Shark expert Dean Fessler has advice for edgy swimmers not convinced the odds of an attack are unlikely.

Fessler emphasizes the importance of not swimming alone and not swimming at sunset or sunrise. Those are shark feeding times, and the animal targets weak prey. He confirms sharks' sense for blood and discourages swimming with open wounds.

At least one shark myth is not true, he says. According to Fessler, the old wives' tale that a punch in the nose will fend off a shark is not true. He recommends poking the eyes or grabbing the gills as better defense.