Tuesday's attack happened in the Pacific Ocean just north of the popular Mexican resort Ixtapa. Twenty-four-year-old Adrian Ruiz of California was surfing when a gray shark bit his thigh, leaving a 15-inch gash. He was rushed to a hospital, but died from loss of blood.
"Always had a smile on his face, always would cheer you up when you're in a bad mood," said Ruiz's friend Eric Griffin.
Ruiz's death comes just four days after 66-year-old David Martin was fatally attacked by a great white shark just north of San Diego.
Shark attacks in these waters are very rare.
"From 1900 to the present, we've had 11 fatal attacks along the entire Pacific coast of North America," said shark expert Ralph Collier. "
Not so in Smyrna Beach, Florida, where three surfers have been bitten in three days. The injuries were minor.
"It's the shark capital of the world. There's a lot of sharks out there. We just saw one a couple minutes ago jump out," said one Florida surfer.
Experts believe sharks mistake surfers and swimmers for seals and sea lions.
"They prey on things that look like humans, but we're not part of their natural diet," said Steve Blair, Aquarium of the Pacific.
Near San Diego, surfers held a memorial in the water, circling the spot where Martin was attacked. Many are already back riding the waves with a new respect for the sharks that share the water.
"It's their ocean -- we're not top of the heap, and we have to understand that," said local surfer Craig Williams.
Although shark attacks happen occasionally in Florida, experts say they are very rare in Mexico. In 2006, there was only one attack in Mexico, and it was not fatal.