Biggest Fish in the Ocean Continues to Confound Us

Scientists tried new research techniques on the whale shark, but they haven't learned much yet
By Newser Editors and Wire Services
Posted Feb 28, 2018 9:25 AM CST
Biggest Fish in the Ocean Continues to Confound Us
In this 2017 photo provided by Simon Pierce, a whale shark swims past Alexandra Watts in the Galapagos Islands area of Ecuador.   ( via AP)

It's the biggest shark—and the biggest fish—in the sea. Yet despite its hulking appearance, the whale shark has only tiny, almost useless teeth and is sometimes so docile that entire boatloads of people can swim alongside the enigmatic, spotted beast. It's also one of the least understood animals in the oceans. In an attempt to solve some of the most enduring mysteries, a group of scientists spent several weeks diving with whale sharks in the Galapagos Islands last summer and fall. They tried some never-before-used techniques on the species in the wild: taking blood samples and doing ultrasound exams. But researchers managed to obtain only two blood samples, which haven't yet been tested, and the ultrasound exams were inconclusive, due in part to the thickness of a whale shark's abdominal wall: about 8 inches.

Besides blood and ultrasound tests, scientists successfully tagged seven sharks. While not a large number, it's important since so few whale sharks are tracked. The pressure of deep water can cause tags to drop off if the sharks dive below 6,561 feet, which the animals often do if they're traveling long distances or possibly giving birth. But any migratory data the scientists collect when sharks stay at shallower depths can help build a picture of the sharks' life cycle, reports the AP. "The million-dollar questions are where are they mating, hunting, and where do their young live?" said Jonathan Green, director of the Galapagos Whale Shark Project. Only one pregnant whale shark has ever been found: In 1995, a dead whale shark was found off the coast of Taiwan with 300 embryos inside, all at different stages of development. (The slaughter of a whale shark drew outrage in 2016.)

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