A long-distance swimmer is recovering after a rare shark bite early Tuesday morning during an open water swim from Santa Catalina Island to the Southern California mainland.

The victim, identified only as a man in his 50s, was bitten in the Catalina Channel, a crossing of 20 miles at the shortest two points between the island and mainland coast. The victim suffered minor cuts, injuries that are not considered life-threatening, according to fire officials.

A LAFD vessel met the crew of a follow-boat that had been monitoring the swim at about 1:30 a.m. in the middle of the Catalina Channel. The shark, which authorities said was described as a 3- to 4-foot white shark, nipped at the man’s leg and was not seen again by the crew.

The victim, whose injury had already been wrapped when the fire department vessel arrived, was transported to a hospital for treatment.

The cross-channel swim is part of the triple crown of open water swimming, a list that includes the English Channel and the 20 Bridges Swim off Manhattan Island.

“It’s a pretty popular swim for long-distance swimmers,” said LAFD boat pilot Shaun Corby. “This is a super-rare incident. I don’t know what the underlying circumstances were, but shark bites are pretty minimal here.”

Sharks often bite or nip humans out of curiosity, a means of investigating their surroundings with their sensitive mouths.

The odds of being bitten by a shark are relatively slim when compared to other injury and fatality risks. There were 89 documented shark bites in California waters between 1959 and 2010, including seven fatalities, according to the International Shark Attack File. There were 34 lightning-related fatalities from 1959 to 2016, according to the National Oceanic and Atmospheric Administration.

Between 2004 and 2013, there were 361 rip current-related fatalities in the United States, according to the U.S. Life Saving Association. There were eight shark bite fatalities during the same period.

Distance is one of only a few challenges for swimmers crossing the Catalina Channel, which is subject to fluctuating temperatures. Swimmers often target midnight starts to avoid strong afternoon winds and currents can be unpredictable.