Does tolerance to fast warming predict tolerance to slow warming in fishes?
Abstract
1. Critical thermal maximum (CTmax) is widely used to quantify upper thermal limits in fishes, but its ecological relevance has been questioned because standard protocols use fast warming rates (0.3°C min-¹; 18°C h-¹) that rarely occur in nature, where thermal stress more typically unfolds over hours to days. Whether CTmax under fast warming predicts warming tolerance to slower, ecologically realistic warming remains a critical question for climate risk assessments and mechanistic species distribution models. 2. We measured thermal tolerance under fast (0.3°C min-¹) and slow (1°C h-¹) warming in the same individuals across seven temperate fish species. This paired design allowed us to estimate individual-level correlations between fast and slow warming tolerance and assess how this relationship varied among species. 3. We observed substantial interspecific variation in the direction of the fast–slow warming tolerance relationship. Slow CTmax was higher than fast CTmax in three-spined stickleback, lesser pipefish, corkwing wrasse, and European eel, while the opposite was true for European plaice, bluegill sunfish, and Atlantic cod. 4. Fast and slow CTmax were only weakly correlated at the individual level, and significant correlations were only detected in two of seven species. However, at the species level, fast and slow CTmax was significantly correlated (R² marginal = 0.873; between-species slope = 1.157). 5. Standard fast-warming CTmax does not consistently predict individual thermal tolerance under slower, more ecologically realistic warming rates and its usage may overlook biologically meaningful species-specific differences in thermal vulnerability. Fast-warming CTmax should be interpreted with caution in the context of ecological forecasting and climate risk assessments as it can over-estimate upper thermal tolerance and should be used at the appropriate biological scale.
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BibTeX
@misc{lechner2026does,
title = {{Does tolerance to fast warming predict tolerance to slow warming in fishes?}},
author = {Emily Lechner and Erin Stewart and Alex Berry and Christian J Bihun and Sandra Ann Binning and Tamzin Blewett and Ivan Cadonic and Timothy D Clark and Zara-Louise Cowan and Jeremy De Bonville and Rasmus Ern and Maryane Gradito and Leon Green and Elizabeth Hoots and Luis Kuchenmüller and Vincent Mélançon and Moa Metz and Leon Pfeufer and Patrice Pottier and Graham D Raby and Dominique Roche and Josefin Sundin and Elena Tamarit-Castro and Mafalda Tomás and Juliane Vigneault and Zacharia Zouhair and Eirik Åsheim and Fredrik Jutfelt},
howpublished = {EcoEvoRxiv},
year = {2026},
month = sep,
doi = {10.32942/x2x11q},
url = {https://ecoevorxiv.org/repository/view/15023/},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Does tolerance to fast warming predict tolerance to slow warming in fishes?
AU - Emily Lechner
AU - Erin Stewart
AU - Alex Berry
AU - Christian J Bihun
AU - Sandra Ann Binning
AU - Tamzin Blewett
AU - Ivan Cadonic
AU - Timothy D Clark
AU - Zara-Louise Cowan
AU - Jeremy De Bonville
AU - Rasmus Ern
AU - Maryane Gradito
AU - Leon Green
AU - Elizabeth Hoots
AU - Luis Kuchenmüller
AU - Vincent Mélançon
AU - Moa Metz
AU - Leon Pfeufer
AU - Patrice Pottier
AU - Graham D Raby
AU - Dominique Roche
AU - Josefin Sundin
AU - Elena Tamarit-Castro
AU - Mafalda Tomás
AU - Juliane Vigneault
AU - Zacharia Zouhair
AU - Eirik Åsheim
AU - Fredrik Jutfelt
PY - 2026
DA - 2026/09/16
PB - EcoEvoRxiv
DO - 10.32942/x2x11q
UR - https://ecoevorxiv.org/repository/view/15023/
AB - 1. Critical thermal maximum (CTmax) is widely used to quantify upper thermal limits in fishes, but its ecological relevance has been questioned because standard protocols use fast warming rates (0.3°C min-¹; 18°C h-¹) that rarely occur in nature, where thermal stress more typically unfolds over hours to days. Whether CTmax under fast warming predicts warming tolerance to slower, ecologically realistic warming remains a critical question for climate risk assessments and mechanistic species distribution models. 2. We measured thermal tolerance under fast (0.3°C min-¹) and slow (1°C h-¹) warming in the same individuals across seven temperate fish species. This paired design allowed us to estimate individual-level correlations between fast and slow warming tolerance and assess how this relationship varied among species. 3. We observed substantial interspecific variation in the direction of the fast–slow warming tolerance relationship. Slow CTmax was higher than fast CTmax in three-spined stickleback, lesser pipefish, corkwing wrasse, and European eel, while the opposite was true for European plaice, bluegill sunfish, and Atlantic cod. 4. Fast and slow CTmax were only weakly correlated at the individual level, and significant correlations were only detected in two of seven species. However, at the species level, fast and slow CTmax was significantly correlated (R² marginal = 0.873; between-species slope = 1.157). 5. Standard fast-warming CTmax does not consistently predict individual thermal tolerance under slower, more ecologically realistic warming rates and its usage may overlook biologically meaningful species-specific differences in thermal vulnerability. Fast-warming CTmax should be interpreted with caution in the context of ecological forecasting and climate risk assessments as it can over-estimate upper thermal tolerance and should be used at the appropriate biological scale.
ER -