Southampton study finds stripes can divert fish from danger

Researchers at the University of Southampton have discovered that black and white stripes are effective at encouraging fish away from underwater dangers.

Rivers and lakes can be fraught with dangers for fish, ranging from hydropower turbines to habitat modification and instances of pollution. Being able to divert fish away from these dangers could save vast numbers.

The novel solution, proposed by School of Engineering postgraduate researcher James Miles, would protect freshwater fish in a manner that is harmless, simple and cheap.

James says: “My PhD involved looking at fish behaviour and how freshwater fish respond to visual cues, and working out whether they can be diverted down different routes simply by using these visual cues.”

He used experimental flumes, up to 16 metres long, and tested a technique to display vertical black and white stripes on the sides. Then, during several experiments, he acclimatised minnows and brown trout to the water and monitored their reactions and movements within the flumes.

“I found that the fish tend to stay on the side of the flume where the visual cues are,” he says. “Fish naturally try to keep their visual field stationary, so they tended to line up with the vertical stripes and swim next to them or use them to help hold their position in flowing water.”

Read the full article in the latest edition of Re:action, the University’s research and enterprise magazine.