If you are swimming and spot a shark too close to outrun, the worst thing you can do is turn your back on it. That's according to Gavin Naylor, Director of the Florida Program for Shark Research at the Florida Museum of Natural History and a featured expert on SHARKFEST, the annual programming event dedicated to shark science and conservation.
Below, Naylor lays out what swimmers should actually do in that, how sharks migrate, why public fear of them is often overblown, and the outsized role they play in keeping ocean ecosystems in balance.
Naylor says sharks, like other predators, go where the food is.
"They're going to move to wherever they can make a living most readily," Naylor said. "And that often means following the fishes that they feed on."
Some species make long, predictable migrations. Naylor pointed to blacktip sharks along Florida's east coast as an example.
"The blacktip sharks that we see off the northeastern coast of Florida, actually all the way along the eastern seaboard, routinely make migrations from the Carolinas down to South Florida, and from South Florida back up to the Carolinas when it warms up," he said.
Other species stay put. Naylor said the pattern comes down to what each species eats and where that food source is.
As for the public's fear of sharks matching the actual risk, Naylor said the numbers tell a clear story.
"If you look at those numbers, then we should be far more terrified of driving than we are of swimming in the sea," he said. "Quantitatively, it's an overblown risk."
But Naylor said people don't process risk that way.
"The imagined terror of being bitten by another organism sort of outweighs the quantitative risk," he said. "People almost seem to enjoy being terrified. That's the only explanation I can come up with, because quantitatively it makes no sense whatsoever."
Naylor offered direct advice for swimmers who spot a shark and can't make it back to shore right away. The most important step, he said, is to keep watching the animal.
"Always face it," Naylor said. "Many predators will, if they are targeting you, try to come from an angle where you don't anticipate them."
He recommended swimmers with a mask or goggles put their heads underwater to track the shark's position, then move steadily toward shore while keeping the animal in sight.
"If the animal comes up and it engages you or if it bumps you, I think the best thing to do is to whack it pretty hard on the front of the nose if it's within range," Naylor said. "It will be more surprised than you are. The nose is very sensitive, and it'll probably be spooked and swim away very quickly."
His summary: avoid contact when possible, and if a shark presses the issue, a firm strike to the nose is usually enough to send it away.
Naylor described ocean life as a pyramid, with plants and algae at the bottom and predators that feed on other predators near the top.
"Most sharks are sort of mesopredators — they're not right at the top, but there's a few that are apex predators right at the top," Naylor said. "If you remove those from the very top of the pyramid, they will have these reverberations throughout the entire structure."
Removing sharks, he said, can set off a chain reaction: prey species multiply, then deplete the species below them, triggering a cycle of "re-equilibration" that can include events like red tide blooms.
"Sharks occupy a fairly apical or mid-level influence in the ecology," Naylor said. "If you remove them, they're likely to have outsized influence than if you removed the same number of individuals lower down in the pyramid."