Activist group Sea Shepherd has failed to secure an injunction to halt a controversial shark cull policy in Western Australia, it said Thursday, vowing to fight on to prevent the killings. The group, best known for battling Japanese whalers in the Antarctic, applied for a judicial review of the decision, claiming it involves the unlawful killing of a protected species. Their argument questioned the validity of an exemption under the Environment Protection and Biodiversity Conservation Act which allows the state government to kill any protected great white, tiger or bull shark bigger than three metres (10 feet) in certain zones. But Western Australia Supreme Court Judge James Edelman ruled there was no reasonable grounds for a full hearing, and denied the request for an interim injunction to suspend 60 drum lines in place around the state coastline. "From an ecological and public safety perspective, Sea Shepherd Australia is very concerned about these drum lines remaining off the Perth metropolitan and southwest beaches," Sea Shepherd Australia managing director Jeff Hansen said. "Sea Shepherd Australia will continue our work to save the sharks of Western Australia, exploring all options available to us. We will not cease in our efforts until these cruel, barbaric, unsafe and environmentally unsustainable drum lines are removed permanently." The controversial policy to catch and kill sharks off popular west coast beaches was given the green light in January after six fatal attacks in the past two years. It aims to reduce the risks to water users and allows baited drum lines with hooks designed to capture large sharks to be set one kilometre (0.62 miles) offshore at busy Western Australian beaches for a trial period until April 30. Any shark longer than three metres (10 feet) snagged by the lines and deemed to be a threat -- including great white, bull and tiger sharks -- will be destroyed. Sixty-six sharks were caught in the first three weeks, according to the West Australian newspaper, although no great whites have been snared so far. The cull has angered conservationists, who claim the trial flies in the face of international obligations to protect the species. Sharks are common in Australian waters, and experts say attacks are increasing in line with population growth and the popularity of water sports.