Fluvial Ecosystem Research Section

Montréal, Canada

Fluvial Ecosystem Research Section

Montréal, Canada
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Marcogliese D.J.,Fluvial Ecosystem Research Section | Pulkkinen K.,University of Jyväskylä | Valtonen E.T.,University of Jyväskylä
Archives of Environmental Contamination and Toxicology | Year: 2012

Wild-caught European perch (Perca fluviatilis) were exposed in the laboratory to untreated bleached pulp and paper mill effluent in two separate experiments. The first experiment was conducted at 7-8°C using effluent concentrations of 5 and 10%, and the second experiment was conducted at ambient river temperature of 4-20°C using an effluent concentration of 1%. Trichodinid ciliates were identified and enumerated at the end of the exposure using a mucus subsampling technique from gill and skin as well as a formalin immersion technique, which provided total counts on each fish. Four different trichodinid species were identified on the fish. Prevalence of infection, mean number, and mean density of Trichodina spp. decreased on fish exposed to effluents compared with controls. Prevalence of infection, mean number, and mean density of Trichodinella epizootica decreased on fish exposed to 5% and 10% effluents but increased on fish exposed to 1% effluents compared with controls. These results demonstrate that trichodinid ciliates vary in their susceptibility to at least certain types of contaminants and cautions against using trichodinids as environmental indicators without delineating species. © Her Majesty the Queen in Right of Canada 2011.

Gheorghiu C.,Wilfrid Laurier University | Marcogliese D.J.,Fluvial Ecosystem Research Section | Scott M.E.,McGill University
Diseases of Aquatic Organisms | Year: 2012

The present study assessed the histological changes in the epidermis of Poecilia reticulata induced by the combined effects of an ectoparasite Gyrodactylus turnbulli and differing concentrations of waterborne zinc (Zn). Infected guppies were exposed to 0, 15, 30, 60, or 120 μg Zn l-1 and monitored over 3 wk during the exponential increase in parasite numbers on the fish. The fish epidermis responded within 3 d to G. turnbulli infection with a rapid increase in epidermal thickness and a modest increase in number, but not size or composition, of mucous cells. In contrast, in the presence of combined waterborne Zn and infection, mucous cell numbers declined rapidly. As the parasite numbers increased, the epidermis remained thicker than normal, and the number and size of mucous cells decreased. The addition of Zn led to a dramatic thickening of the epidermis during the exponential growth of the parasite population. Mucous cell numbers remained depressed. Temporal changes in mucous cell size were Zn concentration dependent. At 60 μg Zn l-1, cells returned to normal size as infection progressed, whereas they remained extremely small at 120 μg Zn l-1. Changes in mucin composition previously reported in response to Zn alone were subdued in the presence of the parasite except at 60 μg Zn l-1, where all cells contained only acidic mucins. Together these results demonstrate that, on exposure to both Zn and G. turnbulli infection, the epidermal response is initially a protective response to both stressors, and then mainly driven by the increased parasite burden. © Inter-Research 2012.

Koprivnikar J.,Brandon University | Marcogliese D.J.,Fluvial Ecosystem Research Section | Rohr J.R.,University of South Florida | Orlofske S.A.,University of Colorado at Boulder | And 2 more authors.
EcoHealth | Year: 2012

Understanding linkages between environmental changes and disease emergence in human and wildlife populations represents one of the greatest challenges to ecologists and parasitologists. While there is considerable interest in drivers of amphibian microparasite infections and the resulting consequences, comparatively little research has addressed such questions for amphibian macroparasites. What work has been done in this area has largely focused on nematodes of the genus Rhabdias and on two genera of trematodes (Ribeiroia and Echinostoma). Here, we provide a synopsis of amphibian macroparasites, explore how macroparasites may affect amphibian hosts and populations, and evaluate the significance of these parasites in larger community and ecosystem contexts. In addition, we consider environmental influences on amphibian-macroparasite interactions by exploring contemporary ecological factors known or hypothesized to affect patterns of infection. While some macroparasites of amphibians have direct negative effects on individual hosts, no studies have explicitly examined whether such infections can affect amphibian populations. Moreover, due to their complex life cycles and varying degrees of host specificity, amphibian macroparasites have rich potential as bioindicators of environmental modifications, especially providing insights into changes in food webs. Because of their documented pathologies and value as bioindicators, we emphasize the need for broader investigation of this understudied group, noting that ecological drivers affecting these parasites may also influence disease patterns in other aquatic fauna.

Locke S.A.,Concordia University at Montréal | Locke S.A.,Fluvial Ecosystem Research Section | Daniel McLaughlin J.,Concordia University at Montréal | Marcogliese D.J.,Fluvial Ecosystem Research Section
Molecular Ecology | Year: 2010

Diplostomoid metacercariae parasitize freshwater fishes worldwide and cannot be identified to species based on morphology. In this study, sequences of the barcode region of cytochrome c oxidase subunit 1 (CO1) were used to discriminate species in 1088 diplostomoids, most of which were metacercariae from fish collected in the St. Lawrence River, Canada. Forty-seven diplostomoid species were detected, representing a large increase in known diversity. Most species suggested by CO1 sequences were supported by sequences of internal transcribed spacer (ITS) of rDNA and host and tissue specificity. Three lines of evidence indicate that physiological incompatibility between host and parasite is a more important determinant of host specificity than ecological separation of hosts and parasites in this important group of freshwater fish pathogens. First, nearly all diplostomoid species residing outside the lens of the eyes of fish are highly host specific, while all species that occur inside the lens are generalists. This can be plausibly explained by a physiological mechanism, namely the lack of an effective immune response in the lens. Second, the distribution of diplostomoid species among fish taxa reflected the phylogenetic relationships of host species rather than their ecological similarities. Third, the same patterns of host specificity were observed in separate, ecologically distinctive fish communities. © 2010 Her Majesty the Queen in Right of Canada.

King K.C.,Concordia University at Montréal | Daniel Mclaughlin J.,Concordia University at Montréal | Boily M.,University of Quebec at Montréal | Marcogliese D.J.,Fluvial Ecosystem Research Section
Biological Conservation | Year: 2010

Native amphibian populations are shrinking worldwide, and both parasitic infections and environmental stress from agriculture have been implicated. We investigated the principal hypothesis that environmental by-products of agricultural activity mediate parasitism in native frogs. Bullfrogs were collected from wetlands with variable landscape disturbance and water quality and examined for helminth parasites. We predicted that pesticide pollution and landscape development would be significant factors shaping the parasite communities and populations. Parasite diversity and species richness were lower in wetlands impacted by both pesticides and land use. Two parasite groups, direct life-cycle nematodes and echinostomes, were common in polluted habitats, potentially increasing frog pathology and mortality risk. In areas with agricultural landscape and reduced forest cover, parasite diversity and species richness were low, perhaps because of less parasite transmission from birds and mammals. This result suggests that land development limits terrestrial vertebrate access to wetlands. Our results indicate that parasite abundance and community structure in wetlands are influenced by factors operating locally within the wetland and more broadly in the surrounding landscape. We suggest that parasite communities in amphibians are effective indicators of ecosystem health and animal biodiversity, and thus useful tools for conservation biology. Crown Copyright © 2009.

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