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Brook Trout's Thermal Tolerance in a Potentially Warming World

Paper Reviewed
Stitt, B.C., Burness, G., Burgomaster, K.A., Currie, S., McDermid, J.L. and Wilson, C.C. 2014. Intraspecific variation in thermal tolerance and acclimation capacity in brook trout (Salvelinus fontinalis): Physiological implications for climate change. Physiological and Biochemical Zoology 87: 15-29.

Writing in Physiological and Biochemical Zoology, Stitt et al. (2014) say that "cold-water fishes are becoming increasingly vulnerable as changing thermal conditions threaten their future sustainability," noting that "thermal stress and habitat loss from increasing water temperatures are expected to impact population viability, particularly for inland populations with limited adaptive resources." But is this really so?

To find out, the six scientists studied the upper thermal tolerance and capacity for acclimation in three captive populations of brook trout (Salvelinus fontinalis), which they obtained from three different ancestral environments that differed in their upper thermal tolerance and capacity for acclimation. And building on a number of pioneering studies of thermal performance in cold-water fish (e.g., Fry et al., 1946; Brett, 1952; Brett et al., 1958; McCauley, 1958), they say their research revealed that "populations can possess substantial thermal acclimation capacity, as well as heritable variation in thermal tolerance among populations," while further citing in this regard the work of Danzmann et al. (1998) and Timusk et al. (2011).

More specifically, Stitt et al. report that the three populations they studied "differed in their upper thermal tolerance and capacity for acclimation, consistent with their ancestry," in that "the northernmost strain had the lowest thermal tolerance, while the strain with the most southern ancestry had the highest thermal tolerance." And they therefore concluded that "with changing climatic conditions, populations of brook trout may have some degree of plasticity to cope with acute and chronic thermal stressors."

References
Brett, J.R. 1952. Temperature tolerance in young Pacific salmon, genus Oncorhynchus. Journal of the Fisheries Research Board of Canada 9: 265-323.

Brett, J.R., Hollands, M. and Alderdice, D.F. 1958. The effect of temperature on the cruising speed of young sockeye and coho salmon. Journal of the Fisheries Research Board of Canada 15: 587-605.

Danzmann, R.G., Morgan, I.R.P., Jones, M.W., Bernatchez, L. and Ihssen, P.E. 1998. A major sextet of mitochondrial DNA phylogenetic assemblages extant in eastern North American brook trout (Salvelinus fontinalis): distribution and postglacial dispersal patterns. Canadian Journal of Zoology 76: 1300-1318.

Fry, F.E.J., Hart, J.S. and Walker, K.F. 1946. Lethal temperature relations for a sample of young speckled trout, Salvelinus fontinalis. Publications of the Ontario Fisheries Research Laboratory 66: 1-35.

McCauley, R.W. 1958. Thermal relations of geographic races of Salvelinus. Canadian Journal of Zoology 36: 655-662.

Timusk, E.R., Ferguson, M.M., Moghadam, H.K., Norman, J.D., Wilson, C.C. and Danzmann, R.G. 2011. Genome evolution in the fish family Salmonidae: generation of a brook charr genetic map and comparisons among charrs (Arctic charr and brook charr) with rainbow trout. BMC Genetics 12: 2-15.

Posted 12 November 2014