More than 4000 people converged on a beach at Perth on Saturday to protest against a plan by the Western Australian government to cull sharks.
The state government last month announced a tender for professional fisherman to catch and kill great white, tiger or bull sharks.
Fishermen would set lines 1km from the shore of selected beaches and would target sharks over three metres in length.
The ABC reports the measure is in response to seven fatal shark attacks in three years.
Environmentalists argue there is overwhelming evidence that killing sharks will not prevent attacks.
They say other measures such as helicopter patrols and the tagging and tracking of sharks are more effective.
The culling tender closes on Sunday.