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Research article - Peer-reviewed, 2016

Cardiac oxygen limitation during an acute thermal challenge in the European perch: effects of chronic environmental warming and experimental hyperoxia

Ekström, Andreas; Brijs, Jeroen; Clark, Timothy D.; Gräns, Albin; Jutfelt, Fredrik; Sandblom, Erik


Oxygen supply to the heart has been hypothesized to limit cardiac performance and whole animal acute thermal tolerance (CTmax) in fish. We tested these hypotheses by continuously measuring venous oxygen tension (PvO(2)) and cardiovascular variables in vivo during acute warming in European perch (Perca fluviatilis) from a reference area during summer (18 degrees C) and a chronically heated area (Biotest enclosure) that receives warm effluent water from a nuclear power plant and is normally 5-10 degrees C above ambient (24 degrees C at the time of experiments). While CTmax was 2.2 degrees C higher in Biotest compared with reference perch, the peaks in cardiac output and heart rate prior to CTmax occurred at statistically similar PvO(2) values (2.3-4.0 kPa), suggesting that cardiac failure occurred at a common critical PvO(2) threshold. Environmental hyperoxia (200% air saturation) increased PvO(2) across temperatures in reference fish, but heart rate still declined at a similar temperature. CTmax of reference fish increased slightly (by 0.9 degrees C) in hyperoxia, but remained significantly lower than in Biotest fish despite an improved cardiac output due to an elevated stroke volume. Thus, while cardiac oxygen supply appears critical to elevate stroke volume at high temperatures, oxygen limitation may not explain the bradycardia and arrhythmia that occur prior to CTmax. Acute thermal tolerance and its thermal plasticity can, therefore, only be partially attributed to cardiac failure from myocardial oxygen limitations, and likely involves limiting factors on multiple organizational levels.


cardiac performance; myocardial oxygenation; PvO(2) threshold; thermal acclimation; teleost

Published in

AJP - Regulatory, Integrative and Comparative Physiology
2016, volume: 311, number: 2, pages: R440-R449

Authors' information

Ekström, Andreas
University of Gothenburg
Brijs, Jeroen
University of Gothenburg
Clark, Timothy D.
Australian Institute of Marine Science (AIMS)
Swedish University of Agricultural Sciences, Department of Animal Environment and Health
Jutfelt, Fredrik
University of Gothenburg
Sandblom, Erik
University of Gothenburg

Sustainable Development Goals

SDG14 Life below water

UKÄ Subject classification

Climate Research

Publication Identifiers


URI (permanent link to this page)