California game wardens can stop and question motorists leaving hunting or fishing grounds even if they have no reason to believe the person has done anything illegal, the state Supreme Court has ruled.

The need to protect wildlife for future generations outweighs the minor intrusion of a vehicle stop on a participant in a regulated activity like hunting or fishing, the court said Monday in a unanimous ruling. The opinion was written by Chief Justice Tani Cantil-Sakauye, her first since joining the court in January.

State law also allows wardens to see motorists' hunting or fishing licenses and any game they have caught, and to search any receptacles that might hold fish or game, Cantil-Sakauye said. She said the wardens' actions would be for the purpose of conservation and not criminal law enforcement, which would require a search warrant or probable cause of wrongdoing.

The lawyer for a San Diego man charged with catching a lobster out of season said he may appeal to the U.S. Supreme Court.

The ruling gives new powers to "a special sort of state police officer," said Matthew Braner, a deputy county public defender. By the same reasoning, he said, police might be allowed to stop and question anyone leaving a bar as part of an effort to prevent drunken driving.

But Deputy City Attorney Jonathan Lapin said the U.S. Supreme Court has ruled routine police detentions outside bars unconstitutional because they are law enforcement actions and because authorities have other ways to catch drunken drivers.

By contrast, Lapin said, game wardens "really couldn't be doing their job" without the power to detain people who have recently been hunting or fishing, activities that rarely show outward evidence of lawbreaking.

A warden patrolling a San Diego fishing pier through a telescope one night in August 2007 saw Bouhn Maikhio reeling in either a lobster or a fish and putting it in a black bag.

Believing Maikhio might be catching lobster illegally, the warden stopped his car three blocks from the pier and questioned him. When Maikhio denied having any fish or lobster, the court said, the warden searched the car and found the bag containing a California spiny lobster, which he returned to the water.

A Superior Court judge and a state appeals court dismissed the misdemeanor charge of catching the lobster out of season, saying the warden was not entitled to stop the car without evidence of lawbreaking. The state's high court disagreed.

A warden who has reason to believe someone has recently been hunting or fishing can stop a car and question the driver, who has "chosen to engage in the heavily regulated activity" and thus has a "diminished reasonable expectation of privacy," Cantil-Sakauye said.

The ruling in People vs. Maikhio, S180289, can be viewed at links.sfgate.com/ZKZZ.