Summary
Cover of the publication showing
Undaria pinnatifida
The first established New Zealand populations of Undaria, a large brown kelp native to Asia, were recorded in Wellington in 1987. The species spread steadily around New Zealand's coast and was discovered in Big Glory Bay, Stewart Island on March 13 1997.
Delimitation surveys the following month around Stewart Island and the South east coast of the South Island, including Bluff Harbour, suggested Undaria was restricted to a localised area of marine farms in Big Glory Bay. Attempts to eradicate this founding population were initiated by the Department of Conservation in late April, on the advice of recognised national algal and pest management experts. The aim was to prevent establishment, and further spread around Stewart Island, and into Fiordland and the Subantarctic Islands.
The eradication programme in Big Glory Bay consisted of the manual removal of any Undaria plants located during regular dive inspections of marine farm structures and shoreline areas neighbouring known populations. Monthly or bimonthly diver surveys were timed to detect and remove all sporophytes before they reached sexual maturity and release spores. Mussel rafts, barges, ropes and boats harbouring Undaria were also treated or removed from the water to kill the microscopic gametophyte life stage.
A surveillance programme was implemented at high-risk invasion sites at Bluff Harbour and around Stewart Island to detect spread or new Undaria incursions. The eradication programme was extended to Bluff Harbour (1999), and Halfmoon Bay (2000) following the discovery of new founding populations.
The programme successfully controlled the original founding population of Undaria to low densities, and prevented spread from Big Glory Bay. However, eradication was not achieved, primarily due to two new incursions arising from independent founding events at Bluff Harbour and in Halfmoon Bay, Stewart Island. Ongoing costs of control at all three sites could not be sustained without central government funding and development and adoption of a national Undaria management program. Central government support was withdrawn in 2004 when the Southland Conservancy was unable to convince the funding agency (Biosecurity New Zealand) that the ongoing eradication/control programme was justified particularly when prioritised against other biosecurity projects. The programme therefore ceased on November 30, 2004.
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Publication information
Louise Hunt1, Lindsay Chadderton2, Mike Stuart3, Sean Cooper4, Morven
Carruthers5
Published by
Department of Conservation
PO Box 743
Invercargill 9840
New Zealand
© Copyright New Zealand Department of Conservation 2009
ISBN: 978-0-478-14582-3 (web PDF)
1 MAF Biosecurity New Zealand, PO Box 2526, Wellington. Lou.Hunt@maf.govt.nz
2 The Nature Conservancy Great Lakes Program, Department of Biological Sciences, University of
Notre Dame, PO Box 369, Notre Dame, IN 46556, USA. lchadderton@tnc.org
3 Golder Associates (NZ) Ltd., PO Box 1087, Dunedin 9054. mstuart@golder.co.nz
4 Department of Conservation, PO Box 10-420, Wellington. scooper@doc.govt.nz
5 Department of Conservation, PO Box 743, Invercargill. mcarruthers@doc.govt.nz