Addressing invasive caulerpa in New Zealand: Modelling the benefits of alternative mitigation options using the natural capital valuation approach

Iwi of the Pou Rāhui Project (Ngāti Paoa, Ngāti Hei, Ngāi Tai Ki Tāmaki, Ngāti Tamaterā), in collaboration with three regional councils, formed a strategic partnership to develop an indicative business case aimed at combating the invasive seaweed Caulerpa, which is rapidly spreading across the coastal waters of the upper North Island.

MartinJenkins was engaged as the lead advisor to develop this business case and sought specific advice from NZIER to undertake economic modelling to support the assessment of options to fight invasive Caulerpa. This modelling considered the economic impact of these options on the current and potential future impacted areas in New Zealand. In particular, NZIER was asked to build on the approach and methodology developed in our previous Valuing the Hauraki Gulf report and estimate the benefits of a range of alternative mitigation options relative to a ‘do minimum’ that assumes Controlled Area Notices (CANs) continue to be the main form of intervention.
A technical reference group comprising representatives from iwi, regional councils and Biosecurity New Zealand provided critical review and input on the modelling parameters, assumptions and initial results.

Led by Ting Huang and Roshen Kulwant, with advice and oversight from Michael Bealing, Peter Clough and Deputy Chief Executive (Auckland) Christina Leung, NZIER analysis was adopted into the wider business case and delivered in December and is currently under review by the Government.