City lifeguards have been out this morning posting shark warning signs at the entrance to a surf spot known as "Crouching Lion's" and at Kahana Bay and Swanzy beach parks after a shark bit a surfer about 5 p.m. yesterday off shore from the Crouching Lion restaurant in Ka'a'awa.

City Emergency Services Department spokesman Bryan Cheplic said that since it was a confirmed shark bite incident, the signs will remain in place for 24 to 48 hours.

"We're asking the public to cooperate and avoid the area," Cheplic said.

The 40-year-old Kane'ohe man who was attacked by the shark was rushed to a hospital by city paramedics in serious condition.

Witnesses said the man suffered extensive injuries to his right thigh, ankle and fingers.

Cheplic said the beaches where the warning signs are posted are not staffed by city lifeguards.

But about 9:30 a.m. today, city Water Safety personnel will use personal watercraft to check the area for sharks, Cheplic said.