Beaver State News

By working together, dolphins and net-casting fishers in Brazil each catch more fish, a rare example of an interaction by two top predators that is beneficial to both parties, researchers have concluded following 15 years of study of the practice.

“We knew that the fishers were observing the dolphins’ behavior to determine when to cast their nets, but we didn’t know if the dolphins were actively coordinating their behavior with the fishers,” said Mauricio Cantor of Oregon State University’s Marine Mammal Institute, who led the study.

“Using drones and underwater imaging, we could observe the behaviors of fishers and dolphins with unprecedented detail and found that they catch more fish by working in synchrony,” said Cantor, an assistant professor in OSU’s College of Agricultural Sciences. “This shows that this is a mutually beneficial interaction between the humans and the dolphins.”

The researchers’ findings were just published in the Proceedings of the National Academy of Sciences. Co-authors of the paper are Professor Fábio Daura-Jorge of the Universidade Federal de Santa Catarina in Brazil and Professor Damien Farine of the University of Zurich and the Australian National University.

Synchronized movements of flocks of birds and schools of fish are a common yet striking behavior that can be key to the animals’ survival. Synchronized behavior between species, like that between the Lahille’s bottlenose dolphins and the traditional net-casting fishers in Brazil, is much more rare.

The practice is considered a cultural tradition in the city of Laguna on Brazil’s southern coast, where it occurred for more than 140 years and has been passed down through generations of fishers and dolphins. The cooperative fishing relationship is specific to this population of dolphins and is not a genetic trait in the animals, Cantor said.

Original source can be found here