ASFB Home > 2003 > Biological Invasions: Consequences for Parasites, Pathogens, Emerging Diseases, and Fisheries in the Marine Environment.

Incursion response to Undaria pinnatifida in southern New Zealand

Chadderton, W.L.,¹ Stuart M.,² Cooper, S.,³ West, C.J.,³ Harrison, A.⁴

¹Department of Conservation, P.O. Box 112 Hamilton
²36 Tidewater Drive, RD2 Dunedin.
³Department of Conservation, P.O. Box 743 Invercargill
⁴Department of Conservation, P.O.Box 10 420 Wellington
Email: lchadderton@doc.govt.nz

Undaria pinnatifida, a laminarian kelp native to coasts of Japan, Korea and parts of China, has become widespread along the central and eastern coastlines of New Zealand since its discovery in Wellington Harbour in 1987. In March 1997, U. pinnatifida was discovered on mussel farms at Big Glory Bay, Stewart Island, well outside its known range. An incursion response was initiated by the Department of Conservation based upon independent technical advice and peer review. An eradication programme was established to prevent the spread of U. pinnatifida around Stewart Island, Fiordland and the Sub-Antarctic Islands. These ecosystems are recognised nationally and internationally for the intact nature, diversity and/or unique features of their marine communities. Monthly manual removal of plants (sporophyte stage), coupled with the removal or sterilisation of infested farm equipment and harvest of infested mussel farms, has succeeded in reducing U. pinnatifida to near zero populations in Big Glory Bay. Subsequent invasions of nearby Bluff Harbour and Halfmoon Bay from northern populations were detected and contained by manual removal and treatment of infected substrate with heated water. Monitoring of coastal shipping in southern ports identified potential vectors requiring treatment. Surveillance monitoring also identified an Undaria infected vessel that grounded and later sank in the shallow coastal waters of the Chatham Islands. Treatment of the hull was initiated once it was clear the vessel could not be refloated and towed away from the shore. The long term viability of the incursion response is uncertain, but it has demonstrated what can be achieved with a targeted, rapid response to a marine invasive species. Lessons learnt and the development of tools should contribute to refined marine biosecurity responses.

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