New survey launched to estimate Maaui dolphin numbers
Wednesday, 12 February 2025
The latest count of the critically endangered Maaui dolphin is under way this week.
The Department of Conservation (DOC) Maaui dolphin abundance survey is carried out every five years along the North Island’s west coast.
The most recent survey in 2021 indicated there were 54 Maaui dolphins over the age of 1 living in the area.
The latest survey will be carried out over two summer seasons in 2025-26 and 2026-27 with field teams operating between the entrance of Kaipara Harbour in Auckland and the Mokau River in Taranaki.
Staff from DOC’s Taranaki, Auckland, and Waikato districts, the Marine Species Team, the University of Auckland, and Ngaati Te Ata will collaborate on the project.
Though long called Māui dolphins, the DOC press release said it had used the local Ngaati Te Ata dialect in the spelling of Maaui.
DNA samples will be collected from live, wild dolphins using a small biopsy dart, providing essential information about population size, genetic diversity, and movement patterns.
The new survey hopes to provide an updated estimate to track population changes and conservation efforts.
The survey is part of “vital work” to monitor and protect one of the world’s rarest marine mammals, DOC ranger Cara Hansen said in a press release.
“The Maaui dolphin is critically endangered, and every sighting or sample contributes to our understanding of the species and its future survival.”
The research to identify and monitor the dolphin uses a proven genetic mark-recapture method to estimate the population.
In much of Taranaki the use of set nets is banned within 13km (7 nautical miles) of shore, while in the north of region set nets are banned within 22km (12NM) of shore as part of a range of protections to prevent Maaui dolphin deaths.
Since 2012, commercial fishing boats operating in Taranaki waters have carried Ministry for Primary Industries observers to look for the Maaui dolphin. None have been seen.
Maaui dolphins are similar to Hector’s dolphins, which live off the coast of the South Island, but are physically and genetically different.
Both are most commonly observed seven nautical miles off the coast and are smaller than common dolphins.
They have a rounded black dorsal fin, similar in appearance to the ear shape of cartoon character Mickey Mouse, and their bodies have a unique grey, white and black colouring.
Maaui dolphins live till 20 years of age and breed slowly, starting at age seven and breeding only every two to four years.
Their habitats are impacted by water turbidity and presence of suitable prey.
As well as occasional deaths from human activity, Maaui dolphins are threatened by toxoplasmosis from animals.
Sightings can be reported through DOC’s hotline at 0800 DOC HOT (0800 362 468) or online Marine mammal sighting form: Conservation
“Real-time reports help our field teams understand where the dolphins are being seen and improve the success of our survey,” Hansen said.