20/10/2026
Did you know that most Orca visits to Whangārei harbour occur at this time of year – during Spring? On the other hand, dolphins gather predominantly during Winter.
Orca visit more frequently than some might imagine. Data from a specialist acoustic detection system and tracker installed by Northport on a moored buoy in Marsden Bay, near the Whangārei Harbour entrance, show that Orca visited Whangārei harbour 38 times over 23 days between September 2024 and September 2026.
The technology from New Zealand acoustics firm Cetaware reports in real time the presence of marine mammals visiting the harbour. Following a successful trial it has replaced acoustic devices where recorded information had to be retrieved manually every few months.
The system is a ‘passive’ listening device. It detects the sounds that whales and dolphins make without using any form of sonar or underwater signal. It identifies the species of animal and sends that information, instantaneously, to any internet-enabled device.
It’s highly accurate (99%) and has an impressive confirmed detection range of more than 2.5km for dolphins and 2.7km for Orca in our busy environment, with consistently high levels of vessel traffic and buoy movement.
This technology has changed our marine mammal monitoring capability. Because the information is supplied in real time we can manage potential operational interactions with marine mammals.
Now that we have completed the trial of the Cetaware system we intend to make the readings it collects accessible on our website. We’ll post about this once it’s available.
