Didymo - Where is it?
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Didymo has been detected in a number of freshwaters in the South Island. It has not been detected in the North Island, but that is no guarantee that rivers there are unaffected - didymo is microscopic, so the risk of spread will not always be obvious.
This map shows sampling sites and waterways where didymo has been found.
Didymo Samples Database
The didymo samples database is an internet based system that provides a single source registry to record all didymo sampling results taken throughout New Zealand. The database includes both negative and positive results, and sample locations that are displayed on a map.
Access to the database is password protected. Please email didymo@maf.govt.nz to enquire about obtaining a username and password.
Read only access is available using the username Didymo and password didymosamples1.
Delimiting Surveys
Didymo was first identified in the Lower Waiau River, Southland in October 2004. It was found during a routine Meridian Energy survey of alga growth by NIWA and Southland Fish and Game staff.
MAFBNZ has conducted a number of didymo delimiting surveys. Each survey included selected sites throughout New Zealand being sampled for the presence of didymo. For more information please see the links below with the results and reports from previous surveys.
2006-07 Summer National Delimiting Surveys
(3092 Kb)
August 2006 Delimiting Survey
(1597 Kb)
May 2006 Delimiting Survey
(1053 Kb)
January 2006 Delimiting Survey
(756 Kb)
October 2005 Delimiting Survey
(2076 Kb)
Likely environments map of the South Island
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Detailed Map
(16170 Kb) (note large file size)
Static Map
(73 Kb)
Likely environments map of North Island
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Detailed Map
(14443 Kb) (note large file size)
Static Map
(76 Kb)
Contact Us
Didymo Enquiries
MAF Biosecurity New Zealand
PO Box 2526
Wellington
NEW ZEALAND
Phone: 0800 809 966
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