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Mean reef fish body size decreases in warmer waters
  • +4
  • Amy Coghlan,
  • Julia Blanchard,
  • Simon Wotherspoon,
  • Rick Stuart-Smith,
  • Graham Edgar,
  • Neville Barrett,
  • Asta Audzijonyte
Amy Coghlan
University of Tasmania

Corresponding Author:[email protected]

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Julia Blanchard
University of Tasmania
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Simon Wotherspoon
Australian Antarctic Division
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Rick Stuart-Smith
University of Tasmania
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Graham Edgar
University of Tasmania
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Neville Barrett
University of Tasmania
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Asta Audzijonyte
University of Tasmania
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Abstract

Aquatic ectotherms often attain smaller body sizes at higher temperatures. By analysing ~15,000 coastal-reef fish surveys across a 15oC spatial sea surface temperature (SST) gradient, we found that the mean length of fish length in communities decreases by ~5% for each 1oC temperature increase across space. This equated to a 50% decrease in mean length from 14 to 29oC mean annual SST. We found that trophic guild composition shifts from domination by herbivores and planktivores in the tropics, to invertivores and piscivores in cooler waters. By investigating the contribution of trophic composition to community-level mean length, we show ~25% of temperature-related changes could be attributed to trophic composition at the warmest sites, but <1% at colder temperatures. Our findings suggest that small changes in temperature will lead to large changes in fish community body sizes, driven both by community trophic composition in warm waters and mean sizes within trophic guilds.
02 Nov 2023Submitted to Ecology Letters
02 Nov 2023Submission Checks Completed
02 Nov 2023Assigned to Editor
02 Nov 2023Review(s) Completed, Editorial Evaluation Pending
02 Nov 2023Reviewer(s) Assigned