Didymo Stakeholder Update - 26 June 2008
26 June 2008
The purpose of this update is to keep you informed about the work underway in support of the didymo long-term management partnership.
Responsibility for didymo programme management
From 1 July the didymo long-term management (LTM) programme and associated activities will formally become the responsibility of MAF Biosecurity New Zealand's Pest Management Group. Corinna Bennett is the new Didymo LTM Coordinator.
Didymo research completed
MAFBNZ has now completed its didymo research programme.
Gemex™ Impact on Non-Target Species
Gemex™ concentrations were assessed for the short term effects of Gemex™ on a range of non-target species. The toxicity data showed that sensitivity to Gemex™ increased as exposure times and Gemex™ concentration increased, with amphipods being the most sensitive of the species tested, followed by trout and bullies.
Water hardness also had a significant influence on copper toxicity to non-target species with survival being greatest at higher water hardness levels. Predictions were that even in soft water there would be minimal impact on dwarf galaxias, koura and snails. It remains unknown whether increased water hardness will decrease the toxicity of Gemex™ to didymo.
There was no significant bioaccumulation of copper in adult koura exposed to high concentrations of Gemex™ for up to 8 hours, suggesting that risks to humans and other predators consuming koura after a Gemex™ treatment of a waterway is likely to be minimal.
Long time effects of Gemex™
An assessment of long term (10-11 months post -treatment) effects of Gemex™ was undertaken at the site of the small river trial of early 2007. The review found that there was no evidence of long-term adverse effects of a single dose of Gemex™ on the non-target species tested. Although trout were affected in the short-term, trout densities had returned to near pre-treatment levels 11 months afterwards. Copper concentrations in the water and fish were also within acceptable drinking water, human health and protection of ecosystems guidelines by this time.
Multiple doses of Gemex™ should be more effective than a single dose but may also elevate impacts on non-target species. This needs to be taken in to account when considering the use of Gemex™ to control didymo in a river or stream.
Didymo-Gemex™ decision support tool
A decision support system has been developed to assist regions wishing to assess the feasibility of the use of Gemex™ in specific waterways.
Didymo knowledge sharing tools in place
The didymo knowledge sharing project is now complete. The project has delivered three tools.
The quick guide
This hard copy folder provides summaries of key information for the long-term management of didymo and guidance on how to find the complete set of information.
The electronic library
This web-based tool, didymo.net, contains the authoritative knowledge that is available to be shared amongst didymo long-term management partners to assist them in making management decisions about didymo.
The shared workspace
This is an internet based forum for discussion and informal sharing of information among didymo long-term management partners.
The internet sites are not publicly accessible. Password access is available to those partners who are directly involved in the management of didymo. Applications for access should be made to Corinna Bennett, Didymo Long-Term Management Programme Coordinator, corinna.bennett@maf.govt.nz
Communications update
The MAFBNZ communications team attended the Hutchwilco Boat Show in Hamilton last month. This was very successful, with the Check, Clean, Dry message very well received. Next month we will be attending the Christchurch Boat show. We think this is an important event to attend as it is mainly attracts trailer boat owners.
The ACNeilson didymo summer campaign evaluation is due for completion at the end of July. Partners will receive an outline of the results. The results will give us an indication of areas that are working well, and areas that need more attention. This information will be valuable when planning your upcoming summer programmes.
The didymo social marketing material will again be available this financial year. We are planning on refreshing some of the items such as the brochure; however the messages will stay the same.
Process for reporting suspected didymo finds
The following flow chart illustrates the process for when a member of the public has a suspected didymo find. It is important that if a member of the public reports a suspect find to your organisation, either they or your organisation rings the 0800 number to ensure this information is getting to the correct person.
