Māui dolphin | WWF

Māui dolphin

Maui's dolphin, found off the west coast of North Island in New Zealand, has recently been identified as a subspecies of Hector's dolphin. This subspecies is the world's rarest marine dolphin – there are around 100 in the wild – and more than one human induced death every seven years seriously threatens its chances of recovery.
Maui's dolphin. rel=
Maui's dolphin.
© WWF / Will RAYMENT

Key Facts

  • Common Name

    Maui's dolphin ; Dauphin de Maui (Fr); (Sp)

  • Scientific Name

    Cephalorhynchus hectori maui

  • Status

    IUCN: Critically Endangered (CR C1, D)

    Read more

  • Population

    Around 63 adults

  • Location

    West coast of North Island, New Zealand

Together we can make the world's oceans safe for whales. 
	© WWF / Ogilvy Indonesia
Together we can make the world's oceans safe for whales. Learn more about WWF's work to protect whales.
© WWF / Ogilvy Indonesia

Safeguarding 'Te Ika a Maui'

The Māui dolphin was identified as the North Island Hector's dolphin (Cephalorhynchus hectori hectori) until 2002 when Dr Alan Baker described the sub-species Māui dolphin, based on genetic and skeletal differences. The name of the sub-species is based on the Maori indigenous name for the North Island, which is Te Ika a Maui.

The dolphin is also known as a Maui dolphin, Maui’s dolphin and the Māori name, popoto.

This animal is severely threatened by fisheries bycatch, and sensitivity analysis has predicted extinction within the next few decades unless all net fishing (including gillnet and trawl fishing) is banned within its range.

Māui need to be protected throughout their full range from harmful fishing practices and risky marine mining activities to ensure their survival. This requires a genuine sanctuary from Maunganui Bluff to the Whanganui river mouth, including harbours, out to 100 metres deep. Currently, less than half of their habitat is protected.

We can save Māui dolphins if the New Zealand government supports affected fishers to move to dolphin-friendly methods of fishing and extends the ban on set netting and traditional trawling fishing to cover all of their known range. Currently, less than half of their habitat is protected.

There is also a potential economic cost to letting Māui dolphins go extinct – it will damage the image of the NZ$1.56 billion fishing export industry, and New Zealand’s clean and green brand.
Maui's dolphins, North Island, New Zealand. 
	© Kirsty Russell
Maui's dolphins, North Island, New Zealand.
© Kirsty Russell

Physical Description

A rare and small cetacean, this dolphin is identified by a solidly built body with a gently sloping snout and a unique rounded (Mickey Mouse ear-shaped) dorsal fin.

Most of the Māui dolphins’ time is spent feeding. They have been observed to chase other dolphins, fight and jump. Young are reported to play with seaweed, blow bubbles and are involved with other 'games' which are considered to be important social behaviours.

Size

Adults measure between 1.2 - 1.7 m and weigh up to 50 kg.

Colour

The sides and back of this dolphin are light grey, with white "flames" reaching up along the sides of its body. The underside is whitish, while the face, flippers, the dorsal fin and tail are all black. There is a crescent-shaped black mark between eyes and blowhole.

Priority species

Whales and dolphins are a priority species. WWF treats priority species as one of the most ecologically, economically and/or culturally important species on our planet. And so we are working to ensure such species can live and thrive in their natural habitats.

Ecology and Habitat

Slow breeding rate = high survival vulnerability

The sub-species is found in inshore waters, including river mouths, estuaries, harbours and shallow bays, commonly within about 5 nautical miles of the shore.

Social Structure

Mothers and calves often travel in small nursery groups for protection.

This dolphin tends to occur in groups of up to five individuals, which may aggregate temporarily. Young are reported to play with seaweed, blow bubbles and are involved with other 'games' which are considered to be important social behaviours. Hector’s and Māui communicate using high frequency ultra sonic clicks at around 125 kHz.

Life Cycle

Calves live on their mother's milk for up to a year, although they learn to eat fish and squid after about 6 months. Females mature sexually at 7-9 years old.

Breeding
Like other small dolphins, Māui dolphins have a low reproductive rate - they breed just fast enough to replace the number of dolphins that die naturally. This slow birth rate means that Māui dolphins are struggling to recover from human-induced deaths.

Māui dolphins do not pair for life but mate frequently. Females start to breed aged 7-9 years. Females give birth to a single calf every 2 to 4 years, which is born with dorsal fins partly folded over and with fold marks along the bodies. The calf is large (50 - 60 cm) in proportion to its mother (only 1.2-1.4 m).

One female might have four calves in her 20-year life span. Māui dolphins may only be able to grow their population by 2% a year. That means that a population of approximately 55 can only increase by 1 individual per year.

Diet

Māui dolphins spend most of their time making short dives (90 seconds or so) to find fish on the sea floor. They also feed on fish and squid in mid water and sometimes close to the surface.
North Island West Coast scenery, near Raglan.  Habitat of Maui's dolphin (Cephalorhynchus hectori ... 
	© Tangi Corveler / WWF
North Island West Coast scenery, near Raglan. Habitat of Maui's dolphin (Cephalorhynchus hectori maui), smallest and rarest marine dolphin, native and endemic to New Zealand.
© Tangi Corveler / WWF

Population and Distribution

Population

The Māui dolphin population has plummeted from around 1500 in the 1970s, when deadly gillnets were widely introduced to New Zealand waters. The first survey of Māui dolphins in 1985 estimated the total population at 134. Māui dolphins were seen regularly in the Taranaki area in the 1970s. The population has plummeted from around 1500 in the 1970s, when deadly gillnets were widely introduced to their habitat.

A population abundance estimate released by the New Zealand Department of Conservation in 2012 revealed an estimated 55 Māui dolphins over the age of one remain. The 2016 government scientific survey estimated the population of the Critically Endangered dolphin at approximately 63 adults, with 95% confidence there are between 57 and 75.


Distribution

Māui dolphins are found in isolated pockets along the North West coast of the North Island. Their range is from Maunganui Bluff to the Whanganui River mouth, including harbours. They live in shallow coastal waters, up to 100 metres deep. This means they are at risk from inshore trawl and both commercial and recreational gill netting, which target the fish in this area. They live in small pods of 1 to 5 dolphins within 5 nautical miles of the coast.

During summer (October to March) they seem to venture closer to shore and are mostly seen within 1 nautical mile of the coast. It is thought that individuals remain within the same 60 km stretch of coast all their lives.

Major habitat type
Coastal waters

Biogeographic realm 
Australasia

Range States
New Zealand

Geographical Location
West coast of North Island

Ecological Region
New Zealand Marine
Major habitat type
Coastal waters

Biogeographic realm
Australasia

Range States
New Zealand

Geographical Location
West coast of North Island

Ecological Region
New Zealand Marine
Distribution of Hector's and Maui's dolphins in New Zealand. rel=
Distribution of Hector's and Maui's dolphins in New Zealand.
© WWF

What are the main threats to Māui dolphins

This dolphin is vulnerable to set net (gill net) and trawl fishing, marine pollution and debris, boat strikes, genetic bottleneck, mining, acoustic disturbance and coastal development.

Scientists estimate that over 95% of unnatural Māui deaths are caused by entanglement and drowning in gillnet or trawl fishing. In fact, just more than one human-induced death every seven years seriously threatens the chances of population recovery.

Since March 2001, seven dead Māui dolphins have been found. Five of these deaths were due to fishing, one was impossible to determine and one was because of natural causes.

A slow breeding rate and small population size have made of dolphin a Critically Endangered sub-species.

The Scientific Committee of the International Whaling Commission (IWC) acknowledged in its 2013 report, that Māui dolphins will decline to just 10 adult breeding females in six years and become functionally extinct in less than 20 years—unless their full range is protected from gillnetting and trawling.


Set net (gill net) and trawl fishing

Fishing with nets has pushed Māui dolphins to the brink of extinction. The dolphins get entangled in set nets and trawl nets and drown. Dolphins do not seem able to detect the fine nylon nets with echolocation and swim into them.

An expert panel convened by the NZ government in 2012 estimated that around 5 Māui are killed each year in fishing nets, a rate 75.5 times what the population can withstand.

They cannot swim backwards, so are unable to free themselves from the net. Since they cannot reach the surface to breathe, they drown within a couple of minutes. A set net ban is in place in part of the dolphin's range. The ban at this stage does not fully include harbours yet, even though dolphins have been sighted there.

In the South Island, Hector's dolphins have drowned in coastal trawl nets. It appears there is a risk to the Māui dolphin where there is overlap between dolphin habitat and trawl operations. Trawlers are still operating beyond of 1 nautical mile of the coast where dolphins continue to be vulnerable to bycatch.

We can save Māui dolphins if the NZ government extends the ban on set netting and traditional trawling fishing to cover all of their known range.

Marine pollution and debris
Dolphins like Māui which inhabit shallow coastal waters are vulnerable to the pollutants which humans allow into the sea. Chemicals from industrial waste, storm water and agricultural runoff like PCBs, DDT, dioxins and metals have been found in the blubber of Hector's and Māui dolphins. These pollutants bio-accumulate, which means they increase in potency as they move up the food chain. Māui dolphins are near the top of their food chain and these pollutants can be passed on to young dolphins through their mother's milk. High levels of exposure can cause loss of fertility and compromise immune systems in marine mammals. Another form of pollution which threatens Māui dolphins is solid rubbish such as plastic shopping bags which can be mistaken for squid and ingested, killing the dolphin.


Boat strikes

The propellers of motor boats pose a risk to Māui dolphins. Dolphin can suffer skin surface cuts to severe injuries from propellers. For example, in Akaroa Harbour, South Island, a Hector's dolphin calf died due to the direct impact of a boat strike.


Oil and Gas Exploration

Oil and gas exploration and activity in Māui habitat also poses a growing threat, with the New Zealand Government granting an increasing number of permits inside the dolphin's known range.


Genetic bottleneck

The genetic diversity of Māui dolphin has declined significantly over the last 100 years, raising concerns about a "genetic bottleneck". Their genetic diversity has been reduced from at least three lineages to one, making them susceptible to extinction from environmental and demographic change.
Hector's dolphin entangled  
	© Martin Abel
Hector's and Maui's dolphins, unable to detect the fine mesh of fishing nets, become entangled and die within minutes
© Martin Abel

What is WWF doing?

The International Whaling Commission (IWC) small cetaceans sub-committee report was released in July 2016, urging that the highest priority be given to eliminating the risk to Māui dolphins from entanglement in set nets and trawl nets before it is too late. For four years now, the IWC Scientific Committee has expressed increasing concern and recommended conservation and management measures regarding Critically Endangered species, sub-species and populations of cetaceans – with special focus on vaquita, Māui dolphins and the now extinct baiji.

This assessment that Māui dolphins need urgent protection across their entire range, is supported by science from the International Union for Conservation of Nature, the Society for Marine Mammology, and the government’s own risk assessment panel WWF-New Zealand is advocating for better protection of Māui dolphins – to work with government agencies, researchers and the fishing industry to determine the best conservation and management options. Together Possible!

WWF's objectives for Hector's dolphin and its subspecies Māui dolphin are that threats have been reduced to a level that allows the species to begin increasing in abundance, extending the range of Māui dolphin and reducing isolation of Hector's dolphin populations.

The majority of WWF's work on the protection of Hector's and Māui dolphins is carried out by WWF-New Zealand. Visit the WWF-New Zealand website for more extensive information on the species and WWF's efforts to bring them back from the brink of extinction.
The majority of WWF's work on the protection of Hector's and Maui's dolphins is carried out by WWF-New Zealand. Visit the WWF-New Zealand website for more extensive information on the species and WWF's efforts to bring them back from the brink of extinction.

How you can help

  • Visit the WWF-New Zealand website for a list of actions you can take to help save the Māui dolphin.
     
  • Support efforts to improve fishing gear by only buying seafood that is MSC certified. This can help to reduce the incidence of marine bycatch, which can kill Hector's and Māui dolphins and other marine life like turtles, whales, and seabirds.
     
  • Vote Earth by taking part in Earth Hour! As climate change is a growing threats for cetaceans (whales & dolphins) and other species, we need to send a message to our leaders that warming must be limited to under 2 degrees Celsius.
     
  • Spread the word! Click on the button to share this information with others via email or your favourite social networking service.

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Hector's dolphin

  • The Maui's dolphin (Cephalorhynchus hectori maui) is actually a sub-species of the Hector's dolphins (Cephalorhynchus hectori). There are three isolated populations of the Hector's dolphin around the South Island of New Zealand.

    Learn more about the Hector's dolphin

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