The US National Oceanic and Atmospheric Agency has added the Māui's dolphin to its endangered species list.

The United States' National Oceanic and Atmospheric Agency (NOAA) has added the Māui's dolphin to its endangered species list.

It has also added the South Island Hector's Dolphin to its threatened species list. Both now come under the country's Endangered Species Act.

The decision has been labelled as "extraordinary" by the University of Auckland's Doctor Glenn Simmons, a fisheries expert.

DELWYN DICKEY A Māui's dolphin pictured offshore near the Manukau Harbour during a survey of the species. (file photo)

In New Zealand, the endemic dolphins are listed as critically endangered and endangered, respectively. Despite that gill netting and trawling - fishing methods known to be the number one threat to the dolphins - are still permitted in their habitats, experts say.

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Simmons said the move should signal to the government that US authorities are "dissatisfied with the measures they have taken [to protect the dolphins]".

SUPPLIED/PETER BEECH Hector's Dolphins swim under a boat. (file photo)

It suggested the US didn't have any faith in the NZ Government's efforts.

"It's big, because the US is a big friend [when they are] prepared to wave a big stick, it has ramifications."

But a spokeswoman for Seafood NZ said "the US move has no immediate implications to the current protection measures in place in NZ."

JAMES PASLEY/STUFF University of Auckland research fellow and fisheries expert Glenn Simmons says the National Oceanic and Atmospheric Agency's decision to list the dolphins as endangered and threatened is "extraordinary". (file photo)

NEW ZEALAND GOVERNMENT 'ON NOTICE'

Greenpeace executive director Russel Norman called NOAA's move "very significant".

"NOAA... have basically put the New Zealand Government on notice. [The Government] has failed to protect Hectors or Māui's dolphins. We still don't have full protection in their habitats."

UNIVERSITY OF AUCKLAND/SUPPLIED Māui's dolphin are distinguishable from other dolphin species by their rounded dorsal fin and small body. (file photo)

The International Whaling Commission had called for the banning of gill netting and trawling in Māui's dolphin habitats.

New Zealand's Government had effectively "given the finger" to the commission over the issue, he said.

The Seafood NZ spokeswoman said: "Vast areas of Hector's and Māui dolphin habitat are closed to trawling and set net fishing which has greatly reduced the risk to these species. MPI's latest scientific risk assessment for marine mammals confirms that fishing poses relatively little risk to these species.

HAGEN HOPKINS/GETTY IMAGES Greenpeace Executive Director Russel Norman says the Government's failure to protect Māui's dolphin was a "national disgrace". (file photo)

"Despite this reduction in risk, the Seafood industry is working hard to ensure that our fishing is dolphin-safe.

"We are investigating new fishing practices and two of New Zealand's major fishing companies, Moana NZ and Sanford, have joined with WWF–New Zealand to release a Maui Dolphin Protection Plan which will end coastal set netting in Maui habitat by the end of this year and remove conventional trawling methods from the Maui habitat by 2022."

But Simmons said there had "always been a bit of contention about how big the Māui's habitat is."

SUPPLIED Dead Hector's dolphins caught in a net.

The Ministry for Primary Industries was involved in a range of efforts to protect the two species, its website said.

In 2007, The Ministry of Fisheries (now MPI) and the Department of Conservation (DOC) released a Threat Management Plan for the dolphins. It was reviewed in 2012 and 2013, and another review was scheduled for 2018.

DOC had established marine mammal reserves in Hector's and Māui's dolphin habitats.

Efforts to protect the dolphins included closing some areas to fishing and restricting certain types of fishing in different areas.

There also had be a government observer on any commercial set net vessel operating within two to seven nautical miles from the Taranaki coast between the Waiwhakaiho River and Hawera.

MPI said it had also been increasing observer coverage on trawl vessels operating north of that area – between Maunganui Bluff and Pariokariwa Point.

The University of Otago's professor Liz Slooten said while the Government considered it was doing enough, the international science community did not.

"Here's an international entity [NOAA] that has looked very carefully at all the science and says 'come on New Zealand, you need to pull up your socks and do something here to protect, in particular, Māui dolphins."

A BAN ON FISH EXPORTS TO THE US?

On January 1, the US passed a final rule of its Marine Mammal Protection Act (MMPA), meaning it could stop imports of fish from fisheries in other countries where marine mammals were bycatch.

The ruling wouldn't come into effect for five years, but an emergency clause could potentially enact a ban for endangered species - like Māui's dolphin - sooner. The reality of the MMPA ruling being enforced for New Zealand was unclear yet.

Slooten said MMPA meant countries would have to prove marine mammal bycatch was sustainable.

"In the case of Māui's dolphins, no bycatch is sustainable because there is only 63 dolphins."

Simmons said the likelihood of the US enforcing the ban on fish exports from New Zealand was a "real possibility".

Snapper fishing off the North Island's west coast - the Māui's dolphin's habitat - was a fishery that could be affected, he said.

Norman said the likelihood of a ban was unknown.

"What's plainly the case is that the New Zealand Government has failed to protect the Māui's dolphin and that is now getting a lot of international attention in the United States, at the International Whaling Commission.

"The fact that we have the most endangered dolphin in the world and we have not protected it... is getting the kind of international attention it deserves. It is literally a national disgrace."

Slooten expected the biggest impact would be "reputational​" and harm the clean, green image of products from New Zealand.

HOW ARE MĀUI'S AND HECTOR'S DOLPHINS DOING?

In New Zealand, Māui's and South Island Hector's are listed as critically endangered and endangered, respectively.

Only an estimated 63 Māui's dolphins more than one year old exist, and the species is only found in water off the North Island's west coast. Hector's dolphins are mainly found in water around the South Island.

The Hector's dolphin population was between 12,000 and 18,500, research published in 2016 showed.

Previously, full closure of gill net and trawling fisheries within the range of Māui's dolphin has been sought by the International Whaling Commission scientific committee.

Stats NZ figures showed that between 1921 and 2015, entanglement in fishing gear accounted for up to 71.4 per cent of the 301 Hector's and Māui's dolphin deaths for which a cause of death was determined.

The MPI said: "Fishing is the greatest known human threat to Hector's and Māui's dolphins - responsible for about 75 per cent of reported deaths with a known cause."

Slooten said the latest MPI report said for Māui's dolphin alone, about 95.5 per cent of the human impact was from fishing.