They broke a schoolteacher's ribs and pelvis - for daring to surf on their turf

They start with the 'stink eye' and can end up putting you in hospital. Edward Helmore visits the Bay Boys, Californian surfers prepared to guard their territory with violence

On the beaches of southern California, surfing is becoming a seething territorial battle. For decades, there has been "localism", where surfers of a particular beach have done their best to scare away outsiders with verbal harassment. This year is different.

Last week, two surfers were convicted of beating up a third during a surf contest last year. The victim, Richard Ensdorf, nicknamed Shark, suffered a separated shoulder and required 15 stitches when he was assaulted after floating into the competition's area.

His attackers, Lance Hookano, a world renowned longboarder, and Joseph Tudor, the father of another competitor, had paddled out to give Ensdorf a series of punches. They are now facing a maximum seven-year jail sentence.

The case, which has attracted intense discussion among the obsessive surf fraternity, has highlighted the bad blood mixing with warm waters in a sport perceived to be a peaceful communion with nature.

Amid the surf and spray of Lunada Beach, north of Malibu, the notorious Bay boys of Palos Verdes Estates have long held that the beach, where some of southern California's best surfing is to be found, is their turf. Access to the horse-shoe shaped bay is a trail down a 200ft cliff - an ideal place for the Bay Boys to ambush visitors. Word has it that if you're not a local, don't stop there if you see a certain purple van parked in the lot.

The surf gang fights start with some dirty looks (giving the "stink eye"), followed by spearing, or propelling your surfboard at an intruder. They also slash the tyres and break the car aerials of non-residents. This often ends in a punch-up.

In March, two surfers gave a primary-school teacher a broken pelvis, a lacerated liver and broken ribs after a dispute over a wave, and throughout the summer battles have erupted between surfers who use long boards and those, like Ernsdorf, who ride shorter boards on their knees.

"Everybody knows they should stay away from Lunada Bay because they'll get hassled," says Peter McCullon, 34, a Palo Verdes "local" who lives on an inheritance and spends his days surfing and travelling. Enthusiasts of the sport say the violence is due to overcrowding on California's beaches and the proliferation of surf competitions which force non-contestants to abandon the waves.

"Trouble starts when there hasn't been much surf and then a good break starts up. If 15 other guys suddenly show up, there's going to be strife,"says Stan Fujii. Even the mellowest guy will then use the "stink eye".

Palo Verdes police chief Gary Johansen believes a few arrests and convictions might stop the trouble. The Bay Boys, they say, are not really bad - they are the "trust-fund babies" who live in expensive houses and have nothing better to do than travel and surf. "These kids grow up in a very sheltered environment," he says, add- ing that perhaps the trouble would stop if another gang stood up to them. "They don't know what a bad guy really is."

The district's senator, Brian Bilbray, himself a surfer, says he has seen enough. "It's fascism on the water. What we've got is now is the aquatic version of gangs and their territorial battles."

This being California, the dirty business of wave rights is beginning to reach civil courts. A group of surfers from Torrance, a beach further up the coast, have filed a $6m lawsuit against the city of Palo Verdes for allegedly failing to protect outsiders from interference by the Bay Boys.

"Non-locals say the police have done nothing to thwart the Bay Boys because it suits the wishes of the residents to uphold the community's exclusivity and keep the bay free of the graffiti, pollution, trash, crowding and unruliness found at other surf beaches where a come-one, come-all attitude prevails.

Reverend Rick Yeomans, a former director of Surfers For Missions, a missionary project, says he had a tough-talking surfer "go off" on him recently ."As a surfer, I can understand that surfers do not want outsiders at their break. But as a Christian and a pastor, I think it's too bad that people are that way. I just asked the guy: 'Hey, what's your problem?'"