Abel Tasman offshore islands declared 'predator free'

Tuesday, 26 March 2019

Motuareronui Adele Island in the Abel Tasman National Park is back to being a native paradise after all pests were eradicated from the island.

The islands off the coast of the Abel Tasman National Park have been declared free of predators once again.

But conservation staff have warned there is a risk of rats and mice reaching the islands through visiting vessels.

Department of Conservation operations manager Chris Golding said following a pest control operation in 2017, monitoring has shown there are no longer mice on Adele/Motuareronui, Fisherman/Motuareroiti and Tonga islands.

He said it was possible rats and mice could reach the islands by hitching a ride on visiting vessels or by swimming across from the mainland.

'People planning to go to the islands should check before going out on the water that boats, kayaks, all bags, containers, food and gear are clear of mice, rats, ants, spiders or other animals.

'All clothing, footwear and gear should be free of soil and plant material, including seeds and foliage.'

An Abel Tasman Birdsong Trust trap in the Abel Tasman National Park.

Public access is not allowed on Tonga Island, except by permit, to protect the island's New Zealand fur seal breeding colony.

'We want people to enjoy the nature experience on the two islands that can be visited, Adele and Fisherman, but we need all visitors to make sure they don't have stowaway pests on board that could escape onto the islands.'

Rats and stoats can swim the around 800 metres distance from the park mainland to the islands. Mice are not thought to be able to swim more than 500 metres but it's possible they may have swum from the Abel Tasman mainland to the islands.

DOC first carried out an operation to eradicate mice from the islands in 2007.

A rat and a stoat were found dead in traps on Adele, the rat in February 2012 and the stoat in January 2013. Then after heavy beech seed fall, a rat and 13 mice were caught on Adele Island in 2015.

There are biosecurity measures in place on the islands to help protect them from invading predators, including traps to catch them and tracking tunnels that record footprints to detect them.

DOC staff have reviewed and strengthened these measures to detect predators earlier so they can be quickly eradicated before their numbers build.

There is now a stoat trapping network across nearly 95 per cent of the national park, maintained by DOC, Project Janszoon and the Abel Tasman Birdsong Trust to help prevent predators swimming across to the islands.