In Laguna, Brazil, the local fishermen rely on dolphins to help them with their yearly fish catch.
“About 200 local artisanal fishermen are almost entirely reliant on the dolphins for catching their fish,” study researcher Fábio Daura-Jorge, of the Federal University of Santa Catarina, in Brazil, wrote in a statement sent to LiveScience. “The fishermen do not fish without the assistance of the dolphins and know the individual animals from their natural marks and can recognize them by eye.”
Scientists had known that dolphins work together to herd groups of mullet, a fish that’s an important source of food for local fishermen, toward a line of fishermen in boats or knee-deep water. Then the dolphins signal with specialized head or tail slaps when and where the fishermen should throw their nets. The cooperation is helpful to both parties, researchers said. The two wouldn’t survive without each other.
On a stretch of the Ayeyarwady river, also known as the Irrawaddy river, near Myanmar’s Mandalay, fishermen from six villages work hand-in-fin with 26 Irrawaddy dolphins in a unique collaboration. Taught to do so since childhood, the fishermen cooperatively fish the river with the assistance of the dolphins. The tradition, origin unknown, is said to have been in practice since the 1860s.
The fishermen summon the dolphins by tapping a pointed stick on the side of their wooden boats while making a cooing sound. The dolphins herd fish in the surrounding waters towards the boat. A wave of their tails above the water signals to the fishermen that it is time for the net to be cast. When practising this cooperative fishing technique, the fishermen are said to be able to catch six times more fish than when done individually. The dolphins also benefit from the easy catch of fish that escape the net.