24 February 2006

Shark attacks down in 2005 but up over long term

Worldwide shark-attack numbers fell in 2005 for the fifth year in a row.

Last year 58 confirmed "unprovoked" shark attacks occurred in natural ocean habitat, according to a report from the International Shark Attack File (ISAF), an organization based at the University of Florida in Gainesville.

That's down from 78 in 2000 and 65 in 2004.

Incidents in which the animals are provoked—such as during shark-feeding operations, in aquariums, or when fishers try to remove sharks from a net—aren't counted in ISAF's annual survey.

Four people were killed in unprovoked attacks last year, down from seven in 2004 and a bit below the 2001-to-2005 five-year average of 4.4 per year.

Last year's deaths included two in Australian waters, one in Florida, and one from the South Pacific island of Vanuatu.

Shark-attack fatality rates continue to drop decade by decade as improving medical treatments help boost the odds of survival in the rare event of an attack.

Long-Term Trend: More Attacks
Despite the media frenzy they spawn, unprovoked shark attacks are so rare that annual trends must be viewed with a grain of salt. The ISAF believes that decade-by-decade comparisons give a more accurate picture of trends.

Unprovoked attacks became more frequent with each decade of the 20th century. The first decade of the 21st century will likely continue that trend.

Yet those rising numbers don't likely represent any change in shark behavior.

Most shark specialists agree that the big-picture rise in attack numbers has more to do with humans than with sharks—namely the steadily increasing numbers of people living near and frolicking in the world's coastal waters.

In fact, fisheries data reveal that many shark populations are declining at serious rates or holding at lower than historic levels. The sharks' decline could be one of several factors in the recent dip in attacks.

"The decline in shark populations has occurred for a decade or two, but it may be that it has reached a critical level in [terms of] influencing the number of attacks," said George Burgess, director of ISAF.

"In certain geographic areas the decline is very severe. In other places, less so," he said.

"The areas that are overfished most quickly and easily are nearest shore. So, as a result, in many areas the population of larger sharks is very low in the near-shore areas where most people enter the water."

Burgess adds that falling shark populations could be just one of several factors influencing attack frequency.

Other shark specialists say that population numbers play a minimal role.

"I think it's a dangerous thing to try to correlate shark population numbers with attack statistics, because much more than the number of the sharks in the water goes into the resulting number of attacks," said Bob Hueter, director of the Mote Marine Laboratory's Center for Shark Research in Sarasota, Florida.

Hueter cites the example of the blacktip shark, which is responsible for many nonfatal bites on swimmers in Florida's waters.

"By all scientific assessments that population has been recovering over the last four or five years," he said.

"There's no reason to believe that their numbers are less at this point in time than they were five years ago. These animals were responsible for so many of the [Florida attacks] recorded every year, yet the numbers of recorded instances are dropping."

"In my mind it's due less to the size of shark populations than it is related to what people do," Hueter continued.

"Through the years one thing that has stood out clearly in terms of trends is that increasing human populations have put more people in the water."

ISAF's Burgess agrees that human behavior is perhaps the key factor.

The decrease in attacks could be due to fewer people in the water last year. Beachgoers are influenced by many variables that limit the number of beach days in a given season.

Tropical storms hammered Florida and other southeastern U.S. states in 2004 and 2005, reducing the number of people in the surf. Economic conditions may have also played a role, not to mention a drop in tourism in the post-9/11 era.

"In areas such as Florida there have been noticeable reductions in tourism, and that means less people entering the water," Burgess said.

"There have been low-contact years between sharks and humans in Florida, and that's reflected [in the data]."

Florida is a shark-attack hotbed, with huge importance for global shark-attack data. Trends in the Sunshine State are likely to significantly affect global statistics.

Beachgoers may also be getting smarter about when and where they enter the water, experts say.

"I think the work that people have done since 2001 to get the word out about the realities of shark attack and the guidelines of when and where to swim is paying off," said Mote's Hueter. (See "Shark Attack Tips.")

"Avoid the time periods [near] dawn and dusk, when sharks feed," Burgess added. "Don't swim near fishers or bait, or if you see sharks."

"If people followed these guidelines, we could probably cut down shark attacks by half," he said. That change would be welcome, but won't do much to change a person's chances of being attacked, Burgess says. "That's from an infinitesimal chance [of being attacked] to half of an infinitesimal chance."

North America Site of Most Shark Attacks
A closer look at the data reveals that 64 percent of 2005's attacks occurred in North American waters—continuing a trend of recent years.

U.S waters, including Hawaii, saw 38 attacks. Australia had ten and South Africa four. The Bahamas, Fiji, Mexico, South Korea, St. Martin, and Vanuatu each reported a single unprovoked attack.

Florida remained the top U.S. shark-attack spot, with 18 attacks last year. Additional U.S. incidents occurred in South Carolina (five), Texas (four), Hawaii (four), California (three), North Carolina (two), New Jersey (one), and Oregon (one).

Some activities, such as surfing and windsurfing, place humans at greater risk of attack. The popularity of such water sports may partially account for the increasing attack frequency seen over the past century. In days gone by, seaside recreation was commonly limited to wading.

In 2005 surfers and windsurfers were involved in 54 percent of the attacks in which victims' activities at the time of attack are known.

Swimmers and waders accounted for only 37 percent, though many more people swim or wade than surf or windsurf. Divers and snorkelers were involved in just 7 percent of the incidents.

Related Article:
World shark attacks dipped in 2005

Source: news.nationalgeographic.com


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