Dolphins And Humans Can Work Together, Oregon State Researchers Say
Newport, Ore. – For fifteen years off the southern coast of Brazil, in the city of Laguna, Oregon State University researchers have been observing the patterns of bottlenose dolphins and the local artisanal fisherman to study how communication between the two led to both of them catching more fish. “A rare example of an interaction by two top predators that is beneficial to both parties,” according to a press release from the school.
Using drones, underwater sonar cameras and microphones, researchers at OSU, alongside Fábio Daura-Jorge of the Universidade Federal de Santa Catarina in Brazil and Damien Farine of the University of Zurich and the Australian National University studied this more than a century old cultural tradition.
“We found that there’s a very fine behavior synchrony that needs to happen between the dolphins actions and the fishers’ reactions, and then both of them will have more fishing success. The dolphins approach and giving a specific behavior cue that fishers interpret as the right time to cast their net, also benefitting the dolphins” said Mauricio Cantor of Oregon State University’s Marine Mammal Institute.
There’s long-term benefits for both parties to this practice as well. “Dolphins that interact with the fishers are 13% more likely to survive to adulthood,” added Cantor, who led the study. There’s also a spiritual connection between the fishers involved and is a major reason why the practice is being considered for a cultural heritage designation in Brazil. “They gain a sense of belonging to the place, cultural pride, on top of the improved socioeconomics.”
But due to illegal fishing in the region, many of the dolphins within this population have begun to die, and fewer and fewer are learning this rare practice. Now it’s at risk of seizing to exist. Their models show that if things keep going the way they are right now the relationship could end.
With that, by learning how the interaction works, researchers took the first step in the conservation process. Now they need to come up with ways for the fishers to continue the practice so the dolphins proceed to learn and pass the knowledge down.
“On the human side this is a bit more manageable. We can work directly with fishers by incentivizing them by putting a premium price on a fish that the fishers catch with the dolphins to increase the likelihood that they will keep partaking in it,” Cantor said. “On the dolphins side, we need to try and reduce the other sources of mortality in the area like the illegal fisheries taking place. Gill nets catch anything including dolphins and are a big source of mortality. And in the past year they have been killing some of the dolphins with the knowledge of the cultural practice.”
Farine said in a statement “this makes this system of substantial scientific interest, as it can help us to understand under what conditions cooperation can evolve and – of growing importance in our rapidly changing world – under what conditions it might go extinct,” and then possibly preserve the practice in other parts of the world where dolphins have been known to work with humans.
“By preserving these cultural behaviors, even on a local scale, we can have an indirect positive effect on the conservation of biological diversity. In this case, if we preserve that traditional practice between humans and dolphins, we also indirectly preserve the diversity of the dolphins, the fish they consume and so on,” Cantor said.
Overall, Cantor says it’s a really cool instance where humans aren’t getting all of the benefits of interacting with nature.
“I see cases like this, rare mutually beneficial interactions between humans and wildlife to be very inspiring. It provides a good illustration of how our interaction with the natural world could be,” Cantor added. “It’s some good news to compare to the lots of bad news that we see everyday regarding environmental crisis.”
Cantor concluded “the cultural value and the biological diversity are important, and it’s important to preserve it.”