Didymo Stakeholder Update - January 2007

DATE 19 January 2007

Summer Communications Programme

The summer programme is now fully in place.

Over 80% of all our communications material has been distributed and repeat orders are now coming in. What has already been distributed includes:

• 65,000 spray bottles
• 100,000 information packs
• 10,000 packs of branded jelly beans and sun screen
• 700 signs have gone out to the regional councils

At the Inter-Island ferry terminals up to 2000 cars a day have been approached and given the didymo message. Our message is also being broadcast over the weather track screens, at information centers, on the ferries and at both ferry terminals, and the didymo coloring-in competition is underway and open to all ferry passengers.

There has been great support from all the partners, related industry and the public for the programme. On behalf of the Response team we would like to thank you all for your support in making the summer programme a success and reducing the spread of didymo.

Takaka River find

Unfortunately didymo was found in the Takaka River on 28 December 2006. Biosecurity New Zealand, Fish & Game, DoC, and the Tasman District Council are working collaboratively to provide a coordinated response to the detection of didymo in this new region.

Biosecurity New Zealand has commissioned a detailed localised delimiting survey centered around the Takaka River that will determine the extent of any spread. In addition to this, DoC is currently surveying several rivers in the Nelson/Marlborough area as part of their scheduled didymo surveillance programme to determine which rivers in the region are infected. Results from these two surveys, as well as Biosecurity New Zealand's January 2007 national delimiting survey will provide a comprehensive picture of the situation in the upper South Island.

The recent ERMA approval for the use of a chelated copper product in a special emergency now allows Biosecurity New Zealand the option to consider the possible treatment of a didymo detection. For a number of reasons, specific to the Takaka River, Biosecurity New Zealand has asked NIWA to do a feasibility study on attempting elimination through use of the chelated copper control tool. The feasibility study will assist Biosecurity New Zealand in making the decision to proceed or not with the possible use of the chemical control tool. The feasibility study should be completed by mid-February.

The Takaka River is the 28^th river known to be affected by didymo. All of these rivers are in the South Island.

Spring-fed creek research

Biosecurity New Zealand has commissioned our Long Term Management Partner, Fish and Game, to investigate the effect of spring-fed creeks on the survival of didymo. Observations made by Fish and Game Southland field staff indicate that didymo is not present in the lower reaches of two spring-fed creeks that are tributaries of a didymo-infected river. Observations suggest the community structure and water chemistry in spring-fed streams differ to that of the main river channel. Results from this research will assist Biosecurity New Zealand in assessing and developing possible long term management tools.

Detections over the Christmas period

Over the holiday period there were five positive didymo finds in new sites in the South Island. These are:

• Ettrick Burn River mouth, Lake TeAnau
• Lochie River mouth, Lake Wakatipu
• Pelorus River at Daltons Bridge
• Speargrass Stream in the Upper Buller Catchment

A number of samples were collected from the North Island over this period, and all have been negative to date.

The Biosecurity New Zealand website map will be updated by the middle of next week to show all new finds.

Ongoing didymo surveys

Three different didymo surveys are currently progressing.

• Takaka localised delimiting survey: Biosecurity New Zealand is commissioning NIWA to undertake a localised delimiting survey in response to the Takaka River didymo detection. The purpose is to determine the outer boundary of the incursion centered around the Takaka River, primarily because of the detection’s proximity to Te Waikoropupu Springs, a recognised high value site.
• DOC Nelson/Marlborough survey: This survey was planned by DoC prior to the Takaka detection. The purpose is to determine the presence or absence of didymo in a wide range of rivers in the Nelson/Marlborough region.
• January 2007 National Delimiting Survey: Biosecurity New Zealand scheduled for late January a New Zealand-wide survey of ~140 high risk sites, part of its national delimiting survey programme and the second of three surveys planned for the 2006-07 summer. The survey is commissioned to NIWA. Site selection has been modified to avoid duplication with the other two surveys mentioned above.

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