Fish recognize divers

He saw it several times for almost 20 years of research with fish at freedom. Alex Jordan directs the animal behavior evolution laboratory (Germany). He had the feeling that the fish he studied learned to recognize him and to follow his colleagues. Do the fish really recognize the divers?

"There were many occasions in which we seemed clear that the fish recognized us," he recalls. They decided to do a study. They designed experiments with two different species of fish: the golden sorry and the black gold. For a month, the team made more than 30 dives between four and eight meters deep.

Experimenting

The results of his study suggest that the fish could recognize the divers for the color of their team. A diver put on a colored vest and floated for five minutes while fed the fish with prawns. Then he swam 50 meters in a straight line and rewarded the fish that followed it with more food. After the tenth immersion, he gradually stopped feeding the fish and carrying the colored vest. An average of 13 fish learned to follow.

Then two researchers with different color diving equipment entered the waters. They floated at the same point for three minutes before swimming in opposite directions. At the end of the swim of 50 meters, the first diver rewarded the fish with food. The other did not. This part of the experiment lasted 10 days, with a total of 5 dives.

The first day of this experiment, the fish followed both divers. Then they followed the researcher who rewarded them with food. In the final experiment, the divers repeated the routine with identical costumes.

Following the suit

This time, the fish could not recognize the diver who had feed them and followed both. They used the different colors of the diving team to distinguish the two divers and follow the one who feed them.

The fish recognize the divers. Now they want to check if fish can learn to recognize human attributes. Like hair, eyes and face. The study could have implications for researchers studying fish in freedom. If animals can recognize and follow concrete scientists, they could accidentally skew the results of the experiments.