(PR.co.nz) Didymo has been found in three more Nelson-Tasman rivers this year but there have been no new finds of the pest algae in Marlborough and Kaikoura waterways.
Samples were taken from more than 40 waterways for didymo testing over recent months in the annual survey to determine the spread of didymo in the top of the South Island. The survey discovered didymo in the Riwaka and Pearse rivers and it was confirmed to be in the Maruia River from a sample collected by a member of the public.
Lindsay Vaughan of the Tasman District Council, who leads the Top of the South regional didymo management group, said, “Most river users Check, Clean, Dry their gear to stop the spread of didymo and other aquatic pests, although it can be inconvenient.
“Obviously, some river users have not been doing this. Protecting our remaining pest-free high quality waterways depends on everyone taking time to Check, Clean, Dry if they are moving between waterways.”
Department of Conservation Nelson/Marlborough Technical Support Manager Martin Heine said the department was particularly appealing for people to avoid spreading didymo into habitat for the endangered native whio/blue duck.
“Didymo is in several waterways that are important for whio, including the Fyfe and Baton rivers, Sandstone Creek, and now the Pearse River. Trampers, anglers and others using or crossing waterways are urged to Check, Clean, Dry boots and other gear before putting them in other waterways or upstream. We want didymo kept out of the parts of these and other Kahurangi National Park waterways that whio live on, including the Wangapeka River.
“The long term effect of didymo on invertebrates on which whio feed isn’t yet known but didymo can form dense mats which may affect invertebrate populations and reduce the food source for whio.
“National parks contain some of our most pristine waterways that are important freshwater habitat for native species. The public is asked to help limit the spread of didymo in these precious environments.”
Footnote
* The survey covered waterways considered to be a higher risk of being infected with didymo or with high ecological values. Testing took place in some rivers already known to have didymo to determine its spread in those waterways.
* 21 Nelson-Tasman waterways are now known to have didymo.
* In Marlborough and Kaikoura, two rivers have been found to have didymo – the Wairau and the Clarence.
Media Release 6 May 2010 from Department of Conservation.
Contact: Lindsay Vaughan, Tasman District Council, Telephone (03) 543 8400