Secretary Island operational plan: Part A stoat eradication

Published:  

June 2007
The objective of this document is to outline an operational plan for the removal of stoats from Secretary Island and its continued maintenance in a stoat-free state.

Background

The proposal to make Secretary Island stoat free was first put forward in 2001 (Munn, 2001). Since 2001 there have been several expeditions to the island to assess the potential for stoat eradication.

Secretary Island is the second largest (8140ha) and highest island on the Fiordland coast, rising to an elevation of 1196m above sea level. The island supports a diverse range of plant communities and habitats. 

It is relatively isolated which has restricted the number of mammalian pest species that have invaded its shores. Only capable swimmers such as stoats (Mustela erminea) and red deer (Cervus elaphus scoticus) have managed to reach the island.

There are no accurate records for when stoats arrived on Secretary Island. Stoats were first recorded on Resolution Island (35km south of Secretary Island) in 1900 (Hill & Hill, 1987) and it is likely that stoats also arrived on Secretary Island about this time.

The impact of stoats on native wildlife has been well documented throughout New Zealand (see King, 2005). For an island such as Secretary, which has no rodents, the effects stoats have on wildlife are thought to be much greater than in areas with both stoats and rodents.

The removal of stoats from Secretary Island will give protection to many species on the island that are vulnerable to predation such as Fiordland crested penguin (Eudyptes pachyrhynchus), titi (Puffinus griseus), Northern Tokoeka (Apteryx australis), weka (Gallirallus australis), karearea (Falcon novaeseelandiae), kakariki (Cyanoramphus auriceps) and Fiordland skinks (Oligosomo acrinasum). 

Conservation Objectives
To enhance the existing ecological values of Secretary Island by eradicating stoats and to minimise the risk of reinvasion by reducing stoat density on the adjacent mainland and stepping stone islands. To reintroduce threatened species (e.g. mohua, tieke – saddleback, South Is. robin) to Secretary Island once it is stoat-free.

Operational Objective
To establish a network of marked trap lines, flyable bivvies, and VHF communications over Secretary Island for the purpose of removing all stoats from the island.

Planning is also underway to remove and/or control to zero population density red deer.

Publication information

ISBN 978-0-478-14228-0 (hardback)
ISBN 978-0-478-14229-7(PDF)

Prepared by Chris Golding, Pete McMurtrie, Kerri-Anne Edge and Murray Willans

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