Why Do Deep-Diving Whale Sharks Hang Out Near the Surface?

Written by on October 19, 2012 in Marine Life
Whale shark. Photo credit: Quenton Dokken, NOAA.

Whale shark. Photo credit: Quenton Dokken, NOAA.

New research reveals why whale sharks and other large fish frequently return to the surface after deep dives.

Unlike whales, sharks, tuna, swordfish and many other large fish don’t need to return to the surface to breathe.  It was thought that their surface-time following a deep-sea dive was primarily for feeding purposes, but it turns out that’s only partly true.

The team of Australian researchers determined that these animals swim to the surface to warm up after spending time in the cold, deep sea.

Michele Thums at the University of Western Australia’s Ocean Institute, and colleagues attached tags to four whale sharks in an attempt to gather regular information about the shark’s depth, the level of light, and the water temperature.

The found that the whale sharks made three types of dives

  • Day and night ‘bounce dives’ which involve spending only 10-20 minutes at depth
  • Extra-long, extra-deep dives lasting over two hours, followed by a long period at the surface

The researchers found that if the water was warmer during a dive, the sharks spent less time at the surface.

Thums explains that this is important research because it helps us learn more about what drives their movement, and “it will assist in predicting their responses to environmental change and ultimately developing effective conservation and management strategies.”

Whale Shark.

Whale Shark. Photo credit: NOAA.

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Copyright © 2012 by Marine Science Today, a publication of Marine Science Today LLC.

About the Author

About the Author: Emily Tripp is the Publisher and Editor of MarineScienceToday.com. She holds marine science and biology degrees from the University of Miami's Rosenstiel School of Marine and Atmospheric Science and a Master of Advanced Studies degree in Marine Biodiversity and Conservation from Scripps Institution of Oceanography. When she's not writing about marine science, she's probably running around outside or playing with her dog. .

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