Recent tests for didymo in 19 rivers in Fiordland National Park have all come back negative, a result that has pleased staff at Fish & Game and the Department of Conservation (DOC).
Didymo is known to be well established at a number of sites around Southland and the eastern boundary of Fiordland National Park, including Lakes Te Anau and Manapouri and the Eglinton and Waiau Rivers.
Each year Fish & Game and DOC collect water samples from previously uncontaminated rivers and send them to NIWA for analysis. This monitoring work enables DOC and Fish & Game to assess the effectiveness of existing approaches for controlling the spread of didymo and to make changes, such as installing additional cleaning stations, as required.
DOC biodiversity ranger Sanjay Thakur said the fact that this is the second year running with no new records of didymo spread is very good news and shows that the “Check, Clean, Dry” campaign has been highly effective at stopping the spread of didymo in Fiordland.
“Unfortunately, once didymo is established in a waterway there is no known way to get rid of it, so the best we can do is try to keep didymo out of unaffected rivers and lakes. These results confirm that this is an achievable goal, and as long as anglers, trampers, hunters and other users continue to check, clean and dry their gear, Fiordland’s waterways should remain pristine for many years to come.”
Most of the rivers selected for monitoring are either popular with anglers or associated with tramping tracks, such as the Clinton and Arthur Rivers along the Milford Track, and receive large numbers of recreational users over the summer season. Mr Thakur believes that the results showing these rivers are all still didymo free is entirely thanks to people’s willingness to take a moment to check, clean and dry their gear. Concessionaires, such as Real Journeys and Ultimate Hikes, who bring large numbers of visitors into contact with Fiordland’s precious waterways, also deserve much of the credit for ensuring that their clients all clean their boots before setting out.
“The success of the ‘Check, Clean, Dry’ campaign clearly shows that the greatest threat to Fiordland’s rivers is complacency: As long as all recreational users continue to take a minute to decontaminate their gear, we should all be able to continue to enjoy beautiful clear rivers”, Mr Thakur said.
More information about didymo is available at the Fiordland National Park Visitor Centre. Simple, lightweight didymo cleaning kits are available to purchase, and a cleaning station is available for public use free of charge upon request.