Tom Johnston

Recherches

Je suis spécialiste de l’écologie des pêches et des poissons pour la section de sciences et de recherche au ministère des Richesses naturelles et des Forêts de l’Ontario et mes recherches appuient et orientent la gestion des pêches dans la province. Je suis aussi membre du corps professoral dans l’École des sciences naturelles à l’Université Laurentienne et mon programme de recherche comprend la direction de projets d’étudiants du premier cycle et des cycles supérieurs. Mon laboratoire est situé au Centre pour la vitalité des lacs Vale, sur les rives du lac Ramsey.

Dans mes recherches, je m’intéresse principalement aux écologies reproductives des poissons, à la structure de la chaîne alimentaire et à la dynamique des contaminants dans les écosystèmes aquatiques du nord ainsi qu’à l’évaluation de la biodiversité aquatique à l’échelle des paysages. Les recherches s’effectuent surtout sur le terrain et portent sur une vaste gamme de lacs et de rivières dans le nord de l’Ontario. Dans mon laboratoire, les études suivantes sont en cours : i) les variations de position de niches trophiques et les dimensions de poissons en fonction des conditions de l’écosystème et de la composition de la communauté; ii) le rétablissement de la biodiversité des poissons dans la zone historique de dépôt d’acide dans le nord-est de l’Ontario; et iii) les interactions entre les effets sur la mère et les facteurs environnementaux et leur incidence sur le succès reproducteur des poissons.

 

Publications (six dernières années)

McMeans, B.C., P.A. Cott, T.A. Johnston, P.J. Blanchfield, M.M. Guzzo, and R.A. Cunjak. 2023. Winter as a defining season for Canadian fishes, pp. 485-507  In  Hasler, C.T., J.G. Imhof, N.E. Mandrak, and S.J. Cooke  (eds.)  Freshwater Fisheries in Canada,  American Fisheries Society, Bethesda, MD, USA.

Kluke, C., G.L. Lescord, B. Kielstra, A. Lock, T.A. Johnston, S. Bhavsar, and J.M. Gunn. 2023. Spatial patterns and environmental factors related to arsenic bioaccumulation in boreal freshwater fish of Ontario, Canada.  Canadian Journal of Fisheries and Aquatic Sciences 80: 628–641.

Lescord, G.L., T.A. Johnston, D.E. Ponton, M. Amyot, A. Lock, and J.M. Gunn. 2022. The speciation of arsenic in the muscle tissue of inland and coastal freshwater fish from a remote boreal region.  Chemosphere 308: 136140.

Johnston, T.A., G.L. Lescord, M. Quesnel, P.-L. Savage, J.M. Gunn, and K.A. Kidd.  2022. Age, body size, growth and dietary habits: what are the key factors driving individual variability in mercury of lacustrine fishes in northern temperate lakes?  Environmental Research 213: 113740.

Ponton, D.E., J. Ruelas-Inzunza, R. Lavoie, G.L. Lescord, T.A. Johnston, J. Graydon, M. Reichert, C. Donadt,

M. Poesch, J.M. Gunn, M. Amyot. 2022. Mercury, selenium and arsenic concentrations in Canadian freshwater fish and a perspective on human consumption intake and risk.  Journal of Hazardous Materials Advances 6: 100060.

Presello, A.J., J.L. Smith, T.D. Drew, K.K. Loftus, T.A. Johnston, C.C. Wilson, and T.E. Pitcher. 2021.  Induction of free-flowing gametes in order to establish a reintroduction broodstock of bloaters (Coregonus hoyi) for Lake Ontario.  Advances in Limnology 66: 363-379.

Johnston, T.A., A.J. Harry, R.D. Montgomerie, M.D. Wiegand, G.A. Spiers, J.M. Casselman, and W.C. Leggett.  2021. Maternal effects on embryonic survival and development in walleyes of Lake Nipissing, Ontario.  Transactions of the American Fisheries Society 150(6): 777-791.

Johnston, T.A., A.D. Ehrman, J.J. Montgomery, and H.K. Swanson. 2021.  Dietary and non-dietary contributions to among-individual variation in carbon and nitrogen isotopic composition of lake trout.  Ecological Indicators 123: 107349.

Johnston, T.A., J.J. Montgomery, G.L. Lescord, K.A. Patterson, L.C. Haslam, K. Tremblay, G.E. Morgan, H.K. Swanson, N. Commanda, S.D. Kaufman and J.M. Gunn. 2021. An isotopic analysis of food web structure and trophic interactions in Lake Nipissing, Ontario. Ontario Ministry of Northern Development, Mines, Natural Resources and Forestry, Science and Research Branch, Peterborough, ON. Science and Research Technical Report TR-45. 62 p. + appendices

Johnston, T.A., J.M. Casselman, and W.C. Leggett. 2021.  Sex-based divergence in isotopic compositions of north temperate freshwater fishes.  Hydrobiologia 848: 873-884.

Thomas, S., S. Melles, R. Mackereth, T. Tunney, C. Chu, C. Oswald, S. Bhavsar, and T.A. Johnston. 2020. Climate and landscape conditions indirectly affect fish mercury levels by altering lake water chemistry and fish size.  Environmental Research 188: 109750.

Johnston, T.A., M.D. Wiegand, R.L. Szmydala, L.R. Porteous, J.M. Casselman, and W.C. Leggett. 2020.  Sex-based differences in fatty acid composition of adult walleye.  Ecology of Freshwater Fish 29: 654-664.

Patterson, K.A., T.A. Johnston, L.C. Haslam, W. Keller, G.L. Lescord, M.J. Heerschap, R.A. DeJong, H.K.

Swanson, P.A. Lennox, C-L.B. Chetkiewicz, C.M. O’Connor, J.W. Warmbold, J.L. Bailey, B.A. Edwards, M.T. Arts, C.J. Chenier, A.W. Sumner, R.W.K. Tang, B.A. Branfireun, N.E. Jones, S.P. Bhavsar and J.M. Gunn. 2020. Fish and aquatic sampling activities in the Hudson Bay Lowlands Ecozone of the Far North of Ontario: 2008-2018. Ontario Ministry of Natural Resources and Forestry, Science and Research Branch, Peterborough, ON. Science and Research Technical Report TR-41. 54 p. + appendices.

Johnston, T.A., K.A. Patterson, L.C. Haslam, S.J. Scholten, J.M. Gunn and C.D. Wren. 2020. Limnological and fish community surveys of Tadenac Lake and Tadenac Bay (Georgian Bay, Lake Huron), 2011–2014. Ontario Ministry of Natural Resources and Forestry, Science and Research Branch, Peterborough, ON. Science and Research Technical Report TR-39. 39 p. + appendix.

Sumner, A.W., T.A. Johnston, G.L. Lescord, B.A. Branfireun, and J.M. Gunn. 2020. Mercury bioaccumulation in lacustrine fish populations along a climatic gradient in northern Ontario, Canada.  Ecosystems 23: 1206–1226.

Lescord, G.L., T.A. Johnston, M.J. Heerschap, W. (Bill) Keller, F.M. Southee, C.M. O’Connor, R.D. Dyer, B.A. Branfireun, and J.M. Gunn. 2020.  Arsenic, chromium, and other elements of concern in fish from remote boreal lakes and rivers: drivers of variation and implications for subsistence consumption.  Environmental Pollution 259: 113878.

Mozzon, C.M., G.L. Lescord, P.-L. Savage, and T.A. Johnston. 2020.  The trophic niche of sculpins (Cottus spp.) in forage fish assemblages of boreal lakes. Journal of Fish Biology 96: 92-101.

Lescord, G.L., T.A. Johnston,  B.A. Branfireun, and J.M. Gunn. 2019. Mercury bioaccumulation in relation to changing physicochemical and ecological factors across a large and undisturbed boreal watershed.  Canadian Journal of Fisheries and Aquatic Sciences 76: 2165-2175.

Johnston, T.A., A.D. Ehrman, G.L. Hamilton, B.K. Nugent, P.A. Cott, and J.M. Gunn.  2019.  Plenty of room at the bottom: niche variation and segregation in large-bodied benthivores of boreal lakes.  Canadian Journal of Fisheries and Aquatic Sciences 76: 1411-1422.

Lescord, G., T.A. Johnston, B. Branfireun, and J.M. Gunn.  2018.  Percentage of methylmercury in the muscle tissue of freshwater fish varies with body size and age and among species. Environmental Toxicology and Chemistry 37: 2682-2691.

Johnston, T.A.  2018. Egg size and lipid content of lake trout, Salvelinus namaycush, in the wild and in captivity. Canadian Journal of Fisheries and Aquatic Sciences 75: 2123-2135.

Lescord, G., E. Emilson, T.A. Johnston, B. Branfireun, and J.M. Gunn. 2018. Optical properties of dissolved organic matter and their relation to mercury concentrations in water and biota across a remote freshwater drainage basin.  Environmental Science and Technology 52: 3344-3353.