listen to this. scientists are studying whether sharks are able to avoid danger. here with that is cnn s john zarelia. a 6-foot sharp. we have a nice lemon, guys. reporter: the researchers work quickly, taking blood and tissue samples, measurements. university of miami researcher, neil hammershrag is studying the habits of sharks in florida waters. the oil spill has given his company a new more urgent dimension. there is the possibility the animals might be able to anticipate the oil or sense the oil and move away from it. it s really unknown right now. reporter: this lemon shark will provide valuable data. but when it comes to what hammerslag is looking for, it s, well, a lemon. he s after the great sharks, tigers, hammer heads, bulls. they travel greater distances. if his team lands one, it will be tagged with a satellite
mexico, because they don t want people to catch and eat that fish. but, you o, i don t know if the sharks got the memo. reporter: because it s a natural predator, a reduced shark population impacts the balance of nature. there will be enough work, scientists say, to keep researchers busy, studying the effects of oil on sharks for decades. john zarelia, cnn, in the gulf of mexico. and hello once again, i m brooke baldwin in for tony harris. and top of the hour here in the cnn newsroom, where anything can happen. here are today s top stories. the senate begins its confirmation hearing for supreme court nominee, there she is, elena kagan. cnn with the best political team on television coming your way. also, senators mourn robert byrd, the west virginia democrat, the dean of the senate, dies after serving more than half a century on capitol hill. and it looks like tropical