Marine & Environmental Sciences Faculty Proceedings, Presentations, Speeches, Lectures


The Effect of Elevated CO2 on Swimming Performance and Schooling in a Coral Reef Fish Species

Event Name/Location

Society for Experimental Biology Annual Conference / Gothenburg, Sweden

Document Type

Conference Proceeding

Publication Date



Atmospheric carbon dioxide is expected to more than double by the end of the century. The resulting changes in ocean chemistry will affect the behaviour, sensory systems and physiology of many fish species. How these effects may influence the schooling dynamics of gregarious fishes remains poorly understood. In the present study, we examined the influence of elevated CO2 on the swimming performance, maximum aerobic metabolic rate (MMR) and schooling behaviour in the redbelly yellowtail fusilier (Caesio cuning). Schools were acclimated to one of two CO2 treatments: control (400 µatm) or high-CO2 (1000 µatm) for two weeks. Schooling dynamics were tested in a 90L swim tunnel system, at four fixed flow speeds: 15, 30, 45 and 60 cm/s. Trials were video-recorded in three dimensions and analysed for school volume, density and shape, the position preference of each individual and their nearest neighbor distance. Individual swimming performance was assessed in terms of gait transition speed (Up-c ) and critical swimming speed (Ucrit) using a continuous acceleration test. MMR was tested using standard respirometry techniques. While individual swimming performance (Upc and Ucrit) was not impacted by elevated CO2 conditions, schools exhibited altered swimming behaviour, with reduced position shuffling and cohesion under elevated CO2 conditions. These results suggest that the tradeoffs of living in a group could be altered under projected future ocean conditions. Given that schooling behaviour is widespread among fishes as a tool for predator avoidance, these changes could have far-reaching consequences for a range of ecologically and economically important fish species.



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