Kansas visitor Dr. Ken Grasing said he was in four to five feet of water about 100 feet from the shoreline with his two sons Wednesday, when he saw a black shape appear and move quickly toward him off Hapuna Beach on Hawaii island.

Realizing it was shark, he struck it with his right hand on the side of its face and only later realized the shark had mangled his left arm.

“I was yelling,” said Grasing, interviewed Friday afternoon at Queen’s Medical Center.

“I was afraid the shark would attack them … I was yelling for help.”

Grasing said for whatever reason, the shark decided not to continue the attack.

Grasing, 58, a physician on vacation with his family for the first time on Hawaii Island, said the surgery to repair his left arm was successful and he plans to leave the hospital Saturday.