One of the most ambitious expeditions ever to tag great white sharks
set sail July 30 off Cape Cod, Mass. The researchers
hope to tag as many as 20 of the enormous sharks, about which very
little is known.
The project is expected to be the largest
shark-tagging mission in U.S. history, according to the nonprofit shark
research group OCEARCH, which is leading the mission along with the
Woods Hole Oceanographic Institution (WHOI). The effort is part of an
initiative to better understand the animals and to inform the public
about the importance of sharks, which serve as top predators and are
vital for the proper function of ocean food webs, said WHOI researcher
Simon Thorrold. As many as 100 million sharks are killed per year due to
both legal and illegal fishing, a recent study found.
much interest there is in great white sharks, we are still
scientifically trying to find out the very basics," Thorrold said.
Tagging great whites
a vessel known as the M/V OCEARCH, researchers will cast lines for
great white sharks, using barbless hooks designed to minimize harm to
the animals, Thorrold said. After the shark is reeled in, a special
platform powered by a hydraulic lift is then raised up underneath the
shark, allowing scientists to attach a GPS tag to the animal's dorsal
fin and perform a variety of tests on the animal, Thorrold told
LiveScience's OurAmazingPlanet. [ Video of Great White Shark Tagging ]
have to work quickly to minimize the stress they cause the sharks,
Thorrold said. During the 15 minutes the researchers spend with each
shark, the animal's gills are bathed in saltwater to prevent the shark
"It's like a NASCAR pit crew," Thorrold said.
Perhaps surprisingly, the sharks don't seem to put up much of a fight,
and "really chill out on the platform," he added.
expedition, which runs from July 30 to Aug. 29, the scientists will take
blood and tissue samples from each of the sharks they catch to learn
more about the animals' health and diet. The GPS tags will allow
scientists to see where the sharks are going, as well as the temperature
of the water and the depths of their dives, Thorrold said.
data derived from the tagging of great white sharks has shown that the
animals follow two basic routes. Some of the sharks tend to stay along
the East Coast and linger not far from the shore, Thorrold said. But
others set out into the Atlantic Ocean, before making a wide circle and
heading toward Bermuda. Previously, it wasn't known that sharks wandered
far from shore, Thorrold said, adding, "That really blew our minds."
data will be used in as many as a dozen studies and will help
scientists understand the sharks' behaviors. More and more great white
sharks have been spotted off Cape Cod in recent years - a development
that has coincided with the rebound of populations of gray seals, upon
which the sharks feed, Thorrold said.
Earlier this year, OCEARCH
scientists tagged a shark named Lydia off the coast of Florida. Lydia
and other sharks can be tracked at the Global Shark Tracker.