The waters around the Kermadec Islands are home to the world's largest population of spotted black grouper.

Maori have launched legal action that could sink one of the world's largest ocean sanctuaries.



Te Ohu Kaimoana, the Maori Fisheries Trust, has filed proceedings at the High Court in Wellington to prevent the Government establishing the Kermadec ocean sanctuary, north-east of New Zealand.



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The sanctuary, announced by Prime Minister John Key in a headline-grabbing speech to the United Nations, would close off 620,000 square kilometres to fishing and mining.



Massey University marine ecologist David Aguirre said it would be a tremendous embarrassment if the sanctuary was overturned, "given the praise our nation and our government has been receiving around the world".



But Te Ohu Kaimoana (TOKM) chairman Jamie Tuuta said the proposal rode roughshod over Maori interests.



Tuuta said people might assume from the proceedings that "Maori are against sanctuaries", which he said was not the case. "Maori are conservationists."

The trust wanted the Crown's 1992 Sealord fisheries settlement with Maori to be considered, however. Tuuta said it provided Maori with customary fishing rights and guaranteed the trust would be fully consulted "on matters relating to the management of fisheries and ecosystems".

That had not occurred with the Kermadec sanctuary proposal, he said.

MALCOLM FRANCIS A humpback whale and her calf migrating through Kermadec waters.

Environment Minister Nick Smith said the trust could pursue a legal challenge if it wanted to, but the Government was committed to the sanctuary.

"There has been no fish caught in the area by TOKM in more than a decade so any claim that their rights have been infringed is very theoretical.

"It is also significant that the two iwi connected to the sanctuary support its creation."

Auckland Museum head of natural sciences Tom Trnski has led four research trips to the Kermadecs. He said the area was special because there had been little fishing, even around its island coasts. "All the top predators are there in quite large numbers; sharks, spotted grouper, kingfish. Coastal New Zealand used to be like that 100 years ago but no longer."

The area provided a "baseline" against which more damaged marine environments could be measured, he said.

It would also be a "barometer of change" for global warming as more tropical species migrated there "which in the longer term will end up in northern New Zealand as well," he said.

The Government should also get serious about protecting areas around mainland New Zealand, he said.

Sea Shepherd New Zealand managing director Michael Lawry said, "the more sanctuaries the better".

Tuuta believed the Kermadec sanctuary could increase pressures on other fisheries.

There was a lack of scientific research about the possible impacts, he said. "Many fish species migrate so they don't just stay in the sanctuary. The positive impact needs to be tested."

The legal action was about Maori rights, he said. "You can't summarily dismiss these rights ... unilaterally, which is essentially what has happened in this case."

Tuuta believed a date for the court hearing could be set this week.