Brain cooling marginally increases acute upper thermal tolerance in Atlantic cod

Fredrik Jutfelt*, Dominique G Roche, Timothy D Clark, Tommy Norin, Sandra A Binning, Ben Speers-Roesch, Mirjam Amcoff, Rachael Morgan, Anna H Andreassen, Josefin Sundin

*Corresponding author for this work

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Abstract

Physiological mechanisms determining thermal limits in fishes are debated but remain elusive. It has been hypothesised that motor function loss, observed as loss of equilibrium during acute warming, is due to direct thermal effects on brain neuronal function. To test this, we mounted cooling plates on the heads of Atlantic cod (Gadus morhua) and quantified whether local brain cooling increased whole-organism acute upper thermal tolerance. Brain cooling reduced brain temperature by 2-6°C below ambient water and increased thermal tolerance by 0.5 and 0.6°C on average relative to instrumented and uninstrumented controls, respectively, suggesting that direct thermal effects on brain neurons may contribute to setting upper thermal limits in fish. However, the improvement in thermal tolerance with brain cooling was small relative to the difference in brain temperature, demonstrating that other mechanisms (e.g., failure of spinal and peripheral neurons, or muscle) may also contribute to controlling acute thermal tolerance.
Original languageEnglish
Article numberjeb208249
JournalJournal of Experimental Biology
Volume222
ISSN0022-0949
DOIs
Publication statusPublished - 2019

Keywords

  • Climate change
  • Fish
  • Global warming
  • Oxygen- and capacity-limited thermal tolerance (OCLTT)
  • Critical thermal maximum (CTmax)
  • Loss of equilibrium (LOE)
  • Thermal ramping

Cite this

Jutfelt, F., Roche, D. G., Clark, T. D., Norin, T., Binning, S. A., Speers-Roesch, B., ... Sundin, J. (2019). Brain cooling marginally increases acute upper thermal tolerance in Atlantic cod. Journal of Experimental Biology, 222, [jeb208249]. https://doi.org/10.1242/jeb.208249