VOYAGE TO THE WHITE SHARK CAFE
The white shark is among the most iconic predators in the ocean. But for all their public exposure, the lives of white sharks remain shrouded in mystery. Their remarkable migrations and behaviors have come to light in the past decade, through the use of biologging tags. The tags allow researchers to follow the sharks as they journey, traveling thousands of miles into the open ocean, then returning each year to their coastal feeding grounds.
Principal Investigator Dr. Barbara Block and her team at Stanford University’s Hopkins Marine Station have been using electronic tags to track shark migrations for years. She and her colleagues from the Monterey Bay Aquarium have found that a large number of white sharks that forage each fall in the waters off California migrate annually to an open ocean region halfway between Hawaii and Baja. Fattened on a rich diet of seals and sea lions in the National Marine Sanctuaries along the central California coast, adult white sharks in winter and spring congregate in a patch of open ocean roughly the size of Colorado, known as the White Shark Café. Little is known about this remote sub-tropical environment and the behavior of sharks that convene there.
In April, a multidisciplinary team of oceanographers, marine ecologists, and molecular biologists will sail to the Café aboard the R/V Falkor with the objective of locating satellite and acoustic tagged white sharks and studying their surrounding oceanographic environment. The expedition will bring a broad range of tools to the task. Two types of tags were put on the white sharks: satellite and acoustic tags. The scientific team will also be using some advanced research tools testing the concepts of how to conduct ocean observing in open ocean ecosystems. Two Saildrones, unmanned surface vehicles that “sail” on a fixed wing, are equipped with sophisticated acoustic instruments designed to locate plankton and midwater fish. The team will also use an autonomous underwater vehicle called a Slocum Glider, which will be equipped with listening devices for the acoustic tags. The drones will signal to the team where the sharks are gathering and will help direct the deployments of the Falkor’s ROV and other ‘listening buoys’ equipped with camera systems.