Effects of elevated CO2 on fish behaviour undiminished by transgenerational acclimation

Behaviour and sensory performance of marine fishes are impaired at CO2 levels: projected in occur in the ocean in the next 50-100 years(1-5), and there is limited potential for within-generation acclimation to elevated CO2 (refs 6,7). However, whether fish behaviour can acclimate or adapt to elevated CO2 over multiple generations remains unanswerei.L We tested for transgenerational acclimation of reef fish olfactory preferences and behavioural lateralization at moderate (656 mu atm) and high (912 mu atm) end-of-century CO2 projections. Juvenile spiny damselfish, Acanthochromis polyacanthus, from control parents (446 mu atm) exhibited an innate avoidance to alarm cue (CAC) when reared in control conditions. in contrast:. lost their innate avoidance of CAC and even became str ongly attracted to CAC when reared at elevated CO2 levels from parents maintained at mid-CO2 and high-CO2 levels also lost their innate avoidance of CAC when reared in elevated CO2, demonstrating no capacity for Ira generational FiccInntion of olfactory responses. Behavioural lateralization was also disrupted for juveniles reared under elevated CO2, regardless of parental conditioning. Our results show minimal potential for transgenerationol acclimation in this fish, suggesting that genetic adaptation will be necessary to overcome the effects of ocean acidification on behaviour.