MENDOCINO - Acting on a tip, state Fish and Game officers staked out and arrested a scuba-diving abalone poacher as he fled in a wetsuit, authorities said.

Larry St. Clair II of Potter Valley was caught at 5 p.m. Friday as he left a state park in Mendocino.

He was released from Mendocino County Jail on $40,000 bail.

Divers can buy a license to catch abalone from April 1 to Nov. 30 with a July break, but are not supposed to use scuba gear. St. Clair was arrested for diving out of season and selling the abalone commercially, which is illegal.

The tipster told officials that St. Clair had been selling the abalone in Chinatown in San Francisco.

"He actually admitted he had been doing this for 10 months," said Department of Fish and Game spokesman Steve Martarano. "The number of abalone he had been taking was in the thousands."

Martarano said officials watched as St. Clair, 31, dove in the water and stayed under for 50 minutes.

"During that time, he came up with 53 red abalone mollusks, which were shucked," Martarano said. "He had taken them out of their shells underwater, put them in a bag and was going to take them home."

Police confiscated his 2001 Dodge pickup, an inflatable boat, the abalone, extra oxygen tanks and ice chests. Martarano said law enforcement found another 40 abalone in St. Clair's home refrigerator.

Red abalone can fetch as much as $40 each and a black market for poachers is an ongoing problem, Martarano said. About 20 poachers have been busted since Nov. 30, for filching nearly 3,000 abalone.

"There's a whole network of buyers, sellers, wholesalers and delivery men," he said.