 Patrols increasing after four beachgoers bitten by sharks on South Padre Island, Texas. Rescuers dragging Tabitha Sullivan out of the water. Sullivan's daughter says her mom is in stable condition. Her father was bitten, too, while fighting off the shark. A fourth person also grazed. It's just the latest in a string of shark encounters. Surfer Tomayo Perry killed by a shark in Hawaii. And another man bitten just yesterday in New Smyrna Beach, Florida. Experts say sometimes sharks are just chasing bait fish in shallow water. ABC's Morgan Norwood.