海角大神

A mile-long stretch of Sunset Beach and Surfside Beach was closed Sunday after an Orange County Sheriff鈥檚 Department helicopter spotted three 10 to 12-foot sharks 150-yards off shore.聽聽

鈥淚t鈥檚 a precaution due to the size of the sharks and potential for aggressive behavior,鈥� Michael Diller, a lifeguard at the nearby Seal Beach, tells the Los Angeles Times.

The sighting comes a week after 52-year-old fitness trainer Maria Korcsmaros was bitten by a shark 15 miles south of Sunset Beach. Shark attacks have also been in the news across the world, including in Western Australia, where a 60-year-old diver and a 29-year-old surfer were both killed in separate fatal attacks last week.聽

鈥淭he evidence, some of it anecdotal, seems to be that there are significantly more sharks off our coastline,鈥� premier of Western Australia Colin Barnett told the Guardian. 鈥淭here seems to be more large sharks, particularly great whites, and they seem to be closer to the beaches.鈥�

Mr. Barnett's assumption is not wrong.聽

According to the International Shark Attack File, maintained by the Florida Museum of Natural History since 1958, 2015 saw 98 unprovoked attacks 鈥� the highest rate on record, surpassing the previous record set in 2000 with 88 attacks.聽

Researchers say there are two human-induced contributions to the increased attacks: rising human populations and rising ocean temperatures.聽

The National Oceanic and Atmospheric Administration (NOAA) reports nine of the 10 years with the warmest ocean temperatures have occurred since 2000. This long-term warming, says researchers, could shift the sharks鈥� range 鈥渁s much as 40 miles poleward per decade鈥� as they follow their prey鈥檚 migration away from the equator.聽The warming is certainly from human-caused climate change, say scientists, as 93 percent of greenhouse gas warming is absorbed by the world's oceans.

Also, rising human populations means that there are more swimmers venturing into the sharks鈥� territory each year.

鈥淪harks plus humans equals attacks,鈥� Dr. George Burgess, program director for the University of Florida鈥檚 Program for Shark Research, told UF News. 鈥淎s our population continues to rapidly grow and shark populations slowly recover, we鈥檙e going to see more interaction. We can and should expect the number of attacks to be higher each year. When we visit the sea, we鈥檙e on their turf.鈥�

In fact,聽Florida Museum of Natural History's shark website argues that given the rising number of humans in the water, the rate of shark attacks is declining.聽

While the total number of attacks each year has increased, they still aren鈥檛 as commonplace as many beachgoers might believe. For example, although 2015 was a record-breaking year in the number of attacks, there were six fatalities聽worldwide compared to the 11 deaths in 2000.

鈥淎lthough the headlines say 鈥榓ttack,鈥� these are really more of encounters, they are nonlethal,鈥� Dr. Neil Hammerschlag, director of the Shark Research and Conservation Program at the University of Miami, tells The Monitor in February. 鈥淚t鈥檚 important that we don鈥檛 create this hysteria that 鈥榮hark populations are on the rise, attacks are on the rise.鈥� It鈥檚 important to remember that these aren鈥檛 mindless killers. They are social animals and ecologically important and their populations are in trouble.鈥�

Some scientists and politicians say sharks face a greater threat to existence than humans.

An estimated 100 million sharks are killed globally each year, say a team of researchers at Dalhousie University in Canada in a 2013 statistical report. Between 6.4 to 7.9 percent of sharks of all species are killed annually, say the researchers, but no more than 4.9 percent can be killed to maintain population stability. Primarily, sharks die from being caught unintentionally as bycatch or they are killed for their fins to feed a Chinese appetite for shark fin soup.

Oceana reports that for every one human killed by a shark, on average, about 25 million sharks are killed by humans.聽