Ocean Acidification Has No Effect on the Early Life Stages of Atlantic Cod (Gadus morhua L.) or Atlantic Herring (Clupea harengus L.), Nor on Their Copepod Prey (Calanus finmarchicus)

Kinematics of swimming, foraging behavior, and global proteome expression of larval Atlantic cod and Atlantic herring cultured under pCO₂ conditions predicted to occur 100-200 years from now were studied. The swimming kinematics (moves; turns; stops; activity; swim speeds) and foraging (prey attack postures) of these larvae were highly resilient to elevated pCO2 levels. The proteome structure of the larvae was similarly unaffected, suggesting that larvae can cope with projected levels of pCO₂ without significant proteome-wide changes. Calanus finmarchicus, the nauplii of which are prey for these fish larvae, displayed normal respiration rates, feeding, swimming and predator avoidance behaviors under elevated pCO₂ conditions. We conclude that these fish larvae, and their interactions with their main copepod prey, will not be significantly affected by ocean acidification alone. Although the conclusion that the larvae will be unaffected by ocean acidification appears inconsistent with other work on these and other species, we propose that this is due to the nature of the end points measured in acute experiments such as these.