title: Experimental manipulations of tissue oxygen supply do not affect warming tolerance of European perch.
abstract: A progressive inability of the cardiorespiratory system to maintain systemic oxygen supply at elevated temperatures has been suggested to reduce aerobic scope and the upper thermal limit of aquatic ectotherms. However, few studies have directly investigated the dependence of thermal limits on oxygen transport capacity. By manipulating oxygen availability (via environmental hyperoxia) and blood oxygen carrying capacity (via experimentally induced anaemia) in European perch (Perca fluviatilis Linneaus), we investigated the effects of oxygen transport capacity on aerobic scope and the critical thermal maximum (CT(max)). Hyperoxia resulted in a twofold increase in aerobic scope at the control temperature of 23°C, but this did not translate to an elevated CT(max) in comparison with control fish (34.6±0.1 versus 34.0±0.5°C, respectively). Anaemia (∼43% reduction in haemoglobin concentration) did not cause a reduction in aerobic scope or CT(max) (33.8±0.3°C) compared with control fish. Additionally, oxygen consumption rates of anaemic perch during thermal ramping increased in a similar exponential manner to that in control fish, highlighting that perch have an impressive capacity to compensate for a substantial reduction in blood oxygen carrying capacity. Taken together, these results indicate that oxygen limitation is not a universal mechanism determining the CT(max) of fishes.
authors.affiliation: Department of Biological and Environmental Sciences, University of Gothenburg, SE-405 30 Gothenburg, Sweden jeroen.brijs@bioenv.gu.se.
authors.forename: Jeroen
authors.initials: J
authors.lastname: Brijs
authors.affiliation: Department of Biological and Environmental Sciences, University of Gothenburg, SE-405 30 Gothenburg, Sweden.
authors.forename: Fredrik
authors.initials: F
authors.lastname: Jutfelt
authors.affiliation: Australian Institute of Marine Science, Townsville 4810, Queensland, Australia.
authors.forename: Timothy D
authors.initials: TD
authors.lastname: Clark
authors.affiliation: Department of Animal Environment and Health, Swedish University of Agricultural Sciences, SE-532 23 Skara, Sweden.
authors.forename: Albin
authors.initials: A
authors.lastname: Gräns
authors.affiliation: Department of Biological and Environmental Sciences, University of Gothenburg, SE-405 30 Gothenburg, Sweden.
authors.forename: Andreas
authors.initials: A
authors.lastname: Ekström
authors.affiliation: Department of Biological and Environmental Sciences, University of Gothenburg, SE-405 30 Gothenburg, Sweden.
authors.forename: Erik
authors.initials: E
authors.lastname: Sandblom
mesh_terms: D000332:Aerobiosis; D000740:Anemia; D000818:Animals; D001481:Basal Metabolism; D006454:Hemoglobins / Q000378:metabolism; D006358:Hot Temperature; D010100:Oxygen / Q000378:metabolism*; D010101:Oxygen Consumption; D010471:Perches / Q000502:physiology*
chemical_list: D006454:Hemoglobins; D010100:Oxygen
keywords: Aerobic scope; Anaemia; Hyperoxia; Metabolism; Oxygen consumption; Temperature