Carrier and Pratt now use the new Pet Identification Tags (PIT tags, left) for shark tagging. These tags are "inserted under the skin without hurting the shark at all," said Carrier and Pratt. "It's like scanning groceries at the supermarket with the PIT tag reader," said Carrier.
"Rototags" (right) are also used to tag nurse sharks, and provide the scientists with a visual element that can be seen from above the water's surface. These tags are also used on farms for cattle and sheep.
Photograph by Mark R. Holmes