A fish swimming in a school consumes less energy, the researchers found out

Fish it is difficult to swim in coastal waters and rivers, where the bottom shapes cause the currents to swirl.

For example, salmon have been measured to consume up to one and a half times as much energy in a swirling flow as in an equally fast steady flow. It’s easier to get there when you stick together, it’s now been discovered.

US researchers tested the matter in the laboratory with turquoise zebrafish. They swam the fish alone and in a school of eight individuals in a flow tunnel where they adjusted steady and swirling water flows.

The researchers evaluated the fish’s performance by videotaping their movements and measuring their energy consumption.

When swimming in a school, the fish consumed up to 80 percent less energy in the strong swirling than when they exerted themselves in the same conditions alone. A solitary fish had to whip its tail much more vigorously in order to swim as fast in a swirling current as in a steady current. There was no need for it in Parve.

During the eddying, the fish drew closer to each other, which smoothed out the movement of the water between them and made swimming easier, the researchers explain In Plos Biology.

Published in Science in Nature 6/2024