Physiological Challenges to Fishes in a Warmer and Acidified Future

With the projected levels of global warming and ocean acidification, fishes have to face warmer waters with CO 2 levels that are the highest in over 30 million years. The resultant rise in body temperature means that metabolic rates of fish will increase, and some may become energetically compromised. No less worrying, and maybe more surprising, is that rising CO 2 concentrations appear to trigger pH regulatory mechanisms that disrupts neural ion gradients, leading to altered neurotransmitter function and maladaptive behavioral changes. We point out the many outstanding questions, including the ultimate one: Will fish be able to adapt to these challenges?