Chronic environmental warming alters cardiovascular and haematological stress responses in European perch (Perca fluviatilis).
Environmental warming and acute stress increase cardiorespiratory activity in ectothermic animals like fish. While thermal acclimation can buffer the direct thermal effects on basal cardiorespiratory function during chronic warming, little is known about how acclimation affects stress-induced cardiorespiratory responses. We compared cardiovascular and haematological responses to chasing stress in cannulated wild European perch (Perca fluviatilis) from a reference area at natural temperature (16 °C) with perch from the 'Biotest enclosure'; an experimental system chronically warmed (22 °C) by effluents from a nuclear power plant. Routine blood pressure was similar, but Biotest perch had slightly higher resting heart rate (59.9 ± 2.8 vs 51.3 ± 2.9 beats min-1), although the Q10for heart rate was 1.3, indicating pronounced thermal compensation. Chasing stress caused hypertension and a delayed tachycardia in both groups, but the maximum heart rate increase was 2.5-fold greater in Biotest fish (43.3 ± 4.3 vs 16.9 ± 2.7 beats min-1). Moreover, the pulse pressure response after stress was greater in reference fish, possibly due to the less pronounced tachycardia or a greater ventricular pressure generating capacity and thermally mediated differences in aortic compliance. Baseline haematological status was also similar, but after chasing stress, the haematocrit was higher in Biotest fish due to exacerbated red blood cell swelling. This study highlights that while eurythermal fishes can greatly compensate routine cardiorespiratory functions through acclimation processes, stress-induced responses may still differ markedly. This knowledge is essential when utilising cardiorespiratory variables to quantify and compare stress responses across environmental temperatures, and to forecast energetic costs and physiological constraints in ectothermic animals under global warming.
Department of Biological and Environmental Sciences, University of Gothenburg, Box 463, 405 30, Gothenburg, Sweden.
Andreas
A
Ekström
Department of Biology, Norwegian University of Science and Technology, Trondheim, Norway.
Fredrik
F
Jutfelt
Biology Education Centre, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden.
L
L
Fredrik Sundström
Department of Aquatic resources, Institute of Coastal Research, Swedish University of Agricultural Sciences, Öregrund, Sweden.
Anders
A
Adill
Department of Aquatic resources, Institute of Coastal Research, Swedish University of Agricultural Sciences, Öregrund, Sweden.
Teija
T
Aho
Department of Biological and Environmental Sciences, University of Gothenburg, Box 463, 405 30, Gothenburg, Sweden. erik.sandblom@bioenv.gu.se.
Erik
E
Sandblom
D000064:Acclimatization / Q000502:physiology; D000818:Animals; D001794:Blood Pressure / Q000502:physiology; D002320:Cardiovascular Physiological Phenomena; D029941:Fish Proteins / Q000378:metabolism; D057232:Global Warming; D006339:Heart Rate / Q000502:physiology*; D006400:Hematocrit; D006454:Hemoglobins / Q000378:metabolism; D010471:Perches / Q000502:physiology*; D013312:Stress, Physiological / Q000502:physiology*; D013696:Temperature
D029941:Fish Proteins; D006454:Hemoglobins
Blood pressure; Cardiovascular; Fish; Haematology; Heart rate; Stress response; Temperature acclimation