Discovering swimming secrets from watching water flow

To fully understand how and why aquatic animals are shaped certain ways and move the way they do, we need to be able to see the effects their movements have on the water surrounding them.  Visualizing water flow can be done in labs using laser light sheets to highlight tiny particles in the water and to track their movements through video analysis.  Our study took this method one step further to see if we could learn about how various animals swim in their ocean habitat under natural water flow (insead of steady flows created in lab flow tunnels).  With equipment developed at Caltech, we took the lab to the sea and I went diving with an underwater camera with a laser attached in just the right position to create a light sheet in front of the lens.  Then, all we needed were the animals!  We set out to test this set up with larger and faster animals than it had ever been used with before, we settled on a fish, the white seabass (shown below left), and two mammals, dolphins (below center) and humans (in fins, below right). 

Results

While we suffered from a few techincal difficulties, overall, we learned that this technology provides a promising new frontier to help us understand hydrodynamics, body design of aquatic animals, and swimming behavior. With more time, practice, and the right lasers the possibilities are exciting to imagine!

Collaborators

Prof. John Dabiri: California Institute of Technology

Prof. Malcolm Gordon: University of California, Los Angeles

Locations

Dolphin: Long Marine Lab, Santa Cruz, CA

White Seabass: San Diego Oceans Foundation & Hubbs Sea World net pens in San Diego Harbor, CA

Human: Matt Smith, near Jack Dunster Biological Reserve and Long Beach Rowing Association, Long Beach, CA

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