June 1, 2008

La Nina May Be to Blame for Recent Shark Attacks

A shark expert in the United States said Friday that cooler ocean water temperatures as a result of La Nina might have caused the wave of fatal shark attacks off the Mexican coast in recent weeks.

According to George Burgess, director of the Florida Program for Shark Research, La Nina usually results in cooler than normal waters in the Pacific, and may have moved the boundary between cold and warm water closer to the shore, taking fish and their shark predators along with it.

"One of the factors we're investigating is if there are special oceanographic conditions that might have contributed to the attacks," Burgess told Reuters.

Burgess was investigating the attacks at the request of Guerrero state officials.

At least two people, a tourist from U.S. and a surfer, have been killed by the sharks in the past few weeks near the coastal town of Zihuatanejo. Four people were killed the last time Mexico's Pacific coast experienced a series of fatal shark attacks in 1972-1973.

Burgess and a Mexican researcher examined police and medical records and interviewed eyewitnesses, but said more research was needed before any conclusions could be reached. Burgess said he believes more than one killer shark may responsible for the attacks, likely bull sharks.

"Bull sharks are probably the species that we as humans need to fear the most because they live close to shore and inhabit the waters that we as humans most often visit," he said.

"The odds are very high that it is not a single shark," Burgess said, explaining that the size of the bites were different.  

Burgess estimates that the attacking sharks were large, ranging from 8 to 10 feet.

During a government meeting Friday, Burgess recommended having trained lifeguards at every beach, posting warning signs and conducting more scientific research about the region's sharks.

"I don't think people should be afraid. I think people should have respect for sharks, just as one respects any wild animal," Burgess said.