LOS ANGELES — The ocean’s rising carbon-dioxide levels may cause many coral-reef fish to swim toward the smell of predators rather than away from them — and thus toward likely death, marine ecologists said Tuesday.
The greenhouse gas’ ability to alter fish behavior for the worse points to “unexpected potential impact of elevated carbon dioxide in the oceans,” said Philip Munday, a marine ecologist at James Cook University in Queensland, Australia, who led a study published Tuesday in Proceedings of the National Academy of Sciences.
Many coral-reef fish can smell predators nearby, a key ability, given what an appetizing snack the larval fish make for rock cod, dottybacks and other larger, predatory fish.
“They’re kind of like Hershey’s Kisses. . . . Everybody’s after them,” said Mark Hay, a marine ecologist at the Georgia Institute of Technology.
Normally, larval fish would flee from predator odors. But fish exposed to the highest levels of carbon dioxide in the experiment did not. They even seemed to be attracted to the very odor that should set off their neuronal alarms.
