Alarm over the biggest ship ever planned to fish Australian waters has spilled into direct action, with the supertrawler Margiris locked down by Greenpeace.

Climbers and divers are preventing the 9600-tonne ship from leaving the Dutch port of Ijmuiden to begin the journey to Australia, the environment organisation said.

"At 0300 AEST activists put a chain around the ship's propeller, and two climbers are currently hanging on the cables between the ship and the quay, to prevent the ship from beginning its journey to Tasmania," Greenpeace said.
Advertisement: Story continues below

The Dutch-owned ship is being re-flagged to Australia ahead of its scheduled introduction within weeks, according to joint venturers Seafish Tasmania.

“Wherever this ship has gone it has destroyed fish stocks and ruined fishermen's livelihood," said Nathaniel Pelle, Greenpeace Oceans Campaigner.

"Along with a broad cross-section of the community that has declared the Margiris unwelcome, we will be ramping up efforts to stop it doing the same in Australian waters”

Seafish wants to use the Margiris to fish for a quota of 18,000 tonnes of mackerel and redbait, ranging from waters off New South Wales, south around Tasmania and across to the Great Australian Bight.

The 9600-tonne vessel is more than twice the size of the previous largest ship licensed to fish in Commonwealth waters. The 4400-tonne Ivan Golubets briefly fished deep southern waters in 1992, the Australian Fisheries Management Authority (AFMA) said.

Seafish director Gerry Geen said the AFMA-set quota was estimated to be five per cent of the total Australian fishery for so-called "small pelagic" fish.

"It's not the size of the boat that matters, it's the size of the quota," Mr Geen said. "The normal process is under way now for Margiris to be registered as an Australian vessel. Seafish Tasmania aims to start fishing in August."

Opponents say that such large scale catches will drastically affect local fisheries based on larger fish that depend on the small pelagics. The high protein fish are destined for human consumption in West Africa, where the Margiris is claimed by Greenpeace to have plundered local fisheries.

Independent Federal MP Andrew Wilkie said: "The approved quota is not broken down into smaller limits for specific areas, which means the trawler could plunder our richest fisheries."

Mr Wilkie joined the Greens in calling for the Margiris venture to be rejected, as celebrities encouraged a growing online petition against it.

Singer Guy Sebastian on Twitter called for fans to join to the petition that has been gaining about 1000 signatures a day.

"They are going to wipe out 18,000 tonnes annually of small pelagic batfish, all going overseas," Sebastian tweeted. "Hugely affects our marine ecosystem."