Shark Rx

For biologist Jim Gelsleichter, a good day at work is one when he hooks enough bull sharks that his arms are covered in "shark burns" - rashes caused by rubbing elbows, so to speak, with the feisty rough-skinned fish. Fortunately, he and his team are catching juveniles, typically just a few weeks old, and around two feet in length. While one researcher holds down the squirming baby, another can safely collect 5mL of blood and insert a small nylon dart tag in the base of the dorsal fin. To each tag Gelsleichter affixes a pair of dime-sized silicone-rubber discs that absorb the chemicals in the coastal waterways of southwest Florida, where the sharks are swimming.