It was in the middle of the night in bad seas when Gus Johnson last saw his twin brother, Devin.

They were riding out rough weather on their fishing boat south of the Big Island — just the two of them — and had been taking turns tending the lines and sleeping.

Shortly after midnight, Devin was watching a DVD; Gus was going to grab some sleep.

When Gus awoke less than two hours later, at about 1:30 a.m. Friday, the DVD was still playing and Devin was gone.

By last night, Big Island authorities, the military and dozens of volunteers had searched more than 6,000 square miles of ocean with no sign of the 23-year-old Kona commercial fisherman.

Devin, described as a "good kid" who loved to surf and fish, apparently somehow went overboard into the treacherous night. A count found no life vests missing, said Barry Birdsall, a friend of the Johnson family who talked to Gus Johnson yesterday and detailed the events as Gus told them.

Big Island police said the Johnsons' boat was 60 miles south of Kona when Devin disappeared.

Birdsall said the 40- or 45-foot Kealea was on autopilot and battened down, standard practice in rough seas.

Upon discovering that Devin was gone, "Gus immediately stopped, turned on all the ship's lights and called the Coast Guard on a satellite phone," Birdsall said. "Then he went out on his own searching alone in the terrible weather. They're twins, you know. It just makes me cry."

Birdsall said at least 50 volunteers on five vessels, two airplanes and a helicopter were helping in the search. He said Big Island Air had donated the airplanes — "They wouldn't even talk to us about money. They said just find him." — and Paradise Helicopters had donated a helicopter. "It's great that we have so many kind, loving people here," he said.

Birdsall said he and other volunteers were out searching all day Friday and that waves reached 18 feet and winds were at 30 knots for part of the time.

"At 2 a.m. (Saturday) we had to come back in," he said.

He was out again yesterday on an airplane with eight passengers and conditions were better.

Devin and Gus Johnson are well-known commercial fishermen in Kona, said Kai Birdsall, Barry's wife. The Birdsalls live in North Kohala but used to live near the Johnson family in Waimea, she said yesterday. They have known the brothers for 10 years.

She said Devin Johnson was single and devoted most of his time to fishing and surfing.

"He's a good kid," she said. When the Johnson brothers aren't out on their boat, they live with their parents, Darryl and Kathy, and have an older brother Marcus, 25, Kai Birdsall said.

Barry Birdsall said Darryl, Gus and Marcus Johnson were all out on vessels searching yesterday.

"The Coast Guard and the Navy are working together" on the search, said a Coast Guard spokesman, Petty Officer Michael De Nyse. The Coast Guard launched a C-130 long-range search plane and an HH-65 rescue helicopter. The Coast Guard cutter Kiska, a 110-foot patrol boat with a crew of 18, joined the search.

"We're throwing every research asset we have at this," De Nyse said.

Also searching were air crews aboard a Navy P-3C Orion airplane and SH-60 Seahawk rescue helicopter from the Navy's HSL Squadron 37. Both are based at Marine Corps Base Hawaii at Käne'ohe Bay.

The search directed from the Coast Guard's 24-hour Honolulu Harbor command center had covered more than 6,000 square miles by last night.

Searchers reported deteriorating weather conditions with seas of 12 feet and winds from the southeast at 25 knots, the Coast Guard said.

Johnson is described as 5 feet 11, 160 pounds with brown eyes and brown hair.

Police ask that anyone with information on his whereabouts call acting Lt. Myra Iwamoto at 326-4646, ext. 281, or the Hawaii County police department's non-emergency line at 935-3311.