Just because you cant see them doesnt mean that theyre not there! They are there though. Just use common sense-dont go into the water if you see one, if youre bleeding, dont pee in the water (yes that attracts them too), dont spearfish (in case you were thinking about it), dont yell, thrash and splash around a lot, dont harass them, and personally I dont venture out beyond thigh deep water. Dusk and dawn are prime feeding times and the light isnt very good, so this is often when mistaken identity occurs. It happens in murky water too. Most sharks are afraid of humans and will leave you alone. When they do bite, its usually in error and its usually a test bite. More people die each year from snake bites, car accidents, and lightning strikes!