The great white shark, Carcharodon carcharias, is the largest predatory fish on Earth. Depicted in popular culture as a cold-blooded killer, it is also one of several apex predators increasingly vulnerable to overexploitation and climate variability, and relatively little is known about their behavior.

A 10-year study led by Stanford University Marine Biologist Dr. Barbara Block attached 4,306 tags to 23 species, including some 200 great white sharks, to understand migration pathways and link ocean features to multispecies hotspots in the North Pacific Ocean. The study revealed that every winter, white sharks congregate in an area of the in the North Pacific Subtropical Gyre (NPSG), halfway between California and Hawaii, which was long assumed to be an ocean desert devoid of oxygen and nutrients. Scientists were puzzled as to why the white sharks routinely traveled some 1,300 miles to reach this desolate area of ocean. They dubbed the area the “White Shark Café.”

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A map showing the saildrones’ tracks from San Francisco to the White Shark Café.

In 2018, two Saildrone unmanned surface vehicles (USVs) participated in a month-long multidisciplinary mission that included researchers representing five institutions and a combination of traditional and cutting-edge technology to track tagged white sharks to the White Shark Café. The mission was led by scientists aboard the Schmidt Ocean Institute’s research vessel Falkor.

“We now have a gold mine of data. We have doubled the current 20-year data set on white shark diving behaviors and environmental preferences in just three weeks, we have used shipboard tools that provided a rapid census of the predators and prey of a remote ocean region. This helps to establish a baseline of observations that will help us better understand the persistence of this unique environment and why it attracts such large predators,” said Block.

In the video below, watch the saildrones in action and hear from scientists participating in the mission discuss how they used the saildrones to investigate the White Shark Café.

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Go to data.saildrone.com to access the data from this mission.





Main photo: Elias Levy/Flickr





Resources:

Schmidt Ocean Institute, “Scientists Voyage to the White Shark Café,” June 4, 2018

B. A. Block, I.D. Jonsen, et al., “Tracking apex marine predator movements in a dynamic ocean,” Nature 475, July 7, 2011