Global Issues On The State Of The St. Lawrence: Presentations

Collapse of the Yellow Perch in Lake Saint Pierre: How Did We Get There and What Can We Do About It?

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Christiane Hudon

Researcher, plant community dynamics
Fluvial Ecosystem Research Section
Environment Canada

Christiane Hudon focuses on the cumulative effects of human activities on the productivity and metabolism of major rivers, specifically the St. Lawrence. She uses microscopic algae and aquatic plants as indicators of water quality and quantity. Christiane obtained a PhD in marine biology from Université Laval and has worked as a research scientist at Environment Canada since 1993. As an expert for the Government of Canada, she offered her scientific opinion on the evaluation of alternative plans for regulating the flow from Lake Ontario to the St. Lawrence (International Joint Commission) and on adopting Canadian regulations for the reduction of phosphorus levels in household detergents.

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Philippe Brodeur

Ministère des Ressources naturelles du Québec

Philippe Brodeur has a master’s degree in environmental science from the Université du Québec à Trois Rivières, where his research focused on controlling White Suckers in brook trout lakes in Quebec. He has worked as a biologist for Quebec’s Ministère des Ressources naturelles since 2002 and is currently assigned to the monitoring and management of St. Lawrence fish populations in the Mauricie and Centre du-Québec regions. Over the past few years, he has taken part in several research and monitoring projects on the state of wetlands and fish populations, as well as work on habitat restoration in the St. Lawrence flood plain.


Collaborative presentation by Antonella Cattaneo, Anne-Marie Tourville Poirier, Pierre Dumont, Yves Mailhot, Jean-Pierre Amyot, Simon-Pierre Despatie and Yves de Lafontaine.

In the mid 1990s, there was a significant drop in the abundance of Yellow Perch. Despite restrictive fisheries management measures between 1997 and 2008, the Yellow Perch population collapsed. Various components of the Lake Saint Pierre ecosystem (submerged macryphytes, benthic invertebrates, fish communities and juvenile Yellow Perch) were sampled on the southern shoreline during the Yellow Perch decline period. A vegetation bed fed by agricultural streams and a nitrogen-deficient treated area located further downstream were compared. In addition to a reduction in macrophyte biomass in the treated area, the replacement of green filamentous algae in the agricultural area by mats of benthic cyanobacteria in the treated area was documented. Those changes led to cascading effects, from the decline in the abundance of macrophytes to a decreased availability of invertebrates and a reduction in the growth and survival potential of Yellow Perch. Further to this deterioration of growing zones was the anthropogenic modification of spawning and fry rearing areas in flood plains as well as the arrival of new competitors and predators. Findings on the poor state of Lake Saint Pierre indicate that the situation will only recover once the Yellow Perch is able to breed and develop in a healthy environment. Specifically, vital habitats in the Lake Saint Pierre shorefront will need to be restored, and the water quality from streams will need to be improved. The success of this large restoration project will largely depend on our ability to reduce anthropogenic pressures on this ecosystem.


One hypothesis is that the stocks collapsed around 1994 or 1995. There is indeed a study that indicates a good brood year followed by a significant decline.

For a long time, there was a link between the growth and size of the Yellow Perch cohort. However, during the 2000s, this correlation weakened, which therefore seems be more of an argument for habitat degradation as the cause. There is no information linking this issue to the opening of the Montréal water treatment plant.

12 Years of Monitoring Emerging Contaminants: St. Lawrence Results and Perspectives

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David Berryman

Ministère du Développement durable, de l’Environnement, de la Faune et des Parcs


David Berryman holds a bachelor’s degree in biology from the Université du Québec à Rimouski and a master’s degree in water science from the Institut national de la recherche scientifique (INRS-ETE). Over the course of his work for the MDDEFP, he has conducted several studies on the contamination of southern Quebec watercourses by toxic substances, including several emerging contaminants.


The MDDEFP started monitoring emerging contaminants in southern Quebec watercourses at the end of the 1990s. Studies have been conducted on ethoxylated nonylphenol, phthalates, polybrominated diphenyl ethers (PBDEs), perfluorinated compounds, drug residues, hormones, bisphenol A, triclosan and other products. What lessons have we learned from monitoring?

Identifying a New Generation of Flame Retardants in a St. Lawrence Seagull: Is the PBDE Saga Repeating Itself?

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Jonathan Verreault

Centre de recherche en toxicologie de l’environnement (TOXEN)
Département des sciences biologiques, Université du Québec à Montréal


Jonathan Verreault is a professor at the Département des sciences biologiques at UQAM and is a member of TOXEN. He also holds the Canada Research Chair in comparative toxicology in avian species. His research program aims to better understand the fate, sources and health impacts of emerging contaminants on wildlife species in at-risk ecosystems in industrialized regions and in the Arctic.


Polybrominated diphenyl ethers (PBDEs) have been used on a massive scale over the last few decades in consumer products (electronic devices, textiles, construction materials, etc.) to reduce their flammability. Recent international restrictions on the use of penta-BDE and octa-BDE mixtures, as well as the coming restriction on deca-BDE mixtures (2013) are such that the use of certain unregulated flame retardants has risen and that new compounds are appearing on the market. These emerging flame retardants include 2 ethylhexyl-tetrabromophthalate (TBPH), 2-ethylhexyl-2,3,4,5-tetrabromobenzoate (TBB), Dechlorane-Plus (DP) and organophosphate triesters (RFOP). The aim of this presentation is to give a brief overview of PBDEs and the “new generation” of flame retardants identified in samples from gulls nesting along the St. Lawrence River downstream from Montréal. Do these new flame retardants require more rigorous environmental monitoring? Should we be concerned about their potential impact on the health of wildlife species?

Impacts of Climate Change on Hydrologic Inputs of the Great Lakes and St. Lawrence River Watersheds

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Biljana Music



Biljana Music has worked as a researcher at Ouranos since 2007 in the field of climate science. She has extensive training in atmospheric sciences (BSc and MSc in meteorology from the University of Belgrade and a Diplôme d’études supérieures spécialisées in meteorology from UQAM) and holds a PhD in environmental sciences from UQAM. Her research contributes to advancements in knowledge regarding the capabilities and limitations of climatic models in quantifying the water cycle at the watershed level. She is current leading a project on the impacts of climate change on water inputs of the Great Lakes–St. Lawrence system.

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Richard Turcotte

Centre d’expertise hydrique du Québec
Ministère du Développement durable, de l’Environnement, de la Faune et des Parcs


Richard Turcotte has training in civil engineering from Université Laval, including master’s studies with a specialization in hydrodynamic modelling. He also has a PhD in water science from the Institut national de la recherche scientifique (INRS) in the field of hydrological modelling. He worked at the INRS from 1994 to 2000 in the development and application of hydrological modelling in the integrated management of watersheds. In 2000 he joined the Centre d’expertise hydrique du Québec -- an agency of Quebec’s Ministère du Développement durable, de l’Environnement et de la Faune et des Parcs -- where he is currently the scientific assistant to the director of water expertise.

His main area of activity involves applying hydrological and hydrodynamic modelling to a variety of applied mandates (flow forecasting, projection of climate changes, water management, flood prone areas, etc.). Since January 2008, Dr. Turcotte has been coordinating departmental activities in parallel with activities from the water resources component of Ouranos’ “Impacts et Adaptation” group.


The presentation has two parts. The first will address the Great Lakes watershed (by Biljana Music, Ouranos). This watershed will mainly be examined through components of its water balance, namely the precipitation that falls on the lakes, the evaporation from the surface of the lakes and the drainage from their watersheds. These components will be analyzed in order to provide an overview of anticipated future changes. Our analyses will be put into perspective using recent studies in the Great Lakes scientific community. The second part will address inputs from the watersheds of St. Lawrence tributaries along the Montréal Tadoussac section (by Richard Turcotte, CEHQ). Based on a wide range of climate projections, the second presentation will outline the changes expected from these watersheds’ natural surface water regime. It should be noted that the analyses presented address the subwatersheds of St. Lawrence tributaries and are limited to changes in the inputs entering the St. Lawrence from these subwatersheds. The possible impacts on levels and flows in the St. Lawrence have not been included in the analysis at this stage.


The content of the presentation did not explain whether the storm track is influencing the local increase in flow despite the decreasing water levels in the Great Lakes. However, over the long term, all weather elements are significant and depend on location. The low water levels will likely be more pronounced in the future.

Over the years, water levels will undergo moderate change. However, over short periods (seasons), more severe changes are expected, with more pronounced low water levels. A good example would be the Montréal situation in 2012, where the water level was 1 m lower than the 0 of the hydrographic charts.

Deoxygenation and Acidification of the Deep Waters in the Gulf of St. Lawrence

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Denis Gilbert

Physical oceanographer
Environmental and Ocean Sciences Branch Fisheries and Oceans Canada


Denis Gilbert is an oceanographer with 21 years of experience researching the ocean’s climate. From 2005 to 2010, he led an international working group on the causes and effects of low dissolved oxygen levels in coastal areas. He is a member of the national executive committee for the Canadian Meteorological and Oceanographic Society (CMOS). He directs the Argo Canada program, which conducts long-term monitoring of the worldwide oceanic climate using autonomous subsurface floats.


South of Newfoundland, the proportion of Gulf Stream waters entering the Laurentian Channel has gone from 28% in the 1930s to 47% in the mid 1980s, creating a rise in temperature and salinity, along with a drop in oxygen and pH (acidification) in the deep waters of the Gulf of St. Lawrence. At this time, it is not possible to attribute these major changes to global warming due to the low spatial resolution of the computational grids used in the currently available ocean-ice-atmosphere coupled models.