Swimmers are being warned to avoid the area near Aquatic Park in San Francisco Bay or swim there at their own risk after the second swimmer in two days was bitten by a sea lion in attacks considered unusual.

A man was transported with non-life-threatening injuries to a trauma center Friday morning after the second sea lion attack, according to KTVU.

More details were known about the first attack that occurred at 1:45 p.m. on Thursday.

A 56-year-old man was swimming in the bay when a sea lion bit him on the arm after he failed to scare it away by splashing it and yelling at it, NBC Bay Area and KTVU reported.

Fortunately, people on a nearby sailboat witnessed the attack, went to the man's aid and called the Coast Guard.

The man suffered a "severe extremity injury." He was taken to Pier 45 where San Francisco policeman Michael Reiter applied a tourniquet; paramedics treated him further before he was taken to the trauma center at San Francisco General Hospital. He was reported in stable condition.

"I mean, the boat saved his life," Reiter told NBC Bay Area. "If the boat hadn't been there, who knows what would have happened. They had rented the boat for the day, I believe, and they were on their way back when they saw this."

Aquatic Park Historic District is the site where two swimmers were bitten by sea lions. Photo: Courtesy of Wikipedia Commons

Dave Schreibman, who was swimming in the bay, saw the aftereffects of the attack.

"I saw a sailboat with a wounded swimmer on it," Schreibman tod NBC Bay Area. "They were waving at me and screaming at me to not go out there. The wounded swimmer had deep puncture wounds in his upper arm, and there was blood running down. There was a Coast Guard there, too."

Dr. Claire Simeon, a veterinarian for the Marine Mammal Center, told San Francisco Patch that bites from sea lions are unusual, adding that over a three-year period, only 10 bites or scratches had been reported in waters off San Francisco.

But recently, swimmers have increasingly been encountering threatening sea lions in this area.

"It's happened like a few times over the past few days," Sergei Khorochev told NBC Bay Area. "One guy on the sound told us that he was swimming, and he got bumped like five times by the sea lion, right here in the cove."

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