Gangs of Californian surfers are apparently turning violent in a bid to protect their stretch of sand from outsiders.

As the sport's popularity increases, older surfers are having to compete for space with newcomers and are letting their frustrations show.

Robert Nisbet: All turning rather nasty

A growing number of surfers are being verbally or physically attacked, leading local media to dub the phenomenon "surf rage".

"You get a bunch of people out where someone else lives and they feel they should get the first chance at the waves that are at their local break," said Jim Light, of environmental group Surf Rider.

"The locals have grown up there, they go there every weekend and they get upset when people from outside come in and steal their waves," he added.

Jim Light: Locals upset when someone steals their wave

Veteran surfers Chris Jones and Steve Fisher have experienced surf rage at first hand.

"They'll gang up on you, cut you off, verbal abuse. I've never been threatened physically but verbally," said Mr Jones.

Mr Fisher reports fights, slashed tyres and rocks thrown off cliffs at surfers.

In one incident surfers were arrested for assault with a deadly weapon - a surfer speared the person in front of him with his surf board.

But it helped campaigners convince a sceptical police force that surf rage attacks are becoming more frequent, said Mr Jones.

Turning the tide

An Open Wave Act, giving everyone the right to surf wherever and whenever they want to, has now been proposed.

It will be put to a state-wide vote later this year, but there are fears that it will not be enforceable.

"People don't generally care too much about what surfers do in the water anyway. I'm sure they're not going to station a policeman at every break just to watch and see what's going on," said Mr Jones.

And in Washington, Congress will consider whether to classify surf rage attacks as federal hate crimes.

However, Jim Light is confident peaceful protests along the California coastline will eventually defeat the bullies.