Effects of repeated daily acute heat challenge on the growth and metabolism of a cold-water stenothermal fish.

Guzzo, M. M., Mochnacz, N. J., Durhack, T., Kissinger, B. C., Killen, S. S. and Treberg, J. R. (2019) Effects of repeated daily acute heat challenge on the growth and metabolism of a cold-water stenothermal fish. Journal of Experimental Biology, 222, jeb198143. (doi:10.1242/jeb.198143) (PMID:31097605)

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Abstract

Temperature is an important environmental factor influencing fish physiology that varies both spatially and temporally in ecosystems. In small north-temperate lakes, cold water piscivores rely on nearshore prey; however, this region exceeds the optimal temperature of the foraging species during summer. To cope, piscivores make short excursions into the nearshore to feed and return to cold water to digest, but the physiological impacts of these repeated acute exposures to warm water are not well understood. We exposed juvenile lake trout ( ) to treatments where they were held at ≈10°C and exposed to either 17 or 22°C for 5 - 10 min daily for 53 days mimicking warm-water forays. Control fish, held at an average temperature of ≈10°C but not exposed to thermal variation, consumed more food and grew slightly faster than heat challenged fish, with no clear differences in body condition, hepatosomatic index, ventricle mass, or muscle concentrations of lactate dehydrogenase and cytochrome c oxidase. Aerobic metabolic rates measured at 10°C indicated that standard metabolic rates (SMR) were similar among treatments; however, fish that were repeatedly exposed to 17°C had higher maximum metabolic rates (MMR) and aerobic scopes (AS) than control fish and those repeatedly exposed to 22°C. There were no differences in MMR or AS between fish exposed to 22°C and control fish. These results suggest that although SMR of fish are robust to repeated forays into warmer environments, MMR displays plasticity, allowing fish to be less constrained aerobically in cold water after briefly occupying warmer waters.

Item Type:Articles
Additional Information:This work was funded by Fisheries and Oceans Canada, Species-at-Risk program; a Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant (J.R.T.; grant no. 418503); an NSERC Canada Graduate Scholarship (M.M.G.), and a W. Garfield Weston Foundation award in Northern Research (M.M.G.). J.R.T. is the Canada Research Chair in Environment Dynamics and Metabolism (grant no. 223744).
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Killen, Professor Shaun
Authors: Guzzo, M. M., Mochnacz, N. J., Durhack, T., Kissinger, B. C., Killen, S. S., and Treberg, J. R.
College/School:College of Medical Veterinary and Life Sciences > Institute of Biodiversity Animal Health and Comparative Medicine
Journal Name:Journal of Experimental Biology
Publisher:Company of Biologists
ISSN:0022-0949
ISSN (Online):1477-9145
Published Online:16 May 2019
Copyright Holders:Copyright © 2019 The Company of Biologists Ltd
First Published:First published in Journal of Experimental Biology 222:jeb198143
Publisher Policy:Reproduced in accordance with the copyright policy of the publisher

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