04 July 2005

Bull sharks are common in Florida waters, but not the deadliest

Great whites and tigers are bigger, but the scariest shark people are likely to encounter in Florida is the bull shark.

A bull was blamed in the fatal attack Saturday on a 14-year-old girl, bitten in the leg as she swam off the beach in Walton County in the Panhandle. Monday, a shark bit a teenager swimming in waist-deep water about 80 miles from the site of the other attack. Doctors amputated the boy's leg, and he is expected to recover.

Unlike their larger, more notorious cousins, bull sharks are common in Florida coastal waters. Divers see them among ships sunk as artificial reefs off Broward, Palm Beach and Miami-Dade counties, where the sharks feed on fish drawn to the wrecks. Unique among sharks for their ability to tolerate fresh water, bulls penetrate deep into the Florida peninsula through its rivers.

"They're a very large shark and they have a very large mouth," said John Carlson, a marine biologist with the National Marine Fisheries Service, who studies sharks in the Gulf of Mexico. "Unlike some other species, they're found fairly close to shore."

In southeast Florida, divers say nurse sharks are the most common sharks. But Caribbean reef sharks and bull sharks rank after that.

"Bull sharks have definitely charged at me," said Jim Mimms, owner of Ocean Diving in Pompano Beach. "I've had to push them off me, push them away. It's a very uncomfortable feeling when you're diving, being stalked by a shark."

Another diver, Jeff Torode, owner of South Florida Diving Headquarters, says he's found bull sharks to be reclusive. Once while filming an underwater tourism movie, Torode saw two bull sharks at the Rodeo 25, an old Dutch freighter sunk as an artificial reef.

"We tried to get in close," he said. "They spooked. They swam off into deeper water."

Torode estimates he sees bull sharks eight to 10 times a year.

"They're more afraid of us," he said.

While blacktip sharks are among the biggest culprits in Florida shark bites, those attacks are hit-and-run affairs, usually broken off as soon as the shark realizes its mistake. A bull shark, which can reach a length of 11 feet, can take off an arm or leg. They are among the few sharks that eat other sharks.

Bull sharks have killed at least 22 people worldwide since statistics began being kept, second only to tiger sharks and great whites, according to the International Shark Attack File in Gainesville.

The true number of fatal attacks is likely to be far larger, because bull sharks are harder to identify than tigers or great whites, which means they probably account for a significant number of attacks in which the species is unknown.

Experts disagree whether it was a bull shark or a great white that was responsible for the infamous series of attacks in New Jersey in 1916 that left four people dead and inspired the book Jaws. The attacks took place in Matawan Creek, several miles from the open ocean, the sort of waters that would draw a bull. A great white was caught near the scene, but a nine-foot bull was also caught 10 miles away.

In Florida in 2001, a bull shark bit the arm off an 8-year-old boy near Pensacola. The year before, a bull shark killed a man as he swam near a dock by his house in St. Pete Beach.

The shark's eerie habit of swimming up rivers accounts for its name in different parts of the world. In India, for example, it's the Ganges shark. In Australia it's the freshwater whaler or Swan's River whaler. Bulls have established a population in Lake Nicaragua, reaching the lake through rivers linking it to the ocean. They have penetrated more than 2,000 miles up the Amazon River and more than 1,800 miles up the Mississippi. In 1937 a fisherman fought a five-foot bull shark in a fish trap on the Mississippi in Alton, Il.

There have been reports of bull sharks in Lake Okeechobee.

Like most sharks, despite their fearsome reputation, bulls are generally on the losing end of the encounter between sharks and people. Large coastal sharks, which include bulls, are classified by the federal government as overfished. Bull sharks are not targeted for commercial fishing, unlike blacktips and hammerheads, which get caught in nets to feed East Asia's appetite for shark fin soup.

But like other large marine predators, they run a gantlet of nets and lines, where they risk being caught unintentionally as by-catch of other fisheries. The World Conservation Union classifies bull sharks as "near threatened."

Federal scientists in the Gulf of Mexico are tagging bulls and other sharks to learn where they go, so eventually habitat can be set aside for them and protected, said Carlson, the shark scientist with the National Marine Fisheries Service.

Protecting habitat for sharks can be a delicate business. But Carlson said top predators such as sharks play a role that we must respect because we don't know the environmental consequences of removing them.

By accounting for so many serious attacks on people, the bull shark makes it more difficult for conservationists to protect the 400 species of sharks, the vast majority of which never attack people.

"In general, shark conservation is an uphill battle," said Sonja Fordham, international conservation manager for the Ocean Conservancy, "because they're not as loveable as other species."

Source: www.dailypress.com


At 5:29 PM, Blogger Gail said...

We saw two bull shark pups feeding in two feet of water! My 12 year old daughter and I were just about to run into the water...we made a splash in ankle deep water when what to our surprise...two bull sharks surfased three feet away from us in knee deep water at Fort Fisher State Park on the ocean side in North Carolina!!! Too close!!!


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