A young man sitting on an 8-foot surfboard in Oahu on Saturday was attacked by a shark, which bit his elbow and wrist, leaving him to bleed profusely.

"You kind of just saw blood everywhere," KHON2.com quoted surfer Ryan Hailstones, who was about 20 feet from the attack, as saying. “It was beautiful, glassy, really good waves and all of a sudden you hear someone yelling 'Help! Shark! Help!’”

"I just saw the fin going back-and-forth, back-and-forth while he's screaming trying to fight the shark off," he said.

Several surfers sprung into action, bringing the man, who is 23, to the shore and making a tourniquet from their surf leashes, reported KHON2.

Hailstones said the area, Laie Beach Park, also known as Pounders Beach, where the man was attacked tends to be rather empty, but that luckily it was crowded on Saturday.

"We safely got him to the beach and got through to one of these beach houses and called 911," he said. "We re-did the tourniquet when we got down there."

"It looked like he was losing blood really quick and the tourniquet really helped."

You kind of just saw blood everywhere. It was beautiful, glassy, really good waves and all of a sudden you hear someone yelling 'Help! Shark! Help!’ — Ryan Hailstones, witness

Witnesses told KHON2 that the victim was remarkably friendly after the ordeal, thanking those who had helped him. Paramedics took the man to the hospital, where he was in serious condition.

"He actually had a smile on [his face] getting into the ambulance and he was thanking everyone," Hailstones said. "He was a nice guy and I hope he recovers well."

In June, Hawaii’s director of the State Aquarium warned of multiple shark sightings in Oahu and Maui – not uncommon at a time of year when beaches attract more surfers and swimmers, reported KHON2.

Among the species spotted in the area are hammerhead and tiger sharks

"If they are hanging around an area, it's usually an indication there is food there,” said Andrew Rossiter, the State Aquarium director. “Perhaps something is dead beneath the water and the scent has attracted them there.”