Australian endurance swimmer Chloe McCardel has ended her attempt to swim from Cuba to Florida after 11 hours in the water after she was stung by a jellyfish.
Her support team released a statement saying that Ms McCardel on Wednesday night stopped her effort to become the first person to swim across the Straits of Florida nonstop without a shark cage "due to a severe debilitating jellyfish sting".
It said she had been taken on to one of her support vessels and was sailing to Key West. She would need 24 hours to recuperate, it said.
Diana Nyad, an endurance athlete who failed three times to make the same crossing and has said she would like to take another shot this summer, tweeted her commiseration. "It's a tough night for Chloe McCardel, a superior swimmer and an exemplary spirit," she wrote.
Ms McCardel, a 28-year-old from Melbourne, had hoped to complete the swim in about 60 hours. Before starting out from Cuba in the morning, a smiling, upbeat Ms McCardel had arrived in a pink 1950s Chevy convertible at a rocky jetty in western Havana
"As confident as I can be. I think it's all going to work out well," she said. "It'll be tough, though."
She then jumped feet first into the water at 10am local time, with her goal, the Florida Keys, a little more than 100 miles to the north-east of Havana.
The strait has been busy for the last three summers, with fellow marathon swimmers Ms Nyad and Penny Palfrey making four failed attempts at the crossing between them since 2011.
"It is the hardest swim in the world today," Ms McCardel had said on Tuesday at a news conference. "No one has been able to achieve this. It's possibly harder than winning the World Cup or getting a gold medal."