Satellite tags track turtle journeys of nearly 3,000 kilometres

A satellite tracking study is showing how green sea turtles move around New Zealand waters, with one turtle travelling between Rangaunu Harbour and Wellington and back.

Since 2025, 11 rehabilitated honu/turtles fitted with satellite tags have been tracked daily for 6 to 12 months. Dr Karen Middlemiss, DOC Marine Senior Science Advisor and project lead, says the work is part of the most comprehensive sea turtle tracking study in New Zealand waters.

Juvenile and sub-adult green sea turtles do not breed here, but they are regularly seen in warmer North Island waters. Little has been known about whether individual turtles stay for long periods or move between places.

“We are sort of like a baby-sitting service for teenagers before they leave New Zealand and return to their nesting beaches in the wider Pacific region,” said Middlemiss.

What the tracking found

The tags give highly accurate location data, helped by the new Kinéis constellation of 25 satellites. The research has identified several turtle hotspots to focus future work on.

In Northland, the hotspots are Rangaunu Bay and Harbour, Pārengarenga Harbour, Murimotu, Whangārei Harbour and the Bay of Islands. In Auckland, the hotspot is Manukau Harbour.

One turtle, nicknamed 3K, clocked up nearly 3,000 kilometres over four months. It travelled the west coast between Rangaunu Harbour and Wellington and back, with a month-long pitstop in Manukau Harbour on the way home.

Another turtle, released at Taupō Bay in Northland, travelled the east coast to the Coromandel. It then returned north and settled in Rangaunu Harbour. Turtles that spent most of their time in that harbour were most often located over seagrass and harbour channel areas.

Support from iwi and the zoo

Nina Raharuhi, Hapū Cultural Monitor for Ngāti Kahu with Ngāti Whātua affiliation, urges locals to support turtle conservation.

“As tangata whenua, we support every effort that honours the mauri of our moana and ensures our honu can thrive within their natural habitat,” said Raharuhi.

Auckland Zoo Veterinary Services Manager Dr James Chatterton says August to December is the peak season for unwell turtles. Eight have been admitted to the zoo since June.

According to the zoo, the illnesses include trauma from fishhooks, line entanglement and boat strike. Turtles also get pneumonia and intestinal infections.

“The good news is more than two-thirds of the green sea turtles we admit go on to make a full recovery,” said Chatterton.

What happens next

Team Turtle is a collaboration between DOC, Auckland Zoo and iwi. It is continuing its partnership with iwi and hapū and aims to tag more turtles, bringing the total monitored to 20.

Middlemiss says the next step is to turn the information into conservation action. DOC is keen to talk with regional councils about getting turtles recognised in relevant coastal management plans.

DOC also lists ways boaties can reduce collisions with sea turtles: slow down in known turtle habitat and keep the boat off the plane, wear polarised sunglasses to spot turtles under the surface, nominate a spotter to alert the skipper, and fit a propellor guard.