The World's Largest Whale Sharks Are Disappearing

Scientists are spotting fewer of the biggest whale sharks in global oceans, but no one is sure why.

You’d think finding something as big as a school bus would be a cinch. 

But large whale sharks—the biggest fish in the sea—seem to have vanished from the world’s oceans, scientists say. 

Until a decade ago, adult whale sharks measuring an awesome 43 to 49 feet (13 to 15 meters) plied warm waters from India to Belize. 

Today these biggest of the big are seen only in the eastern Pacific, a new study says. Animals elsewhere average a mere 23 feet (7 meters) and under, which are small fry too young to breed. (Read more about the incredible lives of whale sharks.) 

"Where are they?” marine ecologist Ana Sequeira of the University of Western Australia says of the big guys.

“We urgently need to know. ... We need to have the big mums and big dads to keep the species going," says Sequiera, who led a new study about the phenomenon. 

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