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.
Gelsleichter, based at the Mote Marine Laboratory in Sarasota, isn't testing the sharks for chemicals typically associated with aquatic pollution, such as mercury and PCBs. He's looking for traces of common pharmaceuticals that millions of ...
