Hector’s and Maui’s dolphins
Marine life
Hector’s and Maui’s dolphins are among the world’s smallest marine dolphins. They are found only in the inshore
waters of Aotearoa/New Zealand.
Recent research has shown that there are two subspecies of Hector’s dolphin; Maui’s dolphin (the North Island
sub-species Cephalorhynchus hectori maui) and the South Island Hector’s dolphin (Cephalorhynchus hectori
hectori). These two sub-species are physically and genetically distinct from each other.
The small population of about 100 Maui’s dolphins is thought to have been isolated from their more-numerous
(c. 7000-strong) southern relatives for thousands of years.
Hector’s dolphins are classified as ‘nationally vulnerable’, while Maui’s dolphins are listed internationally as
‘nationally critical’. They are the rarest marine dolphin sub-species.
Hector’s dolphins are named after Sir James Hector, a former curator of the New Zealand National Museum.
Maui’s dolphins are named after an important character in many Mäori myths and legends. Hector’s and Maui’s
dolphins are known to Mäori by other names, including tutumairekurai, aihe, papakanua, upokohue, tukuperu,
tüpoupou and hopuhopu.
What do they look like?
Hector’s dolphins
MCU Wellington
Published by
Department of Conservation
Christchurch
2006
NS0045
They are the only dolphins in New Zealand with a wellrounded black dorsal fin. Their bodies are a distinctive
grey, with white and black markings and a short snout.
Adult South Island Hector’s dolphins don’t often
exceed 1.5 metres in length and weigh between 40
and 60 kg. Males are slightly smaller and lighter than
females.
Maui’s dolphins are slightly larger than their southern
counterparts, with adults growing up to 1.6 metres
long. Again, females are slightly larger than males in
this sub-species.
Where are they found?
Today Maui’s dolphins are found on the west coast
of the North Island of New Zealand. It is believed that
they were much more abundant and wide-spread
around the North Island in the past.
Hector’s dolphins are found around the coast of the
South Island but distribution is patchy. Populations
are concentrated between Haast and Farewell Spit in
the west, around Banks Peninsula in the east, and Te
Waewae Bay and Porpoise Bay/Te whanaga aihe in the
south.
There is no evidence of long
distance along-shore migration
of the species. The greatest
distance between sightings of the
same individual is 106 km apart.
Consequently there is thought to be
little inter-breeding of the southern,
eastern and western populations
and each has a genetically distinct
population.
Both sub-species appear to have
a relatively coastal distribution,
preferring shallow waters closer to
the shore in summer. During winter
dolphins are more dispersed and
have been sighted up to 18 nautical
miles offshore.
Maui’s dolphins are often seen in
water less than 20 metres deep but
may also range further offshore.
Fascinating facts about
Maui’s and Hector’s dolphin
• Both Maui’s and Hector’s dolphins are known to
live to a maximum of about 20 years.
• Like other dolphins, Maui’s and Hector’s use
echo-location to find their food. They send out
high frequency ‘clicks’ that bounce off surrounding
objects and fish, giving the dolphins a detailed
picture of their surroundings. This sonar is not
used all the time, which may be one of the reasons
why the dolphins get caught in nets.
• Females reach sexual maturity between seven to
nine years of age. They produce just one calf every
two to three years, making population increase a
very slow process.
•
Most females only have four or five calves in a
lifetime. Calving usually occurs between November
and mid-February, and calves stay with their
mothers for up to two years.
•
Traditionally, Mäori people watched dolphin
movements to predict the weather.
Threats
Dolphins and people have shared
our shores and bays for centuries. In
recent years, there has been a worldwide increase in awareness of marine
mammals and a greater desire to protect
them.
Set-net fishing poses a major threat to
Hector’s and Maui’s dolphins. Like all
marine mammals they need to come to
the surface regularly to breathe. If they
become tangled in set nets, they will hold
their breath until they suffocate.
Because these dolphins occur close
inshore, often in bays and harbours,
they are at risk of being injured by boats.
Newborn dolphins are particularly vulnerable as they
swim relatively slowly, close to the surface. Some have
been killed by boat propellers, when unwary boaties
have run them over.
Other potential threats to their survival include trawling,
marine pollution, disease and impacts of tourism and
aquaculture.
•
•
•
Set-net controls were introduced to Canterbury in
2002 and in west coast North Island in 2003.
•
Research and scientific studies continue to
increase our knowledge about each sub-species’
ecology, conservation status, life history, and
threats.
•
Improved management practices are continually
being sought for these dolphins in an attempt to
ensure their survival into the future.
How you can help?
• Avoid using set nets, particularly when you cannot
remain with your net. If you see dolphins in the
area, please remove your nets from the water.
•
Please don’t swim with the dolphins except with
authorised tourist operators. If swimming near
dolphins, avoid wearing suntan lotion or insect
repellent as chemicals can irritate dolphin’s eyes.
Do not try to touch dolphins.
•
If in a boat use a ‘no wake’ speed within 300
m of dolphins. Should you need to outdistance
them, you may increase your speed gradually to a
maximum of 10 knots.
•
•
Do not feed dolphins. Human food is harmful.
•
Co-operate with others so all may see dolphins
without putting them at risk.
•
Report sightings of Maui’s dolphins to the WWF
Sightings Network by phoning 0800 4 MAUIS
(0800 4 62847) or submitting a report on
www.mauisdolphin.org.nz  This information is
shared with DOC.
Keep their environment clean. Take your rubbish
home, and if you find any floating at sea or on the
coast, please pick it up.
•
If you find a stranded dolphin, contact your nearest
DOC office or police station as soon as possible.
DOC has a 24 hour emergency call out number
0800 DOCHOT line, 0800 36 24 68.
•
Contact the Ministry of Fisheries on 0800 4
POACHER (0800 4 76224) if you see set nets
being used within closed areas.
•
If you accidentally catch or harm a dolphin you
must report it as soon as possible to DOC or
Mfish.
What is being done?
If alive;
The Banks Peninsula marine mammal sanctuary
in Canterbury was established in 1988 primarily to
reduce set-net deaths of Hector’s dolphins in the
area
Keep the animal wet, but don’t pour water down its
blow hole
Keep the animal upright
Keep the animal shaded from the sun
The Marine Mammals Protection Regulations were
introduced in 1992 to control marine mammal
tourism activities
For further information
Visit the DOC website at www.doc.govt.nz.