Shark sense

Tiger sharks memorize where they’ve scored consistently good meals and find their way back there across vast expanses of ocean, Hawaii researchers have found.

Unlike bears, which can teach each other where to find food, sharks apparently don’t share that information, the scientists said. Instead, each shark learns on its own where to find food and incorporates that information into a “cognitive map,” a kind of personal GPS navigator.

Beginning in May 2006, University of Hawaii marine biologists Carl Meyer, Kim Holland and Yannis Papastamatiou tracked five tiger sharks and three Galapagos sharks around in the Northwestern Hawaiian Islands using acoustic and satellite transmitters.

The results, published online May 5 by the journal Marine Biology, showed that one popular dining site is tiny islands at French Frigate Shoals where albatross eggs hatch in late spring and early summer.

“The precise, seasonal arrival of certain tiger sharks at (French Frigate) in time for albatross fledgling indicates these sharks may also use internal clocks to guide their movements,” the research paper says.

On voyages aboard the Hi’ialakai, a ship operated by the National Oceanic and Atmospheric Administration, the scientists caught sharks using hooks baited with tuna heads. From a 20-foot skiff, they roped each shark’s tail and flipped it belly up, which places the predator into a docile mode known as “tonic immobility.”

They then installed three types of trackers: