By james art 
The 61-year-old man was surfing off Maui’s Waiehu Beach Park on Friday morning when he was bitten by a shark.
Police officers who arrived at the scene first tried to control the bleeding with tourniquets.
His right leg was “completely severed just below the knee,” Maui County said in a statement.
The man was alert while being treated on shore and then taken to Maui Medical Center in critical condition.
The man said he did not see the shark approach, authorities said.
The incident prompted officials to close the beach park. Authorities warned people to stay away from water in the area.
A public advisory to stay out of water for one mile in each direction of the incident will be in effect until at least noon Saturday local time. The warning will be extended if there is a shark sighting in the area.
Maui Fire and Ocean Safety officials patrolled the waters using rescue vessels and a drone. State officials provided shark warning signs and helped cordon off the area.
No details were given on what kind of shark it was.
In June, famous surfer Tamayo Perry was killed in a shark attack while surfing off the north shore of Oahu.