Rogue rat sparks biosecurity response

Date:  01 September 2017

Conservation dogs Gadget and Wai with handler Jane Tansell, arriving on Resolution Island to search for rats
Image: Sandra King

Greg Lind, DOC Operations Manager (Te Anau) said a male ship rat was discovered by DOC Rangers on a routine trap-check of the island in late July.

"The rat had been caught in a trap at the north-east of the island, at a mooring site near Disappointment Cove," Greg said.

"Its location strongly indicates the rat had arrived from a boat which had moored at this point.""We ask all boat operators to be vigilant for unwanted stowaways. Ensure fresh rat bait is in place at all times and check vessels for signs of rodents, such as droppings and gnawing."

The largest island in Fiordland, and the fifth largest in New Zealand, Resolution Island (21,000ha) is a strategic site for conservation. The island has no rat or possum populations, and stoats are maintained to very low numbers due to an extensive trapping programme involving almost 3000 traps.

This has allowed a range of threatened native species to flourish, including Southern Fiordland tokoeka (kiwi), rock wren, kea, kākā, fernbirds, Fiordland skink and mohua. The island also has the potential to be a major breeding site for many of New Zealand's most vulnerable species.

Lindsay Wilson, DOC Principal Ranger (Biodiversity) said a biosecurity incursion response was immediately launched on Resolution Island, and an additional intensive trapping network set up in the area the rat was discovered.

"Rodent detector dogs were also deployed across the north-east section of the island. No further rats have been caught or detected, however, this incursion has once more raised the issue of biosecurity on Fiordland's remote islands," Lindsay Wilson said.

Many of Fiordland's islands are either predator free, or have predators held to very low densities. These islands are sanctuaries for New Zealand's most vulnerable species, such as kākāpō and tieke/saddleback.

Greg Lind said it would be devastating if predators were to gain a foothold on these precious island sanctuaries.
"The impact on the resident native species would be disastrous."

If you are visiting pest-free islands, make sure you complete any biosecurity requirements to prevent unwanted pests coming with you. Report any sighting of predators on predator-free islands to the DOC conservation emergency hotline 0800 DOC HOT (0800 362 468).

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