Shark gives researchers the slip

October 16, 2004

HYANNIS, Mass. --A great white shark has reclaimed its privacy after shrugging off a data-gathering device attached to it by researchers during its much-publicized stay in shallow waters off Cape Cod.

"It's a huge disappointment," said Gregory Skomal, Division of Marine Fisheries shark specialist. "It's really a kick in the stomach for a lot of people."

Shark experts had been excited about the data the device could yield, because very little is known about great whites' behavior in the Atlantic, the Cape Cod Times reported.

The device was programmed to transmit six months' worth of information on water temperature, depth and light levels and also help scientists reconstruct the fish's movements.

The 14-foot, 1,700-pound female shark became an international celebrity when it stayed in a lagoon off Naushon Island for a fortnight.

Skomal attached the device to the shark's dorsal fin while it was in the lagoon on Sept. 23 using a six-foot spear. But according to data received from the tag, Skomal said it appeared the device became detached shortly after the big fish was coaxed to open water Oct. 4.

Ironically, the shark's stay in the lagoon, which allowed attachment of the tag, may have caused the device to fall off, the Times reported.

An internal mechanism within the tag detects changes in depth and if those changes are not large or frequent, the tag "thinks" that the fish is dead and detaches.

"These devices have a high rate of failure, mainly because we're dealing with such vigorous animals," said Sean Van Sommeran, executive director of the Pelagic Shark Research Foundation, a California-based organization that has tagged nearly 100 great white sharks on the West Coast over the past decade.

"I saw the photos, and Greg (Skomal) placed the device perfectly," said Van Sommeran. "So there was no `pilot error.' But even well-placed devices do fail. It's no easy business."

Skomal said the tag was floating in the open ocean, approximately ten miles south of Martha's Vineyard and asked boaters to be on the lookout for a white object that looks like "a pingpong ball attached to a cigar" because the device still contains raw data that hasn't been transmitted.