Florida shark attack a great white? Probably not, says researcher

Stephen Schafer, a Florida kite-surfer was killed by what some news outlets are claiming was a “swarm” of great white sharks about a quarter mile off Stuart Beach in Martin County Florida.

Bitten multiple times and having tried to fend off his attacker or attackers, he still had the strength to try to make it to shore. Daniel Lund, the life-guard who noticed a kite-surfer apparently in distress about 500 yards offshore and launched himself into the water with his rescue board, said he noticed a number of sharks in the vicinity when he reached Mr. Schafer.

The rare fatal attack has prompted a flurry of speculation in the media on the culprit, with much of the early analysis pointing towards the great white, the cold-water favoring species that can reach lengths of more than 15 feet.

But George Burgess, who runs the Florida Program for Shark Research and helps run the International Shark Attack File, an online database of shark attacks, disagrees.

Speaking by cell phone while driving down to examine Schafer's wounds to determine what species was responsible for the attack, he cautioned against jumping to early conclusions as to species or whether one or more sharks were involved.

Tiger and Bull Sharks more opportunistic feeders

But he said that the waters Schafer was surfing in are among the warmest in Florida at this time of year and that both tiger and bull sharks are more opportunistic feeders than great whites.

“The tiger and the bull shark are certainly found in the areas where the attacks occurred all year round, and they’re the most likely ones based on the their large size, [and that they] like to go after large prey, and are evolutionarily more curious,” says Dr. Burgess. “The tiger shark has a very wide taste, and will try to eat almost anything and from them comes sharks’ overall reputation that they’re not very selective, though the fact is that most species are specialized feeders.”

“I would disagree that a great white is likely,” he says. “They are the ones that are least likely to be found there right now. The white shark is a blue-water shark that might be in Florida in the winter time and in very limited numbers – juveniles, mostly – but it’s less likely.”

Adult great whites tend to specialize in feeding on cold water ocean mammals like seals, whose rich blubber stokes their bulk, which often tops 3,000 pounds. Juveniles typically feed on fish.

A number of researchers have theorized that adult great white attacks are almost always a case of mistaken identity, keying off the fact that they typically take one bite of a human and then release them. The theory is that the sharks don’t want to fill their stomach with less nutrient rich prey.

Tigers, on the other hand, will eat just about anything. Bull sharks, which favor murky waters close to shore, are happy to feed on cows or other dead creatures that flow into the ocean.

Attacker not necessarily a great white shark

To be sure, it could be another shark entirely. Dr. Burgess says that there are 12-15 species in those waters at this time of year that might have bitten Schafer. That said, he’s still leaning towards expecting it was a tiger or a bull.

“Both tigers and bulls tend to go after sea turtles which are large animals that have heavy shells and present as a larger prey item,’’ he says.

The problem for humans in the water is that sharks are adapted to focusing on prey that demonstrates “erratic” movement, usually the sign of a sick or injured animal that’s easier to catch. “Any sort of irregular activity is something that a shark picks up on pretty well, a human doing almost anything in the water seems erratic, certainly something like the large splash of falling off a surfboard.”

While more and more humans venture into the ocean for recreation every year, shark attacks are exceedingly rare. The International Shark Attack File has confirmed 137 unprovoked fatal shark attacks since 1580. Of these, great whites have been responsible for 65, tiger sharks for 27, and bull sharks for 25. In Florida, there have been 610 shark attacks since 1882, 13 of them fatal. Today’s attack was the first fatality since 2005.

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