Sea lions are attacking swimmers in San Francisco Bay

Ashley May | USA TODAY

Since December, there have been four sea lion attacks in San Francisco Bay.

On Thursday, a sea lion attacked a woman at Aquatic Park, a popular spot for swimming along the northern waterfront. She was swimming when a sea lion bit her knee and tried to drag her under water, San Francisco Chronicle reports.

“She was bleeding pretty badly,” Lee Hammack, who was swimming nearby, told the Chronicle.

A retired paramedic on shore helped treat her until help arrived. The San Francisco Fire Department said the injury wasn’t life threatening.

In December, two people, one near Pier 45, were attacked with “serious bites” near the same spot in less than 24 hours, KRON 4 News reported. After those incidents, Aquatic Park Cove closed for at least four days. The station said another person was also attacked by a sea lion and almost bitten around the same time.

The attacks usually happen at low tide in the central Cove area, San Francisco Maritime National Historical Park said on Facebook.

"Please use caution: do not approach sea lions or seals, and consider swimming closer to shore and/or with a friend," the park said.

The National Oceanic and Atmospheric Administration advises swimmers to stay at least 50 yards away from free swimming sea lions.

Sea lion bites carry the risk of mycoplasma infection, also known as seal finger. If such infections, caused by bacteria living in sea mammals' mouths, are left untreated, people could lose fingers or limbs.

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