UPDATE: Firefighters were called after a protester locked herself to the top of a boat in an attempt to prevent drum lines being checked this morning.
Protesters plan to lock themselves to government boats this weekend to stop them checking drum lines off Perth beaches after the Department of Fisheries yesterday put in the first baited hooks and caught and released two undersized tiger sharks.
A woman used thumb locks to attach herself to the top of a Department of Fisheries boat at Fremantle fishing boat harbour about 5.45am today.
Firefighters were called to cut the locks. Police and an ambulance also attended.
The protest delayed the boat's departure by two hours.
Police said they were called to Fremantle about 4.30am after reports that a woman had climbed a fence at the boat harbour and locked herself on to a Department of Fisheries vessel moored at the harbour.
"Due to the way in which the lock device had been made, the woman was unable to free herself and the Department of Fire and Emergency Services were called in to cut her free from the lock device," police spokesman Samuel Dinnison said.
"The 19-year-old Fremantle woman was issued a move-on notice, and will be summonsed at a later date for trespass."
More than 6000 people are expected to converge on Cottesloe beach today for the biggest of seven protests against Colin Barnett's controversial shark-kill policy to be staged across WA.
Ten baited hooks - the first of up to 36 to be set off the metropolitan area - were dropped about 1km off Leighton, Cottesloe, City, Scarborough, Trigg and Mullaloo beaches yesterday.
The department's officers, who were given the job of setting and monitoring the lines off Perth after private contractors who tendered to do the work received threats, set the first drum line off Leighton beach after they set sail from South Mole at daybreak.
The first shark, a 1.5-2m tiger, was caught shortly before midday off Cottesloe. It was brought aboard PV Hamelin and released with relative ease, but a second, bigger tiger shark proved to be significantly more problematic.
The shark, measuring 2.6m, became tangled in a drum line and a separate float, forcing the boat's crew to unravel the mess.
After several minutes, the shark was pulled on to the boat via a slipway before the hook could be removed and the animal released.
No sharks were killed because neither of those caught met the 3m size specified in the Government's catch-and-kill order.
The Weekend West was invited into the anti-shark cull protesters' headquarters in Fremantle to watch as they built metal thumb locks that they claimed they would use to "lock on" to Fisheries vessels at the weekend.
Protester Simon Peterffy said several of the group's marine response unit members were fasting in preparation for the long periods of time they planned to be attached to the boats.
Mr Peterffy would not reveal where or when they planned to swoop on the Fisheries vessels, but he said there would be many people involved.
"That way we will be able to hold the boats for as long as possible," he said. "In this situation there's a lot of passion and if they're in the right position, we'll be able to lock on for days."
Surf Life Saving WA warned swimmers at Cottesloe beach to be careful after the Fisheries officers released the 2.6m tiger shark 1km offshore.
The organiser of today's biggest protest, scuba diving instructor Natalie Banks, said she expected that the rallies, to be held at Cottesloe, Warnbro, Bunbury, Dunsborough, Coral Bay, Broome and Shark Bay, would be passionate but peaceful.
"It is an interesting time to have these drum lines put in," Ms Banks said.
"I think there is a lot of anger and horror now that we are seeing the smaller sharks being caught on the drum lines in the metro area."
Speakers at the Cottesloe protest will include Opposition Leader Mark McGowan, Greens leader Christine Milne, Greens MP Lynn MacLaren, Sea Shepherd Australia managing director Jeff Hansen, West Australians for Shark Conservation founder Ross Weir and shark author Hugh Edwards.
Ms Banks said protests were also planned for New Zealand and outside the Mining Indaba conference in Cape Town, South Africa, where Mr Barnett is delivering a keynote speech next week.
A police spokeswoman said officers would be at Cottesloe to monitor crowds, maintain law and order and assist with traffic management where necessary.
Ms MacLaren said dropping drum lines off Perth went "against what the community wanted" and would meet continuing resistance.
"Mr Barnett will still be able to hear the protests of 5000 West Australians from Africa, where he has conveniently disappeared to," she said.