On the edge of extinction
A recent estimate of the Māui dolphin population indicated that approximately 63 individuals over one year of age remain.
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 dolphin
Big steps forward have been taken to help protect Māui dolphin. 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.
Māui and Hector's are the only dolphins with a well-rounded black dorsal fin
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 and Hector’s dolphins look identical, although they are physically and genetically different – find out how to tell the difference.
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.
Māui dolphin 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 approximately 55 can only increase by 1 individual per year.
Māui dolphin 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 dolphin do not use this sonar ability all the time, which may be why the dolphins get caught in nets.
Māui dolphin communicate with clicks
Whereas many other species of dolphins communicate with whistles, Māui and Hector’s dolphins use short, high frequency clicks. These clicks are at such a high frequency, the human ear can't hear them, although the dolphins can!
They may also use a variety of other methods to communicate, such as slapping their tail on the water or leaping into the air.
Listen to this Māui dolphin recording (MP3, 156K) produced by Steve Dawson, University of Otago.
These clicks were originally at a frequency of around 125 kHz (the human hearing range ends at about 20 kHz) and were slowed down to 1/20th of the speed to make them audible.
Māui dolphins’ social lives
If you come across a group of Māui dolphin, 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 dolphin 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.
Māui dolphin and Hector’s dolphin may look identical, but they are physically and genetically different from each other. Māui dolphin have larger skulls than Hector’s dolphin overall, and a longer, wider rostrum (this is the “snout” part of the skull).
Māui dolphin range – green indicates a relatively high concentration of dolphins, red indicates a lower concentration
Māui dolphin 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.
Māui dolphin 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 dolphin 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.