Paper Reviewed
Maneja, R.H., Frommel, A.Y., Browman, H.I., Geffen, A.J., Folkvord, A., Piatkowski, U., Durif, C.M.F., Bjelland, R., Skiftesvik, A.B. and Clemmesen, C. 2015. The swimming kinematics and foraging behavior of larval Atlantic herring (Clupea harengus L.) are unaffected by elevated pCO2. Journal of Experimental Marine Biology and Ecology 466: 42-48.

It is speculated, in the words of Maneja et al. (2015) that "ocean acidification might increase mortality in marine fish larvae through, for example, effects on their behavior that make them more susceptible to predation, reduce their food intake, or alter their orientation towards nursery grounds." And, therefore, they decided to explore this possibility in larvae of Atlantic herring, which they say is "an important commercial fish species in the North Atlantic."

In more specific terms, the ten researchers say "the kinematics of swimming behavior of Atlantic herring larvae cultured under three pCO2 conditions (control - 370, medium - 1800, and high - 4200 µatm) were extracted at 34 days post-hatch (dph) from swim path recordings obtained using silhouette video photography," after which "the swim paths were analyzed for move duration, speed and length, stop duration, and horizontal and vertical turn angles to determine the effects of elevated pCO2 on fish larval behavior." And what did they thereby learn?

In brief response, Maneja et al. write that the swimming kinematics in Atlantic herring larvae that had survived to 34-dph were "unaffected by extremely elevated levels of seawater pCO2, indicating that at least some larvae in the population are resilient to ocean acidification." And in further commenting on their findings, they say "it also appears that inter-individual variation in the behavioral responses of some fishes to elevated pCO2 selects for tolerant individuals, possibly resulting in resilience to ocean acidification," citing the work of Munday et al. (2012).

And so it would appear that Atlantic herring larvae may well be able to tolerate the degree of ocean acidification induced by an atmospheric CO2 concentration fully 4.5 times greater than that of today.

Reference
Munday, P.L., McCormick, M.I., Meekan, M., Dixson, D.L., Watson, S.-A., Chivers, D.P. and Ferrari, M.C.O. 2012. Selective mortality associated with variation in CO2 tolerance in a marine fish. Ocean Acidification 1: 1-5.