Guy Harvey Magazine

SUM 2018

Guy Harvey Magazine is focused on fishing, boating, scuba diving, and marine conservation. Portfolios from the world's best fishing photographers, articles on gear, travel, tournaments, apparel, lifestyle, seafood recipes, sustainable fisheries.

Issue link:

Contents of this Issue


Page 39 of 83

40 | The desire to unravel nature's mysteries is part of the human DNA. And that passion for discovering the unknown often fuels innovation. From the compass, invented two centuries before Christ, to Galileo's telescope in 1609, to new, autonomous sailing drones, technology is often the key to unlocking secrets. This was evident on a recent month-long expedition that set out to decipher some peculiar behaviors of white sharks. Each spring, hundreds of the stealthy beasts leave California, swim for a month to the middle of the Pacific Ocean and hang out in a Colorado-sized area scientists have dubbed the White Shark Café. In late summer, they return to California and repeat the cycle each year. For two decades, scientists have been baffled by the shark's annual pilgrimage. The recent expedition aboard Schmidt Ocean Institute's research vessel Falkor included an interdisciplinary research team from five institutions led by Stanford University Marine Biologist Dr. Barbara Block. The science team employed some of the most advanced technology and successfully made a number of new discoveries, some of which completely reversed popular theories. "We now have a gold mine of data," said Dr. Block. "We have doubled the current 20-year data set on white shark diving behaviors and environmental preferences in just three weeks." In addition to the mystery of why white sharks visit the Café, there's also the curious behavior of the male sharks while they are there. The males repeatedly dive deeper than 500 ft. and back up again as often as every 10 minutes and more than 100 times per day. This was assumed to be some sort of mating ritual. "The male white shark and the female white shark are doing completely different things, and that's not something we've seen so much before," Block said. "We have to spend some time studying these behaviors to try to understand if this is courtship behavior or is this really a feeding or foraging behavior." The scientists had also previously believed that the area was virtually void of life. This was based on satellite scans showing low levels of chlorophyll. Without adequate chlorophyll, ocean productivity cannot occur. But, using deep-water sampling and a torpedo-shaped robot called the Slocum Glider that dove through the center of the Café area, the scientists discovered high levels of chlorophyll in deep water. "Because the chlorophyll concentration peaks deep in the water column,"

Articles in this issue

Links on this page

Archives of this issue

view archives of Guy Harvey Magazine - SUM 2018