In the name of science, Bob can swim wherever he wants. However, he usually refrains from entering the protected zones unless a law enforcement boat is by his side, its dive flag up and a uniformed officer at the ready to explain who he is and what he's doing. Despite the fact that Bob's out here regularly in the winter conducting field research, he maintains a low profile. The last thing he wants to do is set a bad example and encourage others to trespass. Manatees come here for the warm natural springs that feed the river.
People come here for the manatees.
Some, overzealous in their excitement to interact with this mellow marine mammal, disturb the animals when they're resting on the bottom or nursing their calves. They grab flippers and tails. The largest mammal database Bob appreciates it, even when it's at his expense, that people are rabidly protective of the species he's been studying for 22 years. Of the animals that come here, Bob knows many at a glance. Even to my untrained eye, certain scars are easy to distinguish.