Source: Earth Sciences New Zealand
Scientists have used drones to video green turtles feeding in New Zealand waters for the first time.
Rangaunu Harbour in Northland was surveyed last summer to assess the feasibility of aerial drones for monitoring green turtles.
Earth Sciences New Zealand fisheries scientist Dr Brit Finucci says they found a potential of 18 unique individuals from 27 sightings.
“We saw them actively foraging in shallow seagrass habitats during high tides. This is something locals have reported seeing but wasn’t yet officially documented, meaning we now have video proof that the harbour is a foraging ground for green turtles in New Zealand,” said Dr Finucci.
Green turtles are the only sea turtle species to reside year-round in New Zealand waters, with juveniles using shallow coastal habitats as foraging grounds before dispersing throughout the Pacific.
We don’t know where they go when they leave New Zealand waters.
The survey, “Trialling a honu monitoring tool for iwi-led honu reporting in Te Hiku”, was a collaboration between Ngāi Takato, Ngāti Kahu, Moana Whenua Trust Limited, Department of Conservation, Conservation International, and Auckland Museum.
Dr Finucci says they also confirmed the feasibility of using drones as a monitoring tool for turtles and other marine megafauna.
“This method could help communities collect and display turtle data, as well as that of other marine life known to occur in the harbour. Human impacts on estuaries and coastal New Zealand ecosystems, including Rangaunu Harbour, mean we need to identify and protect critical green turtle habitat as soon as possible,” she said.
Department of Conservation Principal Ranger Paul Mills says the discovery of green turtles feeding in Rangaunu Harbour is both exciting and significant.
“I believe this mahi should continue, with biodiversity monitoring and public education both playing key roles. Turtles are a high-profile species that really capture public attention, and they can serve as powerful ambassadors for the health of coastal ecosystems – from seagrass beds to fish stocks – all of which are facing growing pressure from human activity and climate change,” Mr Mills said.
Hapū Cultural and Environmental Monitor, Nina Raharuhi of Haititaimarangai Marae had a message to boaties and recreational fishers in the harbour.
“Kia tupato, ata haere… Be cautious and take it easy in the harbour as these beautiful species reside here amongst us!”
While surveying, the team documented other diverse marine fauna, including eagle rays, stingrays, and several fish species.
Re:wild Shark Conservation Director, Mark Erdmann says he was surprised at how readily they found the turtles by drone.
“We use drones extensively in our surveys of oceanic manta rays in the coastal waters of Aotearoa, but I wasn’t sure how well drones would work on green turtles – potentially camouflaged against the seagrass beds they were feeding on.
“I was surprised at how readily we found them, not only when they were on the surface breathing, but even when submerged and feeding in the seagrass. There’s tremendous potential to expand the scope of this drone monitoring of honu across northern New Zealand,” said Mr Erdmann.
