth rate of juvenile lake sturgeon (Acipenser fulvescens Rafinesque, 1817) among eight sections of a 41 km long impoundment of the Winnipeg River, Manitoba, Canada. Relative abundance of juvenile lake sturgeon, as measured by catch per unit effort (CPUE), was 3–6 times greater in the two farthest upstream sections when compared with the five farthest downstream sections. Growth in length was slowest for individuals captured in the two farthest upstream sections, moderate in the third section, and highest in the fourth section, with individuals from the fourth section attaining lengths approximately double those from the two farthest upstream sections by age 6. Condition factor varied among sections of the impoundment in a pattern similar to that observed for growth. Given similarities in many environmental factors such as water temperature and water chemistry among sections of this study area, our results provide important insight into how abiotic and biotic factors, combined with behavioural characteristics of this species, may influence distribution patterns and growth of juvenile lake sturgeon within river impoundments. © 2015, National Research Council of Canada, All Rights Reserved.

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