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Humans and Dolphins: Fishing Buddies

1 Aug 2019

In most places on Earth, dolphins create problems for commercial fishermen. The dolphins can get tangled in fishing nets, destroying the nets and themselves in the process. There is one place, however, where dolphins and humans work together to ensure that they both have plenty of fish to eat. To witness this unusual display of symbiosis, you have to go to Brazil, to the small fishing village of Laguna.


The “botos bon”, or good dolphins help fishermen in Brazil. Source: (newscientist.com)

A FISHING STORY

In Laguna, Brazil, local fishermen wade knee-deep into the ocean, holding their handmade fishing nets at the ready. A pod of local dolphins called the “botos bon” (or “good dolphins”) by the locals, herds schools of mullet, a type of fish that is common in the area, into the shallows for the awaiting fishermen. If the dolphins stopped at this point, it would be astonishing enough, but there is even more to this fishy story. A lot more.

Dolphins signal to the fishermen where to cast their nets. Source: (slate.com)

THE DOLPHINS HAVE TRAINED THE HUMANS

The waters near Laguna can be murky, so the dolphins use their echolocation to “see” the mullet fish. Once they have a group of the fish in place, the dolphins signal to the fishermen to let them know when to throw their nets and where to aim. The signals are complex. Some include tail slaps, others are head movements, and still, others are vocalizations. Over the years, the fishermen have learned to interpret the signals from the dolphins so they know just where to cast their nets.

A symbiotic relationship is when both parties benefit. When dolphins help humans to fish, the only one not benefiting is the fish. Source: (lynnesartandsoul.wordpress.com)

NOT ALL LAGUNA DOLPHINS ARE HELPFUL

Researchers studying the phenomenon of the “good dolphins” of Laguna have determined that not all of the dolphins are benevolent. Of the 55 dolphins that call Laguna their home, only about 20 are “botos bon.” This subpopulation of dolphins, however, pass their fishing skills onto their offspring in the exact same way that human fishermen teach their children: by bringing them along on fishing days to learn the ropes. At any given time, there may be several adolescent dolphins who are fishermen in training.

Cooperative fishing may be an ancient practice in Laguna. Source: (offgridquest.com)

GENERATIONS OF SYMBIOTIC FISHING

This sort of symbiotic, or cooperative, fishing has been going on in Laguna for as long as 120 years, perhaps longer. In a letter dating back to the late 1800s, the writer makes reference to it, but historians and anthropologists think that the relationship between man and dolphin goes back much further. They do not know, however, how or why this cooperative arrangement started. It is not known if the dolphins or the humans initiated the arrangement or how they were able to communicate their intentions to each other, so we’re going to assume it was some Flipper shenanigans.

Dolphins can think abstractly. Source: (english.sina.com)

DOLPHINS ARE INTELLIGENT ANIMALS

Researchers and scientists who study dolphins have long noted the animals’ high intelligence and complex social structure. Dolphins are easily trained and great a copying behavior, but they also demonstrate that they can learn new information and then apply that knowledge to other situations. They can think abstractly, reason, and solve problems. They also display emotional traits such as empathy, happiness, self-awareness, sadness, frustration, and more.

Dolphins seem to appreciate that humans are almost as intelligent as they are. Source: (viralserv.com)

HELPFUL DOLPHINS ARE NOT JUST A LAGUNA THING

Laguna, Brazil is the best-known example of cooperative fishing between humans and dolphins, but it is not the only one. In Australia, there are legends about aboriginal people fishing with the assistance of dolphins. In Burma, dolphins signal fishermen where to cast their nets. In Mauritania, dolphins are known to direct schools of mullet fish to the shallows of the beaches, allowing humans to easily catch them. Dolphins appear to want to partner with humans, perhaps because they know we are almost, but not quite, as intelligent as they are.