Future shock: ocean acidification and seasonal water temperatures alter the physiology of competing temperate and coral reef fishes


  • Temperate and coral reef fishes were exposed to ocean acidification and ocean warming
  • Coral reef fish decreased physiological performance in future winters (20 °C + OA)
  • Coral reef fish increased lipid energy storage in future winter conditions
  • Temperate fish increased oxidative damage in future summers (26 °C + OA)
  • Future climate can modify the physiology of temperate and coral fishes seasonally


Climate change can directly (physiology) and indirectly (novel species interactions) modify species responses to novel environmental conditions during the initial stages of range shifts. Whilst the effects of climate warming on tropical species at their cold-water leading ranges are well-established, it remains unclear how future seasonal temperature changes, ocean acidification, and novel species interactions will alter the physiology of range-shifting tropical and competing temperate fish in recipient ecosystems. Here we used a laboratory experiment to examine how ocean acidification, future summer vs winter temperatures, and novel species interactions could affect the physiology of competing temperate and range-extending coral reef fish to determine potential range extension outcomes. In future winters (20 °C + ocean acidification) coral reef fish at their cold-water leading edges showed reduced physiological performance (lower body condition and cellular defence, and higher oxidative damage) compared to present-day summer (23 °C + control pCO2) and future summer conditions (26 °C + ocean acidification). However, they showed a compensatory effect in future winters through increased long-term energy storage. Contrastingly, co-shoaling temperate fish showed higher oxidative damage, and reduced short-term energy storage and cellular defence in future summer than in future winter conditions at their warm-trailing edges. However, temperate fish benefitted from novel shoaling interactions and showed higher body condition and short-term energy storage when shoaling with coral reef fish compared to same-species shoaling. We conclude that whilst during future summers, ocean warming will likely benefit coral reef fishes extending their ranges, future winter conditions may still reduce coral reef fish physiological functioning, and may therefore slow their establishment at higher latitudes. In contrast, temperate fish species benefit from co-shoaling with smaller-sized tropical fishes, but this benefit may dissipate due to their reduced physiological functioning under future summer temperatures and increasing body sizes of co-shoaling tropical species.

Mitchell A., Hayes C., Booth D. J. & Nagelkerken I., 2023. Future shock: ocean acidification and seasonal water temperatures alter the physiology of competing temperate and coral reef fishes. Science of the Total Environment: 163684. doi: 10.1016/j.scitotenv.2023.163684. Article.

  • Reset


OA-ICC Highlights

%d bloggers like this: