6,000 Feet Under: Whale Sharks’ Deepest Dives Detected

Marine ecologist Mark Erdmann swims with a tagged whale shark in Raja Ampat, Indonesia. Credit: © Shawn Heinrichs

Known as the “gentle giants” of the shark family, whale sharks are the largest fish alive today. But there is much that scientists have yet to discover about their biology and habits.

And these massive fish recently revealed a big secret — they’re capable of far deeper dives than previously suspected.

By using highly sophisticated fin-mounted satellite tags on whale sharks for the first time, scientists observed the deepest recorded dives by a whale shark — nearly 6,000 feet (1,800 meters), approximately the length of 27 football fields. [Image Gallery: Mysterious Lives of Whale Sharks]

Whale sharks (Rhincodon typus) live in warm and temperate waters around the world, and can grow to about 50 feet (15 m) in length. They are filter feeders, hoovering up not only plankton and fish eggs, but also small fish and squid. Sometimes their diet gets them into trouble with fishermen; when whale sharks swim too close to boats that are trawling for baitfish, they can get caught in the nets.

However, their tendency to tangle themselves up turned out to be a lucky break for a team of researchers in Indonesia.

Whale sharks had previously been difficult to tag with fin-mounted satellite tags — trackers used on a number of shark species that can transmit position, water depth and temperature — because the sharks are too big for divers to manipulate alongside a research boat in order to attach the devices.

But a team of scientists recently took a different approach — tagging sharks that had gotten trapped in fishing nets before they were released.

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