95bFM New research indicates pest control measures are affecting tuatara
8 May, 2025
Interview by Castor Chacko, adapted by Vivek Panchal
A new research paper published in the New Zealand Veterinary Journal has found potential risks with Brodificum, a rodenticide or rat poison, available over the counter on tuatara.
This follows research on four dead tuatara kept in captivity with Brodificum in their system.
Brodificum is used on islands with a tuatara population to protect the species from being eaten by rats.
Professor in the School of Biological Sciences at the University of Auckland, James Russell, told 95bFM’s The Wire that the likely reason for finding Brodificum in the tuatara’s system is due to what they have been eating.
“Some insects had probably eaten the poison and then snuck into the tuatara's enclosure and those tuatara had been gradually snacking on them and building up a lethal dose.”
As a result, he says it is important to consider when and where these poisons are used, where there is a huge population of tuatara.
Russell says we should look at using less potent rodenticides, like difenacoum and bromadiolone, which have a lower chance of bioaccumulation in the ecosystem.
“We're looking at a better and more strategic use of the toxins we already have, and that's what the Department of Conservation already does through limiting the use of Brutificum on the conservation estate, but also developing some new toxins,” he says.
He added that the University of Auckland is working with a larger team to develop a new pesticide called Norbormide which specifically targets rats.
Russell says more investment in developing new toxins to protect our native animals is needed.
“We have over 100 species of endemic birds in New Zealand. New Zealand is also a biodiversity hotspot for reptiles with over 100 species of endemic skinks and geckos, and the most cherished ones being this ancient lineage that goes back 200 million years.”
“We really do want to look after them, and we've done a great job of that through eradicating rats from islands, allowing the tuatara populations to recover and flourish.”
