Witnesses identified the victim as Hoku Aki, 17.

Fire crews said Aki was body boarding for only about 5 minutes when the attack happened. He was 150 yards from shore at the time, police said.

Authorities said Aki was one of about five people who were in the water at the time.

The victim's left foot was bitten off just below the ankle, officials said. Firefighters said Aki was able to swim to shore on his own.

Jason Brown worked at a nearby surf shop. He said he heard the commotion from the beach.

"A lady came in quite frantic, saying that there was a young man attacked by a shark. She thought at the time and he was 30 feet off the shore and he was surrounded by a big pool of blood," Brown said.

Beachgoers helped Aki out of the water and tended to him until paramedics arrived. Lifeguards and a vacationing nurse helped stop the bleeding, officials said.

Brown described what he saw when he reached the beach. "He (Aki) was lying there and you could tell by the shape of the towel around his leg that his foot wasn't there," Brown said.

He was taken to Wilcox hospital where he was last reported in stable condition.

It's been raining on Kauai for about 24 hours and the ocean at Brennecke's is brown and murky. Previous attacks have happened under the same type of conditions, according to officials.

The last shark attack on Kauai happened in 1997. Teenager Michael Coots was bodyboarding on the west side of the island when he was attacked. He also lost a foot.