Female whale shark sets the record for longest migration
While the blue whale is largest living species on Earth, the title of largest living fish goes to the filter feeding whale shark.
Whale sharks can measure up to 40 feet in length and have a distinctly large mouth that can expand and scoop up plankton, small fish and crab as it swims along.
Don’t let the shark in its name scare you off, because despite their large size they are considered gentle giants and many tour groups specialize in letting you swim with groups of whale sharks.
But sadly the species is endangered and it’s been reported that over the past 75 years, almost half of the world’s whale sharks have disappeared.
There is a surprisingly limited amount of research that has been done on whale sharks, but a new study reported the longest whale shark migration that’s ever been recorded, revealing new insight into their migration patterns and behaviors.
Researchers from the Smithsonian Tropical Research Institute tagged a female whale shark near the Coiba Island in Panama.
Whale sharks can be found in both the Atlantic and Indo-Pacific, and large groups of whale sharks have been reported near the Galapagos, Australia, southern China, and Seychelles.
For this study, the researchers tagged sharks near the Coiba Island in a World Heritage Site that is protected.
The female whale shark was named Anne and the tag attached to the shark signaled her position during migration using the Advanced Research and Global Observation Satellite (ARGOS).
At first, Anne stayed near Panama for 116 days before swimming toward Clipperton Island in France, next she moved on to the Cocos Island in Costa Rica as she made her way toward the Galapagos.
The signal was lost for 235 days during her migration which meant that Anne was swimming too deep for the satellite to pick up the signal from the shark’s tag. Anne was detected again near Hawaii and she eventually arrived at the Marianas Trench which houses the deepest spot in the Earth’s surface.
Overall, Anne traveled from the Eastern Pacific to the Western Indo-Pacific covering a distance of over 12,000 miles.
Whale sharks can dive to more than 6,000 feet, but researchers are not sure why the species dive down to these lower depths or migrate such large distances.
“We have very little information about why whale sharks migrate,” said Héctor M. Guzmán, lead author of the study. “Are they searching for food, seeking breeding opportunities or driven by some other impulse?”
Previous genetic research has revealed that whale sharks worldwide are closely related which means they must travel long distances to mate, but this latest tracked migration covers the longest distance ever recorded.
The whale sharks’ endangered status unfortunately is not doing enough to protect it from hunting or getting caught in fishing nets as regulations are often not enforced. Their pull as a tourist attraction can also be harmful to the sharks’ populations.
“Whale sharks in Coiba have already changed their behavior to avoid the surface and tourists,” said Guzman. “These studies are critical as we design international policy to protect transboundary species like the whale sharks and other highly migratory marine species.”
Image Credit: Kevan Mantell