Zebrafish (Danio rerio) behaviour is largely unaffected by elevated pCO(2)

Ocean acidification, the decrease in ocean pH caused by anthropogenic emission of carbon dioxide, can cause behavioural disturbances in marine teleost species. We investigated whether AB-strain zebrafish (Danio rerio) show similar behavioural disturbances in the presence of elevated CO(2), because this model species could open up a toolbox to investigate the physiological and neurological mechanisms of CO(2) exposure. We found no effect of elevated CO(2) (~1600 μatm) on the behaviour of zebrafish in the open field test, indicating that zebrafish are largely insensitive to this elevated CO(2) level. In the detour test of lateralization, however, zebrafish exposed to elevated CO(2) swam more often to the right, whereas individuals exposed to control CO(2) (~400 μatm) had no preference for left or right. This may indicate that some behaviours of some freshwater fishes can be altered by elevated CO(2) levels. Given that elevated CO(2) levels often occur in recirculating aquaculture and aquarium systems, we recommend that dissolved CO(2) levels are measured and, if necessary, the aquarium water should be aerated, in order to exclude CO(2) level as a confounding factor in experiments.