Contact Gerald Tetreault:

Phone & Address


University of Waterloo (Adjunct)

Canadian Water Network

Canadian Rivers Institute


Ph.D. (Aquatic Toxicology) University of Waterloo, Waterloo

M.Sc. (Aquatic Toxicology) University of Waterloo, Waterloo

B.Sc. Hon. (Biology) University of Guelph, Guelph


Gerald Tetreault

Research Technician - Ecosystem Health Assessment

CURRENT S&T / RESEARCH - Evaluating the effects of contaminants on fish populations, community structure and reproductive health of fish

  • Effects of Municipal Wastewater effluents in Canadian receiving environments
  • Adverse physiological effects of natural and synthetic hormones, and pharmaceuticals leading to endocrine disruption in wild fish
  • Field sampling to determine impacts on fish populations exposed to oil sands effluents in northern Alberta, pulp and paper effluents, and agricultural run-off
  • How does impaired fish health influence changes in the fish community structure
  • Assesment of fish health adjacent to oil sands operations
  • Cumulative Effects Assessment on a watershed scale


Served on Board of Directors for the Aquatic Toxicity Workshop (2005-2007), as well as ATW 2003 & 2006 Meeting Organizing Committee Member

Co-organized the Grand River Watershed Research Forum (2005 &2006) and member of the Grand River Conservation Authority Fisheries Management Implementation Plan Committee, Cambridge, ON

Canadian Water Network Student Executive Committee (2006)

Member of Society of Environmental Toxicology and Chemistry (SETAC) (since 1999) and SETAC Laurentian Chapter (since 2006)


Tetreault GR, Kleywegt S, Marjan P, Bragg L. Arlos M, Fuzzen ML, Smith B, Massarky A, McMaster ME, Moon T, Meltcalfe C, Oakes K, Servos MR. 2015. Response of fish to remedial actions at select sewage treatment plants in the Grand River. In prep.

Pinheiro MDO, Simmons DBD, Villella M, Tetreault G R, Muir DCG, McMaster ME, Hewitt LM, Parrott JL, Brown SB, Sherry JP. 2015. Wild fish health at the St. Lawrence River (Cornwall) Area of Concern: potential links between endocrine-related effects and elevated concentrations of PCBs and mercury. In prep.

Robinson CS, Tetreault GR, McMaster ME, Servos MR. 2015. Differential response of two darters species (Etheostoma blennioides and E. caeruleum) to tertiary treated municipal wastewater effluent in a small receiving environment. Accepted in Ecol Ind

Dahmer SC, Tetreault GR, Hall RI, Munkittrick KR, McMaster ME, Servos MR. 2015. Historical trends of polychlorinated dibenzo-p-dioxins and dibenzofurans in white sucker (Catostomus commersoni) liver and dated sediment cores from Jackfish Bay, Lake Superior. Accepted in Environ Toxicol Chem

Fuzzen ML, Bennett CJ, Tetreault GR, McMaster ME, Servos MR. 2015. Severe intersex is predictive of poor fertilization success in populations of rainbow darter (Etheostoma caeruleum). Accepted in Aquat Toxicol

Stanfield LW, Del Giudice L, Lutscher F, Trudeau M, Alexander L, Fagan WF, Fertik R, Mackereth R, Richardson JS, Shrestha N, Tetreault G, Wipfli MS. 2014. A Discussion Paper on: Cumulative effects from alteration of headwater drainage features and the loss of ecosystem integrity of river networks. Ontario Ministry of Natural Resources, Glenora, Ontario 21pp

Bahamonde PA, Fuzzen MM, Bennett CJ, Tetreault GR, McMaster ME, Servos MR, Martyniuk CJ, Munkittrick KR. 2014. Intersex severity in rainbow darter (Etheostoma caeruleum) in the Grand River basin, ON, Canada. Part A. Accepted in Aquat Toxicol

Bahamonde PA, Tetreault GR, McMaster ME, Servos MR, Martyniuk CJ, Munkittrick KR. 2014. Molecular signatures in rainbow darter (Etheostoma caeruleum) inhabiting an urbanized river reach receiving wastewater effluents. Aquat Toxicol 148:211-220.

Tetreault, G. R., Bennett, C. J., Servos, M.R., McMaster, M.E. 2014. Optimization of effects-assessment of Greenside Darter (Etheostoma blennioides) exposed to tertiary treated municipal wastewater based on seasonal changes of reproductive endpoints. Environ Toxicol Chem DOI: 10.1002/etc.2526.

Feswick A, Ankley GT, Denslow N, Ellestad LE Fuzzen M, Jensen KM, Kroll K, Lister A, MacLatchy DL, McMaster ME, Orlando EF, Servos MR, Tetreault GR, Van Den Heuvel MR, Munkittrick KR. 2014 An inter-laboratory study on the variability in measured concentrations of 17β-estradiol, testosterone and 11-ketotestosterone in white sucker: implications and recommendations. Environ Toxicol Chem DOI: 10.1002/etc.2503

Tetreault GR, Brown CJM, Bennett CJ, Oakes KD, McMaster ME, Servos MR. 2013. Fish community responses to multiple municipal wastewater inputs in a watershed. Integ Ecosyst Assess Manage DOI: 10.1002/ieam.1364

Brasfield SM, Tetreault GR, McMaster ME, Bennett J, Munkittrick KR. 2013. Seasonal patterns of gonad size, liver size, and in vitro gonadal steroidogenic capacity in slimy sculpin (Cottus cognatus). Water Qual Res J Can 48(3):243-254

Tanna R, Tetreault GR, Bennett CJ, Smith B, Bragg L, Oakes K, McMaster ME, Servos MR. 2013 Occurrence and degree of intersex (testis-ova) across an urban gradient in the Grand River, Ontario, Canada. Environ Toxicol Chem (doi/10.1002/ect.2262)

Tetreault GR, Bennett CJ, Cheng C, Servos MR, McMaster ME. 2012. Reproductive and histopathological effects in wild fish inhabiting an effluent-dominated stream, Wascana Creek, SK, Canada. Aquat Toxicol 110-111:149-161

Boxall AB, Rudd MA, Brooks BW, Caldwell DJ, Choi K, Hickmann S, Innes E, Ostapyk K, Staveley JP, Verslycke T, Ankley GT, Beazley KF, Belanger SE, Berninger JP, Carriquiriborde P, Coors A, Deleo P.C., Dyer SD, Ericson JF, Gagné F, Giesy JP, Gouin T, Hallstrom L, Karlsson MV, Larsson DG, Lazorchak JM, Mastrocco F, McLaughlin A, McMaster ME, Meyerhoff RD, Moore R, Parrott JL, Snape JR, Murray-Smith R, Servos MR, Sibley PK, Straub JO, Szabo ND, Topp E, Tetreault GR, Trudeau VL, Van Der Kraak G.2012. Pharmaceuticals and personal care products in the environment: what are the big questions? Environ Health Perspect 120(9):1221-9 doi: 10.1289/ehp.1104477

Tetreault GR, Bennett CJ, Shires K, Knight B, Servos MR, McMaster ME. 2011. Intersex and reproductive impairment of two species wild fish exposed to multiple municipal wastewater discharges. Aquat Toxicol 114:278-290

Brown CJM, Knight BW, McMaster ME, Munkittrick KR, Oakes KD, Tetreault GR, Servos MR. 2011. The effects of tertiary treated municipal wastewater on fish communities of a small river tributary in Southern Ontario, Canada. Environ Poll 159:1923-1931

Chiang G, Munkittrick KR, Saavedra MF, Tucca F, McMaster ME, Urrutia R, Tetreault G, Gavilan JF, Barra R. 2010. Seasonal changes in reproductive endpoints in Trichomycterus areolatus (Siluriformes: Trichomycteridae) and Percilia (Perciformes, Percilidae) and the consequences for environmental monitoring. Study Neotrop Fauna Environ 46(3):185-196


Tetreault G, McMaster M, Bennett J, Spina S, McInnis R, McKeag A, Servos M. 2009. Investigation of community, population and individual responses of fish exposed to multiple municipal wastewater effluents in Canada. Can Tech Rep Fish Aquat Sci no. 2841:124


Bowron LK, Munkittrick KR, McMaster ME, Tetreault GR, Hewitt LM. 2009. Responses of white sucker (Catostomus commersoni) to 20 years of process and waste treatment changes at a bleached kraft pulp mill, and to mill shutdown. Aquat Toxicol 95:117-132

Farwell AJ, Parrott JL, Sherry JP, Tetreault GR, Van Meer T, Dixon DG. 2009. Use of stable carbon and nitrogen isotopes to trace natural and anthropogenic inputs into riverine systems in the Athabasca Oil Sands region. Water Qual Res J Can 44(2)               

McDaniel TV, Martin PA, Struger J, Sherry J, Marvin CH, McMaster ME, Clarence S, Tetreault G. 2008. Potential endocrine disruption of sexual development in free ranging male northern leopard frogs (Rana pipiens) and green frogs (Rana clamitans) from areas of intensive row crop agriculture. Aquat Toxicol 88(4):230-242

Palace V, Wautier K, Evans R, Blanchfield P, Mills K, Chalanchuk S, Godard D, McMaster M, Tetreault G, Peters L, Vanderbyllaardt L, and Kidd K. 2006. Biochemical and Histopathological Effects of Ethynylestradiol in Pearl Dace (Semotilus margarita) Exposed to the Synthetic Estrogen in a Whole Lake Experiment. Environ Toxicol Chem 25(4):1114-1125

McMaster ME, Hewitt LM, Tetreault GR, Janoscik T, Boyco C, Peters L, Parrott JL, Van der Kraak GJ, Portt CB, Kroll KJ, Denslow ND. 2005. Detailed endocrine assessments of wild fish in the Northern River Basins, Alberta, in comparison to EEM monitored endpoints. Water Qual Res J Can 40(3):299-314

McMaster ME, Hewitt LM, Tetreault GR, Van Der Kraak GJ, Portt CB, Denslow N. 2004. Detailed endocrine assessments in wild fish within the Northern Rivers Basins. Environment Canada, Northern Rivers Ecosystem Initiative: Collective Findings

Tetreault GR, McMaster ME, Dixon GD, Parrott JL. 2003. Using reproductive endpoints in small forage fish species to evaluate the effects of Athabasca Oil Sands activities on the environment. Environ Toxicol Chem 22(11):2775-2782

Tetreault GR, McMaster ME, Dixon GD, Parrott JL. 2003. Physiological and biochemical responses of Ontario Slimy sculpin (Cottus cognatus) to sediment from the Athabasca Oil Sands Area. Water Qual Res J Can 38(2):361-377

Expertise Categories associated with this S&T Expert:

     Aquatic Ecosystems
          Cumulative effects
Nature & Wildlife
          Ecosystem health
          Great Lakes-St. Lawrence
          Peace Athabasca Delta
     Effects of Toxics
          Bioindicator species
          Chemical and biological analysis
          Cumulative effects
          Emerging chemicals
          Endocrine disruption
          Environmental stressors
          Food web transfer
          Oil Sands
          Persistent organic pollutants (POPs)
          Pesticides and herbicides
          Polycyclic aromatic hydrocarbons (PAHs)
          Sub-organismal level (cellular, molecular)
Pollution & Waste
          Persistent organic pollutants (POPs)
          Pesticides and herbicides
          Paper mills
          Persistent organic pollutants (POPs)
          Pharmaceuticals and personal care products
          Aquatic organisms
          Inland waters
     Great Lakes
          Oil sands
          Pulp and paper
     Water Quality
          Bioassays, biomarkers