Skip to content. | Skip to navigation

Personal tools
Log in
You are here: Home Blog Research finds that random water movement cost fish a lot of energy

Research finds that random water movement cost fish a lot of energy

By Leonard Ho - Posted Feb 04, 2014 10:00 AM
A new study has found that reef fish expend a lot of energy navigating through big waves especially when the water movement is chaotic. Constantly changing speeds is a huge energy burn, at least for fish that propel themselves with their pectoral fins (and that is most of the reef fish we keep). Does this finding change our approach to water circulation within aquariums? Are we tiring out our fish?

From Australian National University

Waves costly for fish

Big waves are energetically costly for fish, and there are more big waves than ever. The good news is that fish might be able to adapt.

“There has been a lot of recent work in oceanography documenting the fact that waves are becoming more frequent and more intense due to climate change,” says Mr Dominique Roche, PhD candidate from the Research School of Biology. “The habitats that fish live in are changing.”

“This is not a localised problem, but something that is documented globally,” adds Ms Sandra Binning, also a PhD candidate in the Research School of Biology.

Mr Roche and Ms Binning are co-authors on a study documenting the energy it takes for fish to swim through large, intense waves. Specifically, they focused on fish that swim with their arm, or pectoral fins, which are very common on both rocky and coral reefs.

“By controlling water flow in an experimental chamber with the help of a computer, we were able to replicate oscillations in the water flow like in a wave pool,” explains Mr Roche.

“We looked at how much energy the fish consumed while swimming without waves, in conditions with small waves, and in conditions with large waves. The idea was to compare the amount of energy that fish consume while swimming in these three conditions when their average swimming speed was exactly the same.”

Mr Roche and Ms Binning found that it’s a lot more energetically demanding for fish to deal with large fluctuations in water speed and wave height.

“It’s harder to constantly switch speeds than it is to remain at a constant speed, like a runner changing between running and a walking during interval training versus a steady jog. Well, it’s the same for swimming fish,” says Mr Roche.

“Things could get tough for fish in windy, exposed habitats if waves get stronger with changing climate. But there may be a silver lining,” says Ms Binning.

“In the swim chamber, when the water flow increased, fish had to beat their fins faster to keep up. But when the water flow slowed down, some fish took advantage and rode the wave. Essentially, rather than beating their fins frantically, these fish used the momentum that they had gained while speeding up to glide and save energy.

“This means that some individuals are better at dealing with waves than others, and that there is hope for populations to adapt their swimming behavior to potentially changing conditions in the future,” concludes Mr Roche.

Their research was recently published in the Journal of Experimental Biology.

Author: Leonard Ho
Location: Southern California

I'm a passionate aquarist of over 30 years, a coral reef lover, and the blog editor for Advanced Aquarist. While aquarium gadgets interest me, it's really livestock (especially fish), artistry of aquariums, and "method behind the madness" processes that captivate my attention.


Document Actions
Filed under: , ,
blog comments powered by Disqus


Contribute to our blogs!

Do you have news or discussion topics you want to see blogged?  Let us know!