Didymo Stakeholder Update - May 2007

DATE 29 May 2007

Regional meetings for didymo long-term management

During April and May Biosecurity New Zealand staff coordinated and led a series of meetings around the country. Eleven meetings were held with regional partners including regional councils, Department of Conservation, Fish and Game New Zealand, Ministry of Fisheries, iwi and affected industry. The purpose of the meetings was to discuss how to implement the didymo long-term management programme at regional level.

As a result of the meetings, eleven regional groups have been formed, broadly based on regional council boundaries and covering the whole of both islands. With leadership and support from Biosecurity New Zealand group members will share knowledge and resources for the prevention, detection and management of didymo in their regions, and will work together to ensure the summer social marketing campaign, and particularly the 'check, clean, dry' message, reaches as many people as possible. Biosecurity New Zealand will lead the campaign and develop supporting material.

The focus on long-term management of didymo reflects the reality that national eradication is considered unlikely at present, but keeping didymo out of the North Island remains a key objective for Biosecurity New Zealand and the regional groups.

2007/08 financial year didymo cabinet paper – on-going programme

Cabinet will shortly be considering advice developed by officials on the future of the didymo programme. The advice to Cabinet reflects the programme that MAF has developed with partners at a national and regional level. Partners in the development have included the Department of Conservation, local government, Fish and Game New Zealand, specific Maori entities and affected industry.

Delimiting survey

The May delimiting survey is almost complete. The final few samples will be analysed early this week and the affected waterways map will be updated. Eight confirmed positives have resulted from the survey to date. These include: Young River, Cardrona, Dart, Tasman, Kakanui, Maerewhenua, and Matakitaki.

Didymo is currently known to be in 52 rivers and five lakes in the South Island, covering nine catchments.

Simulation to test plan for a North Island didymo detection

We will be running a North Island didymo detection simulation Thursday May 31. The purpose of the exercise is to test and refine existing response plans, to clarify the roles and responsibilities of various organisations in the event of a North Island find, and to raise awareness in the North Island of the threat of didymo.

Didymo science programme update – Takaka feasibility study

As we reported in an earlier update, a significant new detection of didymo was discovered in the Takaka River, Nelson, in late December 2006. The results of an assessment into the feasibility of eliminating didymo locally using the experimental chelated copper control tool still under development are now available on the Biosecurity New Zealand website (www.biosecurity.govt.nz/pest-and-disease-response/pests-and-diseases-watchlist/didymosphenia-geminata/science-technical#takak).

Consideration was given to the logistics of using the chelated copper treatment, the likelihood of success, the impacts on the river ecology and river users, and the possible effects on groundwater and Te Waikoropupu Springs.

Treatment of the Takaka River was not recommended, as the probability of successfully eliminating didymo with one treatment of chelated copper was low and there was insufficient data available to develop a dosing strategy that would have a high probability of success in a system as large as the Takaka River. In addition, treatment of the lower Takaka River was likely to exceed Ministry of Health safe drinking water levels in the aquifer below Takaka township.

Further detail is required regarding the accumulation and potential impacts of the chelated copper formulation on the aquatic environment over short and long-term time frames.

To report an exotic pest or disease, call the MAF Emergency Pest and Disease Hotline: 0800 80 99 66.