Divergent field metabolic rates highlight the challenges of increasing temperatures and energy limitation in aquatic ectotherms

Karissa O. Lear, David L. Morgan, Jeff M. Whitty, Nicholas M. Whitney, Evan E. Byrnes, Stephen J. Beatty, Adrian C. Gleiss

Research output: Contribution to journalArticlepeer-review

3 Scopus citations

Abstract

Environments where extreme temperatures and low productivity occur introduce energetically challenging circumstances that may be exacerbated by climate change. Despite the strong link between metabolism and temperature in ectotherms, there is a paucity of data regarding how the metabolic ecology of species affects growth and fitness under such circumstances. Here, we integrated data describing field metabolic rates and body condition of two sympatric species of ectotherms with divergent lifestyles, the benthic freshwater (or largetooth) sawfish (Pristis pristis) and the epipelagic bull shark (Carcharhinus leucas) occurring in the Fitzroy River, Western Australia, to test the implications of their differing metabolic ecologies for vulnerability to rising temperatures. Over a temperature range of 18–34 °C, sawfish had lower field metabolic rates (63–187 mg O2 kg−0.86 h−1) and lower temperature sensitivity of metabolic rates [activation energy (EA) = 0.35 eV] than bull sharks (187–506 mg O2 kg−0.86 h−1; EA = 0.48 eV). Both species lost body mass throughout the dry season, although bull sharks significantly more (0.17% mass loss day−1) than sawfish (0.07% mass loss day−1). Subsequent bioenergetics modelling showed that under future climate change scenarios, both species would reach potentially lethal levels of mass loss during dry season periods before the end of the century. These results suggest that ectotherms with low metabolic rates may be better suited to extreme environmental conditions, and that even small increases in temperature due to climate change could have substantial impacts on the ability of ectotherms to grow and survive in harsh conditions, including high temperatures and energy-limiting circumstances.

Original languageEnglish (US)
Pages (from-to)311-323
Number of pages13
JournalOecologia
Volume193
Issue number2
DOIs
StatePublished - Jun 1 2020
Externally publishedYes

Bibliographical note

Funding Information:
We are greatly appreciative of support and assistance with fieldwork from the Nyikina-Mangala Rangers over many years, as well as a number of volunteers including T. Fazeldean, J. R. Albert, J. Keleher, T. Campbell, H. Ashe, and G. Teasdale. Captive respirometry work and husbandry of sawfish was conducted with substantial assistance, guidance, and hospitality from North Regional TAFE Aquaculture Centre staff, including S. Bennett, A. Aris, M. Williams, and J. Cooper. We also gratefully acknowledge support of our Kimberley field base from J. and G. Kelly. We would also like to thank two anonymous referees and J. Rummer, Y. Papastamatiou, and E. Thorstad for providing feedback and revisions that have greatly improved this manuscript. This project was funded by many sources including Murdoch University Strategic Research Fund, the Australian Research Council (project 150100321), Forrest Research Foundation, Holsworth Wildlife Research Fund, Fisheries Society of the British Isles, Australia Pacific Science Foundation, Waitt Foundation, and Graduate Women Western Australia. K. Lear was supported by an Australian Government Research Training Program Scholarship and the Forrest Research Foundation.

Funding Information:
We are greatly appreciative of support and assistance with fieldwork from the Nyikina-Mangala Rangers over many years, as well as a number of volunteers including T. Fazeldean, J. R. Albert, J. Keleher, T. Campbell, H. Ashe, and G. Teasdale. Captive respirometry work and husbandry of sawfish was conducted with substantial assistance, guidance, and hospitality from North Regional TAFE Aquaculture Centre staff, including S. Bennett, A. Aris, M. Williams, and J. Cooper. We also gratefully acknowledge support of our Kimberley field base from J. and G. Kelly. We would also like to thank two anonymous referees and J. Rummer, Y. Papastamatiou, and E. Thorstad for providing feedback and revisions that have greatly improved this manuscript. This project was funded by many sources including Murdoch University Strategic Research Fund, the Australian Research Council (project 150100321), Forrest Research Foundation, Holsworth Wildlife Research Fund, Fisheries Society of the British Isles, Australia Pacific Science Foundation, Waitt Foundation, and Graduate Women Western Australia. K. Lear was supported by an Australian Government Research Training Program Scholarship and the Forrest Research Foundation.

Publisher Copyright:
© 2020, Springer-Verlag GmbH Germany, part of Springer Nature.

Keywords

  • Accelerometer
  • Bioenergetics
  • Biologging
  • Climate change
  • Growth
  • Respirometry

PubMed: MeSH publication types

  • Journal Article

Fingerprint

Dive into the research topics of 'Divergent field metabolic rates highlight the challenges of increasing temperatures and energy limitation in aquatic ectotherms'. Together they form a unique fingerprint.

Cite this