Dolphins, humans both benefit from fishing collaboration

A fishing community in southern Brazil has an unusual ally: wild dolphins.

Accounts of people and dolphins working together to hunt fish go back millennia, from the time of the Roman Empire near what is now southern France to 19th century Queensland, Australia. But while historians and storytellers have recounted the human point of view, it's been impossible to confirm how the dolphins have benefited — or if they've been taken advantage of — before sonar and underwater microphones could track them underwater.

In the seaside city of Laguna, scientists have, for the first time, used drones, underwater sound recordings and other tools to document how local people and dolphins coordinate actions and benefit from each other’s labor. The most successful humans and dolphins are skilled at reading each other's body language. The research was published Monday in the journal Proceedings of the National Academy of Sciences.

The Laguna residents work with wild bottlenose dolphins to catch schools of migratory silver fish called mullet. It’s a locally famous alliance that has been recorded in newspaper records going back 150 years.

“This study clearly shows that both dolphins and humans are paying attention to each other’s behavior, and that dolphins provide a cue to when the nets should be cast,” said Stephanie King, a biologist who studies dolphin communication at the University of Bristol and was not involved in the research.

“This is really incredible cooperative behavior,” she added. “By working with the dolphins," the people catch more fish, "and the dolphins are more successful in foraging, too.”

Dolphins and humans are both highly intelligent and long-lived social animals. But when it comes to fishing, they have different abilities.

“The water is really murky here, so the...