Further research is to be done into the use of chelated copper as a possible emergency control of the invasive alga didymo.
Biosecurity Minister Jim Anderton said results from field trials of a chelated copper compound (Gemex) confirmed it had some potential.
"But more research needs to be
done about where and when it can be used and any possible effects it may have on non-target species such as molluscs, eels, koura [freshwater crayfish] and other algae."
He said chelated copper was not a "silver bullet" for removing didymo, and the best way to control its spread was for all users to check, clean and dry the equipment they used at waterways.
It made better sense to prevent didymo getting into waterways in the first place than trying to remove it once it was there.
MAF Biosecurity's didymo response manager Chris Bicknell said chelated copper was likely to be useful only in waterways with low levels of didymo and rivers below a certain size and flow.
Mr Anderton said $325,000 had been set aside for the research, which was expected to be completed by next June.
The research programme would include:
* Analysis of research to date to identify a list of criteria for assessing where chelated copper could be used to eliminate or control didymo.
* Laboratory trials to assess the impact of chelated copper on selected non-target species.
* Further monitoring of the Princhester Creek trial site for didymo and assessment of the longer term impacts of chelated copper on the river's ecology.
- NZPA
