Will Global Warming Make Fish Stupid?

There’s already evidence that rapidly warming oceans are harming fish. The acidification of the water—something that happens as the seas absorb human-produced carbon dioxide—is thought to make certain species anxious and prone to hiding, and even destroy their ability to recognize each other.

Now there are indications it could turn them dangerously dumb, too. When exposed to raised CO2 levels, spiny damselfish seem to be unable to sense signs of danger emitted by their fellow damselfish, according to a study in Scientific Reports. That’s bad news, because if a predator is roaming the reefs chomping on fish, an entire micropopulation is in effect twiddling its fins waiting to be eaten.