Short-term acclimation dynamics in a coldwater fish

Erin M C Stewart; Vince R Frasca; Chris C Wilson; Graham D Raby

doi:10.1016/j.jtherbio.2023.103482

Short-term acclimation dynamics in a coldwater fish

J Therm Biol. 2023 Feb:112:103482. doi: 10.1016/j.jtherbio.2023.103482. Epub 2023 Jan 14.

Authors

Erin M C Stewart¹, Vince R Frasca², Chris C Wilson³, Graham D Raby⁴

Affiliations

¹ Environmental and Life Sciences Graduate Program, Trent University, Peterborough, ON, K9J 5G7, Canada. Electronic address: erinstewart@trentu.ca.
² Ontario Ministry of Natural Resources and Forestry, Aquatic Research and Monitoring Section, Codrington Fisheries Research Facility, Codrington, ON, K0K 1R0, Canada.
³ Ontario Ministry of Natural Resources and Forestry, Aquatic Research and Monitoring Section, Trent University, Peterborough, ON, K9J 7B8, Canada.
⁴ Department of Biology, Trent University, Peterborough, ON, K9J 1Z8, Canada.

PMID: 36796924
DOI: 10.1016/j.jtherbio.2023.103482

Abstract

Critical thermal maximum (CT_max) is widely used for measuring thermal tolerance but the strong effect of acclimation on CT_max is a likely source of variation within and among studies/species that makes comparisons more difficult. There have been surprisingly few studies focused on quantifying how quickly acclimation occurs or that combine temperature and duration effects. We studied the effects of absolute temperature difference and duration of acclimation on CT_max of brook trout (Salvelinus fontinalis), a well-studied species in the thermal biology literature, under laboratory conditions to determine how each of the two factors and their combined effects influence critical thermal maximum. Using an ecologically-relevant range of temperatures and testing CT_max multiple times between one and 30 days, we found that both temperature and duration of acclimation had strong effects on CT_max. As predicted, fish that were exposed to warmer temperatures longer had increased CT_max, but full acclimation (i.e., a plateau in CT_max) did not occur by day 30. Therefore, our study provides useful context for thermal biologists by demonstrating that the CT_max of fish can continue to acclimate to a new temperature for at least 30 days. We recommend that this be considered in future studies measuring thermal tolerance that intend to have their organisms fully acclimated to a given temperature. Our results also support using detailed thermal acclimation information to reduce uncertainty caused by local or seasonal acclimation effects and to improve the use of CT_max data for fundamental research and conservation planning.

Keywords: Climate change; Incipient lethal temperature; LT50; Plasticity; Salmonid; Thermal tolerance; Thermal variation.

MeSH terms

Acclimatization*
Animals
Fishes*
Temperature