My general area of interest is applied fish physiology. Current research in my lab focuses on two areas. Firstly, we are studying the physiology and behaviour of triploid fish, and assessing the suitability of induced triploidy as a means to sterilize fish for aquaculture. Triploid fish are unique models for physiological research because they have larger (but fewer) cells in their tissues and organs. This allows us to examine the importance of cell size and number to basic physiological processes without having to do inter-species comparisons. Most of this research has focused on hematology, respiratory physiology and stress response, but we have also examined reproductive physiology and nutrient utilization in triploids. This work is of relevance to aquaculture and fisheries management because induced triploidy is seen as the only effective method for the mass-production of reproductively sterile fish, but triploids typically do not perform as well as normal diploids under commercial culture conditions. Our research is meant, in part, to determine the underlying reasons for the differences in performance between triploids and diploids. The second principal area of research in my lab deals with sex determination and gonadal differentiation in fish, and the use of genetic, endocrine and environmental manipulations to produce single-sex populations of fish for aquaculture. We are interested in the biochemical and physiological processes that underlie gonadal differentiation into ovaries and testes in fish, processes which are highly plastic compared to those of mammals. This work has relevance to aquaculture because frequently one sex has better production characteristics (faster growth, later maturity, production of caviar, etc.) that the other. We have collaborated extensively with industry partners on this research and, as a result, have become the world leaders in the production of all-female populations of halibut for commercial aquaculture.

Sacobie, C.F.D, H.A. Burke, S.P. Lall & T.J. Benfey. 2015. The effect of dietary energy level on growth and nutrient utilization by juvenile diploid and triploid brook charr, Salvelinus fontinalis. Aquacult. Nutr.: published on-line Dec. 23, 2015. http://dx.doi.org/10.1111/anu.12347 Benfey, T.J. 2015. Effectiveness of triploidy as a management tool for reproductive containment of farmed fish: Atlantic salmon (Salmo salar) as a case study. Rev. Aquacult.: published on-line Feb. 3, 2015. http://dx.doi.org/10.1111/raq.12092 Thresher, R.E., K. Hayes, N.J. Bax, J. Teem, T.J. Benfey & F. Gould. 2014. Genetic control of invasive fish: technological options and its role in Integrated Pest Management. Biol. Inv. 16: 1201-1216. Trippel, E.A., I.A.E. Butts, A. Babin, S.R.E. Neil, N.J. Feindel & T.J. Benfey. 2014. Effects of reproduction on growth and survival in Atlantic cod, Gadus morhua, assessed by comparison to triploids. J. Exp. Mar. Biol. Ecol. 451: 35-43. Tremblay-Bourgeois, S., N.R. Le François, R.L. Roy, A. Savoie, A.K. Imsland, B.-A. Dupont-Cyr & T.J. Benfey. 2013. Cortisol and behavioural response to handling (acute) and confinement (chronic) stressors in juvenile spotted wolffish, Anarhichas minor: a distinct cold-water aquaculture species. J. Appl. Aquacult. 25: 248-264. Ellis, L.E., C.F.D. Sacobie, J.D. Kieffer & T.J. Benfey. 2013. The effects of dissolved oxygen and triploidy on critical thermal maximum in brook charr (Salvelinus fontinalis). Comp. Biochem. Physiol. 166A: 426-433. Lin, S., T.J. Benfey & D.J. Martin-Robichaud. 2012. Hormonal sex reversal in Atlantic cod, Gadus morhua. Aquaculture 364-365: 192-197. Sacobie, C.F.D., B.D. Glebe, M.A. Barbeau, S.P. Lall & T.J. Benfey. 2012. Effect of strain and ploidy on growth performance of Atlantic salmon, Salmo salar, following seawater transfer. Aquaculture 334-337: 58-64. Whitehead, J.A., T.J. Benfey & D.J. Martin-Robichaud. 2012. Ovarian development and sex ratio of gynogenetic Atlantic cod (Gadus morhua). Aquaculture 324–325: 174–181. Benfey, T.J. 2011. Physiology of triploid fish. In: Encyclopedia of Fish Physiology: From Genome to Environment (A.P. Farrell, ed.), pp. 2009–2015. San Diego: Academic Press. Feindel, N.J., T.J. Benfey & E.A. Trippel. 2011. Gonadal development of triploid Atlantic cod Gadus morhua. J. Fish Biol. 78: 1900-1912. Tudorache, C., R.A. O’Keefe & T.J. Benfey. 2011. Optimal swimming speeds reflect preferred swimming speeds of brook charr (Salvelinus fontinalis Mitchill, 1874). Fish Physiol. Biochem. 37: 307-315. Burke, H.A., C.F.D. Sacobie, S.P. Lall & T.J. Benfey. 2010. The effect of triploidy on juvenile Atlantic salmon (Salmo salar) response to varying levels of dietary phosphorus. Aquaculture 306: 295-301. Feindel, N.J., T.J. Benfey & E.A. Trippel. 2010. Competitive spawning success and fertility of triploid male Atlantic cod (Gadus morhua). Aquacult. Env. Interact. 1: 47-55. Tremblay-Bourgeois, S., N.R. Le François, R.L. Roy, T.J. Benfey & A.K. Imsland. 2010. Effect of rearing density on growth and welfare indices of juvenile spotted wolffish, Anarhichas minor (Olafsen) Aquacult. Res. 41: 1179-1189. Tudorache, C., R.A. O’Keefe & T.J. Benfey. 2010. Flume length and post-exercise impingement affect anaerobic metabolism in brook charr Salvelinus fontinalis. Journal of Fish Biology 76: 729–733. Tudorache, C., R.A. O’Keefe & T.J. Benfey. 2010. The effect of temperature and ammonia exposure on swimming performance of brook charr (Salvelinus fontinalis). Comparative Biochemistry and Physiology 156A: 523–528. Adewolu, M.A. & T.J. Benfey. 2009. Growth, nutrient utilization and body composition of juvenile bagrid catfish, Chrysichthys nigrodigitatus (Actinopterygii: Siluriformes: Claroteidae), fed different dietary crude protein levels. Acta Ichthyologica et Piscatoria 39: 95-101. Chiasson, M.A., C.S. Pelletier & T.J. Benfey. 2009. Triploidy and full-sib family effects on survival and growth in juvenile Arctic charr (Salvelinus alpinus). Aquaculture 289: 244–252. T.J. Benfey & L.E. Bennett. 2009. Effect of temperature on heart rate in diploid and triploid brook charr, Salvelinus fontinalis, embryos and larvae. Comparative Biochemistry and Physiology 152A: 203–206. Chiasson, M., T.J. Benfey & D.J. Martin-Robichaud. 2008. Gonadal differentiation in Atlantic cod, Gadus morhua L., and haddock, Melanogrammus aeglefinus (L.). Acta Ichthyologica et Piscatoria 38: 127-133. Trippel, E.A., T.J. Benfey, S.R.E. Neil, N. Cross, M.J. Blanchard & F. Powell. 2008. Effects of continuous light and triploidy on growth and sexual maturation in Atlantic cod, Gadus morhua. Cybium 32(2) suppl.: 136-138. Hughes, V, T.J. Benfey & D.J. Martin-Robichaud. 2008. Effect of rearing temperature on sex ratio in juvenile Atlantic halibut, Hippoglossus hippoglossus. Environmental Biology of Fishes 81: 415-419. Atkins, M.E. & T.J. Benfey. 2008. Effect of temperature on routine metabolic rate in triploid salmonids. Comparative Biochemistry and Physiology 149A: 157-161. Chiasson, M. & T.J. Benfey. 2007. Gonadal differentiation and hormonal sex reversal in Arctic charr (Salvelinus alpinus). Journal of Experimental Zoology 307A: 527-534.