Seasonal Change Brings White Sharks To Florida, Says UF Shark Expert

November 13, 1996

GAINESVILLE — Cooler temperatures that mark the terrestrial migration of human snowbirds to the Sunshine State also encourage the ocean’s most dangerous predator to make its voyage here, says a University of Florida researcher.

Great white sharks, the toothsome fish made famous by the “Jaws” movie, are rare on the east coast of Florida because they are cold water creatures, said George Burgess, a UF biologist and shark expert.

But they can be found in the cooler waters off the state’s shoreline between December and March, said Burgess, who is director of the International Shark Attack File, housed at the Florida Museum of Natural History on the UF campus.

“Occasionally a fisherman will pick one up,” he said. “Everybody who sees a white shark seems to have this inclination to put its jaws on their mantle.”

One of the threatened species of sharks, white sharks are almost certainly less plentiful than they once were along the East Coast and in the Caribbean because of loss of natural prey and over fishing, Burgess said.

“It says something that we have to worry about protecting the fiercest critter on earth,” he said. “White sharks are apex predators. They’re at the top of the food chain. They have no predators, other than us.”

Conserving the white shark is important because the species has survived so well from an evolutionary standpoint — the oldest sharks having lived 380 million years ago — that humans can learn from its success, Burgess said.

Scientists are beginning to develop a better understanding of the biological and behavioral aspects of white sharks, thanks to a recent research boom, he said.

New findings on these marine predators show their attacks on humans, which are extremely rare, in virtually all instances appear to be cases of chasing after what the sharks think is an appropriately sized food item, Burgess said.

In the coastal waters off California, which leads the nation in white shark attacks, white sharks normally prey on seals or sea lions that stray from their packs, Burgess said. Humans who are victims usually also are swimming alone, he said.

“That’s why fish swim in schools, birds fly in flocks and antelopes run in herds,” he said. “Staying in groups is a good strategy to avoid predation and it’s a good one for humans as well. Whether it’s white sharks or the sharks we more commonly have here in Florida, swimming with other people lessens your chances of being attacked.”

More than three quarters of white shark attacks occur at the surface in the top five feet of water, the area where they normally feed on prey, he said.

“In talking to victims, researchers have learned that the majority of white shark attacks are sudden and violent,” Burgess said. “Often the shark will literally push the person out of the water with its mouth and swim with the victim for a short distance. This contrasts with the kind of attacks we normally have here in Florida, involving blacktips and spinners, where a swimmer may feel the pressure of something grab a limb and then let go, not even realizing it was a shark attack.”

The number of white shark attacks have increased over the years, simply because more people are in the water where these creatures are found, thanks to human population growth, warmer wet suits allowing swimmers and surfers to brave cold temperatures for longer periods of time and an increase in use of nearshore waters for recreation, he said.

That three quarters of white shark attacks occur on humans wearing black is thought to be based on these people’s resemblance to the shark’s normal prey, such as seals and sea lions. The incidence of attacks increases to 89 percent when people wear blue or black, Burgess said.

White sharks that migrate to Florida have to satisfy themselves with swordfish and other big fish because the larger whales and some of the seals they are accustomed to eating are not found in local waters, he said.

Larger species of fish are found in deep water, making it favorable to white sharks in terms of both food and cool temperatures, Burgess said. Although white sharks have been spotted in the warmer Gulf of Mexico waters, they are rare, he said.