WAILUKU, Maui — Diving gear and partial human remains indicating a shark attack were recovered yesterday from the ocean off Makena.

A lanyard and keys found on the remains were identified by a family member as belonging to Anthony Moore, 45, of San Jose, Calif., who had been missing since Thursday evening. It was not immediately known whether Moore was killed by a shark or perhaps drowned or died of other causes.

Coast Guard petty officer Michael De Nyse said Moore swam out alone from Makena Landing at 3 p.m. Thursday. When he didn't return, his wife contacted authorities at 7 p.m. and a sea, air and ground search was launched after police found Moore's rental car parked at the landing.

Yesterday at 8 a.m., kayakers on a Maui Kayaks tour found diving gear and some remains on the surface at a popular diving spot known as "Five Graves" or "Five Caves." Acting Fire Battalion Chief Jack Williams said Maui Fire Department divers went into the water and found more remains on the bottom at 11:30 a.m. about 500 yards from shore.

A Maui Kayaks spokesman declined to comment. The dive site features underwater caves and a large population of sea turtles. Williams said searchers did not see any sharks in the area yesterday.

Police said an examination of the remains at the Maui Memorial Medical Center morgue revealed injuries consistent with shark bites. An autopsy is scheduled for today, but because there are only partial remains, officials said it may be impossible to determine the cause of death.

"In a lot of cases like this, you can't be sure," said Randy Honebrink of the state Department of Land and Natural Resources and its shark response team.

As a precaution, the DLNR closed the coastline from the Kea Lani resort to Pu'u 'Ola'i to keep swimmers out of the water. A decision on whether to reopen the area will be made this morning, Honebrink said.

There have been two reported encounters between sharks and humans along the same South Maui coastline in the past two months. On Dec. 21, a San Diego man lost part of his left hand when he was bitten by a shark while swimming several hundred yards off Keawakapu Beach in Kihei. On Feb. 1, a kayaker reported being bumped by a large shark about a mile off Makena State Park.

The last fatal shark attack in Hawai'i occurred April 7, 2004, when Willis McInnis, 57, was bitten while surfing off Kahana in West Maui. Generally, there are an average of three to four shark attacks in state waters annually.

Tiger sharks are responsible for most of the attacks in Hawai'i, and Honebrink said the fearsome predator is also known as an eager scavenger.

But drowning is "absolutely" more of a threat to free divers than sharks, according to Carlos Eyles of Holualoa on the Big Island. Eyles, 64, has been free-diving for more than 50 years, starting as a big-game spearfisherman but now working as an underwater photographer.

He said there are two types of free divers: performance divers who see how deep they can go in one breath, and spearfisherman, snorkelers and other divers who also do not use air tanks.

De Nyse said Moore was a well-conditioned, athletic man who had taken up free diving. Moore reportedly was training to reach a depth of 100 feet, De Nyse said. He was using a snorkel and regular swim fins when he went out Thursday, officials said, not the long-blade fins favored by many free divers to gain extra propulsion.

Eyles said 100 feet is a relatively easy depth for an experienced diver.

"Like everything else, it can be dangerous but it doesn't have to be. The real danger in it is that people don't understand their limitations and they exceed them," he said. "And if you're diving alone and you exceed your limitations, you're asking for trouble."

He said performance divers "black out all the time" but there is usually a safety diver nearby to help in an emergency.

"It's easy to drop down, and when you get to 100 feet and you turn around and you don't have big lungs or big fins, it's a fight to go up because the pressure is too great," Eyles said.

Kimi Makaiau of Hawai'i Skin Diver magazine said many free divers suffer "shallow-water blackouts" caused by lack of oxygen to the brain on their ascent to the surface, she said.

"It's a pretty extreme sport where we lose at least four to five divers a year to drownings," she said.

But Eyles also said he's had countless interactions with sharks during his dives. He said open-ocean species such as white-tips can be very aggressive, while tigers are generally wary and usually bump potential prey first to check for an easy target.

Shark experts and free divers agree that swimming alone is something to avoid. "People should always as much as possible stay close to where they can get help. But that's not in the nature of people," Honebrink said.

Police said Moore worked for Code Green Networks in Sunnyvale, Calif., which provides businesses with network security, content management and enterprise database technology.

The Coast Guard Air Station Barbers Point dispatched a C-130 plane and a HH-65 Dolphin helicopter to search the ocean off Makena Thursday and yesterday along with a 25-foot rigid-hull boat from Coast Guard Station Maui at Ma'alaea. The Maui Fire Department also sent a helicopter and had its boat and Yamaha WaveRunner in the water.

The C-130 dropped two radar beacons in what was estimated to be Moore's last known position to help determine a search pattern based on wind and ocean currents. Thursday's search was suspended at 11:35 p.m., with the effort continuing at first light yesterday. Yesterday's search was halted at 6:05 p.m. after word that the remains had been identified.

Reach Christie Wilson at cwilson@honoluluadvertiser.com.