Threat status: critically endangered
Found in: coastal waters of New Zealand's West Coast North Island
Did you know:
- Māui dolphins are a subspecies of Hector’s dolphins, the world’s smallest dolphin.
- They are also some of the rarest dolphins in the world.
- They can only be found on the West Coast of the North Island.
On the edge of extinction
A recent estimate of the Māui dolphin population indicated that just 55 individuals over one year of age remain.
Recent studies suggest the number of Māui dolphins has reduced since earlier surveys and may still be declining.
Like the kiwi, the Māui dolphin is an important part of New Zealand’s natural heritage. If we don’t take care of them, this endemic dolphin will be lost forever.
Hope for Māui dolphins
Big steps forward have been taken to help protect Māui dolphins. There has been a ban on set netting and trawling along part of the North Island’s west coast, and more stringent controls over petroleum and mineral prospecting and mining.
Read more about current protection measures and learn how you can help Māui dolphins.
Māui dolphin sighted on a 2009-2010 survey
Māui dolphin are the smallest of the world’s 32 dolphin species.
Māui and Hector's dolphins look different to other dolphins. They are the only New Zealand dolphins with a rounded black dorsal fin. Other dolphins usually have a sickle-shaped fin.
Māui dolphin have distinctive grey, white and black markings and a short snout.
Females grow to 1.7 m long and weigh up to 50 kg. Males are slightly smaller and lighter.
They are known to live up to 20 years.
Facts about Māui dolphins
Short lifespans and slow reproduction
Māui dolphins are particularly vulnerable to decline as they have short lifespans, and are slow to reproduce.
- They only live up to 20 years. This is a short lifespan compared to other dolphins and whales.
- Females have their first calf (baby) between 7 – 9 years of age.
- They produce just one calf every 2 - 4 years, making population increase a very slow process.
- Māui dolphins may only be able to grow their population by 2% a year. That means that a population of 55 can only increase by 1 individual per year.
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Māui dolphins navigate murky waters and hunt their prey with echolocation
Māui dolphins can “see” with sound
Like other dolphins, Māui use echolocation to find their food. They send out high frequency clicks that bounce off surrounding objects and fish. These echoes are interpreted by the dolphin as a detailed picture of its surroundings.
Echolocation is a powerful tool, allowing dolphins to see fish hiding under sand and navigate murky waters. Although Māui dolphins do not use this sonar ability all the time, which may be why the dolphins get caught in nets.
Māui dolphins communicate with clicks
Whereas other species of dolphin communicate with whistles, Māui and Hector’s dolphins use short, high frequency clicks.
They may also use a variety of body language to communicate, such as slapping their tail on the water or leaping into the air.
Māui dolphins probably change their companions often
Māui dolphins’ social lives
If you come across a group of Māui dolphins, it won’t be a nuclear family of the parents and the kids. They likely have a social structure similar to Hector’s dolphins, where group members commonly change companions.
Usually groups are sex segregated, meaning males form separate groups from females and their calves.
Diet and foraging
Māui dolphins feed on a variety of species of fish, such as red cod, āhuru, and sole. They feed throughout the water column, on both bottom-dwelling fish and free swimming prey.
Difference between Māui dolphins and Hector’s dolphins
Māui dolphins and Hector’s dolphins may look identical, but they are physically and genetically different from each other. Māui dolphins have larger skulls than Hector’s dolphins overall, and a longer, wider rostrum (this is the “snout” part of the skull).
Māui dolphins are thought to have been isolated from their more numerous relatives, South Island Hector’s dolphin, for 15-16,000 years. This was around the same time the North Island shoreline split from the South Island during the Pleistocene.
They used to be known as the North Island Hector's dolphin but since 2002 they have been classified as separate subspecies.
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Māui dolphins have black, rounded dorsal fins and a lighter back
Māui dolphin range, as determined by the 2012 Maui's Dolphin Risk Assessment (Currey et al. 2012). Green indicates a relatively high concentration of dolphins, whereas red indicates a lower concentration
Māui dolphins could once be found along most of the west coast of the North Island, from Cook Strait to Ninety Mile Beach. Today, they are found from Maunganui Bluff to Whanganui, and you’re most likely to spot one between Manukau Harbour and Port Waikato.
Māui dolphins are generally found close to shore in small groups. They are usually seen in water less than 20 m deep but may also range further offshore.
They use the mouths of the Manukau and Kaipara harbours, and are often seen just outside many of the other harbours on this coast.
Studies suggest that the dolphins use about 30 km of shoreline, and some individuals have been recorded moving nearly 80 km in under three weeks.
Māui dolphins’ use of harbours and their close inshore distribution means that the same waters we use for fishing and recreation are also their home.
Māui dolphins are threatened by both the natural and human-induced factors. The greatest threat to Māui dolphins from humans is accidental entanglement in fishing gear. Set nets, which are fixed in place in the water, are the biggest danger. Trawling, which involves dragging a net through the water, may also pose a risk.
Because of their small populaton size, Māui dolphins are also susceptible to natural threats like disease. In particular, a disease called Toxoplasmosis has been found as a cause of death in several Hector's and Māui dolphins.
Find out more about threats to Māui dolphins
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Māui dolphin mother and calf
Current protection measures
The decline of the Māui dolphin has resulted in multiple protection measures on the West Coast of the North Island. A Marine Mammal Sanctuary has been put in place from Maunganui Bluff to Oakura, and restrictions to set nets and trawling occurs in much of the Māui dolphin's range.
Read a summary of protection measures and view a map of protected areas
Call if you see a rounded fin on the North Island
You can help - report sightings
Māui dolphins may seem far removed our lives on land, but there is still plenty you can do to help them.
In addition to staying engaged in governmental decisions and caring for the marine environment, we need beachgoers and boaties to report sightings so we can better understand their range. This will provide evidence to make the best decisions for Māui dolphin conservation.
Firing a biopsy dart during a Māui dolphin research survey
If you think you have spotted a Māui dolphin, call the 0800 DOC HOTline (0800 362 468).
Find out more about reporting sightings and other ways you can help Māui dolphins
Read stories about DOC's work
DOC is involved with numerous stakeholders and conducts a wide range of work concerning Māui dolphins.
Much of this work is influenced and guided by the Hector’s and Māui Dolphin Threat Management Plan, and the recent review of the Māui dolphin component.
Research on Māui dolphin
There is still a lot that we don’t know about Māui dolphin, including:
- if the population recover, and how quickly
- how they will be affected by the increasing use of their home range by humans, eg marine mining, seismic surveying, marine construction and coastal development
- if there is the potential for interbreeding between Māui dolphins and South Island Hector's dolphins
- DOC surveys in 2010 and 2011 found that there were at least two South Island Hector's dolphins swimming among the Māui dolphins
- While there is no evidence yet of interbreeding, if they did this may provide Māui dolphin with a much-needed boost by increasing their genetic diversity.
The Department of Conservation, together with university researchers and conservation groups, is seeking answers to these questions using a range of research methods and techniques. You can help with this research by reporting sightings of Māui dolphin.
Get in depth information on what DOC is doing to help save the Māui dolphin
Timeline of research and protection events
Review of the Māui dolphin Threat Management Plan
Much has happened since the Māui dolphin was declared a subspecies in 2002.
Follow the conservation story of the Māui dolphin and find out about crucial events, documents, and legislation that have affected Māui dolphins from 2002 to present.
Māui dolphin timeline of research and protection
DOC and others have published much information on Māui dolphins.
Find selected publications, key conservation documents, and survey reports, including the Review of the Maui's Dolphin Threat Management Plan (TMP) and the Seismic Surveying Code of Conduct.
Māui dolphin resources
Download information in a brochure (PDF, 5,570K)
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