Source: Department of Conservation
Date: 21 March 2025
Scientists have had favourable weather conditions and good success in locating dolphins, allowing them to gather valuable data that will help improve conservation efforts for this vulnerable species.
Hector’s dolphins (Cephalorhynchus hectori), also known as tutumairekurai, pahu, or upokohue, are endemic to Aotearoa New Zealand and are considered a taonga species. With an estimated population of 15,700, they are managed under the Hector’s and Māui Dolphin Threat Management Plan, which recognises four distinct sub-populations around the South Island.
“Until now, conservation management for Hector’s dolphins in Otago has been based on their assumed connection to other populations along the East Coast of the South Island. The local population is estimated at around 40 individuals,” says Anton van Helden, DOC Senior Science Advisor.
“By collecting high quality genetic samples, we can use these data to determine how closely related – or not – the dolphins in this area are to neighbouring populations, and ensure they are managed appropriately.”
“This research will provide a clearer picture of how Otago’s Hector’s dolphins are connected to other populations and will help guide conservation efforts. It builds on the valuable eDNA research already undertaken by the University of Otago,” says Anton.
Recent research by the University of Otago using environmental DNA (eDNA) provided an initial look at the genetics of these dolphins. The findings suggest they may be more genetically linked to dolphins on the south coast of the South Island rather than other east coast groups, raising important questions about population connectivity and exposure to regional threats such as fishing. However, while eDNA is useful for species detection, it does not provide the level of genetic detail needed to reliably assess population structure.
The survey team is using a well-established biopsy sampling technique, where a small, lightweight dart collects tiny skin and blubber samples from free-swimming dolphins. This method, which has been safely used on Māui dolphins for more than 15 years, provides high-quality DNA for genetic analysis with minimal disturbance to the animals.
“The tiny samples we collect are archived in the New Zealand Cetacean Tissue Archive (NZCeTA) and will give us opportunities to understand genetic relationships, age structure, aspects of their diet, and even reproductive status” says Anton.
The survey, which began on Sunday, 16 March, will continue until Saturday, 22 March, covering the coastline from just south of Oamaru to just north of Taieri. The collected samples will be analysed in collaboration with the New Zealand Cetacean Tissue Archive at the University of Auckland – Waipapa Taumata Rau and mana whenua.
With the survey progressing well, the data collected will contribute to the long-term protection of Hector’s dolphins, ensuring their survival for future generations.
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