How Swim Flumes Work

Volume 28, Number 3, February 2016

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How swim flumes work

Max Drakeley

Ever wondered if fish work out in the gym? No, me neither, but in aquatic research laboratories around the world you’ll find them stretching their fins, as referred to in Holly Shiels’ article on pages 2–6 of the magazine.

Swim flumes in research and beyond

Swim tunnels, also called ‘swim flumes’, are the equivalent of underwater treadmills, where animals are contained in submerged tanks/tunnels with carefully controlled water flowing through them in one direction. The speed at which the water flows through the tunnel can be changed, and the fish inside keep up the pace. While this all may sound like fun, there is a good reason behind it — it allows researchers to estimate some of the energy costs of behaviours in fish, and to decide which factors might influence these costs, such as temperature or diet.

The behaviours studied aren’t limited to endurance swimming. Aspects such as maximum speeds or the type of swimming can be measured, such as the fast-burst swimming that fish use to escape a trawling net. This is particularly important research in light of the dangers arising from overfishing with advanced trawling methods. Laboratory studies using swim flumes have shown that fish with higher anaerobic capacity are more likely to escape being caught in trawling fishing nets — check out this article: This research was undertaken by Dr Shaun Killen (from the University of Glasgow) and he has some captivating videos of flumes in action on his website: Make sure you check out his other videos on social (and antisocial) behaviour too.

If swimming in a flume sounds like a cool idea, don’t worry — they are available for humans too. Swim flumes are increasing in popularity with swimmers who are keen to own a pool that doesn’t take up too much space. Swimming in a flume is ideal for rehabilitation from injuries or improving technique for athletes.Some specialist flumes even have the ability to adjust to altitude. Follow this link to the New York Times for more information on their use:

In addition, swim flumes are being used to help improve safety in endurance swimming events. After the death of professional swimmer Fran Crippenduring a salt water race in the UAE (see scientists and sportsmen have become increasingly concerned about regulation of body temperature during these events — see this article from the Otago Daily Times:

So swim flumes allow measurements of metabolic rate, aerobic and anaerobic performance in humans, just as they do for fish. Since the temperature of the water can be controlled, studies assessing the performance of swimmers (or fish) can be used to identify high-risk situations when undergoing demanding physical exercise. Here is a short manual on a human swim flume at the University of Otago: