Experiments show that wild fish can recognize individual divers

For years, there have been issues with the scientific diversity of Mediterranean research sites. At some point in the seasons of all fields, local fish followed them and stole food intended as experimental rewards. Interestingly, these wild fish appeared to recognize certain divers who had previously carried food, and chose to follow them while ignoring other divers.

To find out if that was true, a team from the Max Planck Institute for Animal Behavior (MPI-AB) in Germany conducted a series of experiments while wearing a series of diving gear. External visual cues.

The experiment was designed to answer questions that we had never asked before about wild fish. Can they pull people apart? Overall, there is little scientific evidence that fish can recognize humans at all. One breeding species, the shooter, was able to recognize computer-generated images of human faces in laboratory experiments.

“But no one ever asked if wild fish have the ability to recognize us when they enter the underwater world, or if they actually have a motive,” MPI-AB said. says Maëlan Tomasek, a doctoral student and a student at the University of Clermont in France.

Now the MPI-AB team was asking, and the fish responded. Wild fish can recognize individual humans. And more than that, they follow certain divers who know they will reward them. The find published in Biology Letters credits the possibility that fish can distinguish relationships with specific humans.

Volunteered fish

The researchers conducted the study in the Mediterranean study site where wild fish populations are used to the presence of scientists, 8 metres underwater.

Their experiment was conducted in open water, and the fish took part in the exam as “an aspiring volunteer that they could be willing to go.”

If a fish can learn to follow an individual diver, the first experimental stage – training – has been tested. Training diver Solar started off by trying to attract the attention of local fish. She wore a bright red vest and ate fish while swimming 50 metres long.

Over time, Soller removed any noticeable clues until she wore plain diving gear, kept food hidden, and fed fish only after chasing 50 meters in full.

Of the dozens of fish species that live in the Marine Service, two species of Seabream, in particular, are particularly happy to engage in training sessions. Sea Bream is best known to us as the fish we buy to eat, but they surprised scientists with their curiosity and willingness to learn.

“Once I got into the water, it was only a few seconds to see them swimming towards me. Not only did Bream learn to follow her, but the same individual appeared every day to take part in lessons. I did.

Soller even tried to name them: “There was Bernie with two shiny silver scales on the back, and Alfie, who had a nip from the tail fins,” she says.

After 12 days of training, about 20 fish were sure to follow Soller in the training swim, and she was able to recognize some of them from their physical properties. The stage was set for the next experimental stage by identifying individual fish participating in the experiment. Test whether these same fish can communicate Solar separately from another diver.

2 Diver Test

This time, Sora dived at Tomasek. Tomasek’s dive gear was slightly different from her, especially in some colorful parts of the wetsuit and fin. Both divers started at the same point and then swam in different directions. On the first day, the fish chased both divers equally.

“We could see them having a hard time deciding who they’re going to chase,” Solar says.

However, since the second day, the number of fish following Soller increased significantly, as Tomasek never fed the fish that followed him. To ensure that fish are learning to recognize the correct divers, researchers focused on six fish from large groups to study individually, four of which are powerful in the experiment It was found that the positive learning curve was shown.

“This is a cool outcome, because it shows that the fish aren’t just chasing Katinka out of habit, but that it’s not because the other fish were there,” Tomasek says. “They were aware of both divers, tested each one and learned that Katinka produced rewards at the end of the swimming.”

However, when Soller and Tomasek repeated the test, this time wearing the same diving gear, the fish were unable to distinguish between them. For scientists, this was strong evidence that the fish were associated with diving gear, perhaps different colours, and differences in each diver.

“Nearly every fish has chromatic vision, so it’s no surprise that Sea Bream has learned to associate the correct divers based on body color patches,” says Tomasek.

Fish knows what we look like

Underwater, we do the same thing. “The faces are distorted by diving masks, so we usually rely on differences in the wetsuit, fins, or other parts of the gear to recognize each other,” says Soller. As more time went by, the author says, the fish may have learned to pay attention to subtle human traits such as hair and hands to distinguish divers.

“We’ve already seen them approaching our faces and scrutinizing our bodies,” adds Solar. “It seemed like they were studying us, not the other way around.”

This study supports many anecdotal reports of animals, including human-recognized fish. But we go further by running a dedicated experiment in a completely natural context.

We discovered that wild fish can quickly learn to recognize individual human divers using specific cues. That’s because many other fish species, including our pets, can recognize certain patterns and identify us, scientists say. This mechanism is the basis of special interactions between individuals, even across species.

“These animals sailing through complex worlds and interacting with countless different species every minute are not shocking to me,” said Alex Jordan, a senior author who leads the MPI-AB group. A cue.

Tomasek said, “It may be strange to think of sharing bonds with animals like fish that are far from us in evolutionary trees. If we care about paying attention, Evolution distance.