Media playback is unsupported on your device Media caption Protester: "We're better than killing wildlife in vengeance"

Thousands of people have been taking part in protests in Australia over a plan to kill large sharks.

The Western Australia government is set to install baited hooks off Perth's popular beaches in response to seven fatal shark attacks in three years.

But protesters say a cull is not the answer, and will only damage the sea's delicate ecosystem.

More than 4,000 people gathered for a demonstration at Perth's Cottesloe beach alone.

"Without the sharks there will be no future for humanity because they balance out the ecosystem and every living creature in the sea is really important," one protester said.

At a demonstration in Melbourne, one protester said: "We're better than killing wildlife in vengeance. We need to use the science that's there, to work with the science that's there, to learn to live with these creatures instead of culling them."

Sabotage fears

The WA government is planning to install some 72 baited hooks on drum lines one kilometre (mile) off the beaches by 10 January.

A contract to maintain and patrol the lines will be awarded to commercial fishermen in the coming days.

Any shark more than three metres long - which could include Great White, Tiger and Bull sharks - will be shot and disposed of.

The policy was settled upon following the death of a surfer and father-of-two in November.

Acting Premier Kim Hames insisted it would go ahead despite the protests, but took issue with it being called a cull.

"If it were a cull we would be out catching sharks the length and breadth of the state," he said. "We are concentrating on the areas where the public are frequent users."

And he warned of the bigger outcry if any protester tried to sabotage the drum lines, once operational. "What... if someone gets taken on the Rottnest Island swim for example, or a child at Scarborough Beach? Where will their protest be then?" he said.

But the protesters have vowed not to let up in their opposition to the plans. Further demonstrations are planned, and the Green Party says it is consulting its lawyers over the legality of the move.