In shoals, fishes like school kids follow rules
London: At school it is all about watching the kid nearest to you and making sure you do what they do. Fish apply the same rules when travelling in small shoals, say researchers.
Researchers from Uppsala University, Sweden, working with Sydney University biologists came upon this comparison when studying groups of a small lake-dwelling fish, known as the mosquito fish.
Some of the most mesmerizing sights are seen in the collective motion of fish schools and shoals. In the ocean, vast schools of hundreds of thousands of fish can form which then move together in perfect unison, the journal Proceedings of the National Academy of Sciences reports.
By tracking the fish using computer imaging and fitting mathematical models to how the fish interact with each other, the researchers were able to decode the rules by which these fish interact with one another. The rules turned out to be strikingly simple but effective, according to an Uppsala statement.
Fish try to catch up with other fish in front of them, but they slow down when they get too close.
Much in the same way as car drivers on an open highway try to keep a fixed distance from each other.
Fish also turn their bodies to move towards their neighbours and appear to react primarily to only their nearest neighbour. Through these simple rules, shoals of mosquito fish move in a co-ordinated fashion.
These studies of small groups of fish set the scene for understanding how larger schools form and move.