‘Rock snot’battle lines drawn
21 January 2008
The call to action to protect against rock snot (didymo) has taken on new urgency with it being detected in two more
major South Island rivers.
Regional Group Co-ordinator for the Northland/Auckland Didymo/Freshwater pests Partners Group, Mark Geaney, is worried
about the latest finds and is calling on the public to get vigilant and fight didymo.
“We know didymo is spread by human activity,’ he says. “We are particularly keen to get our message out to people who
use freshwater areas for their recreation. Kayakers, trampers, boaties and anglers can all unwittingly spread didymo and
we urge them to check clean and dry their gear every time.”
“The best way to protect against didymo is to ensure that absolutely anything that has been in contact with freshwater
is decontaminated before it hits the next waterway. Check gear and remove debris, clean gear with a mild solution of
detergent or household bleach and dry it thoroughly when moving between waterways” says Mark.
“If you can’t decontaminate your gear between waterways then you should dry to the touch and leave for an additional 48
hours before using in another waterway, or restrict use to a single waterway.”
Microscopic live didymo cells hitchhike on gear like tramping boots, waders, fishing lures, kayaks and tyres then jump
off in new freshwater sites. We can‘t see the cells, but they are there - and they can live in or on damp gear for
weeks.
Didymo is an invasive freshwater alga that forms ugly, dense, fibrous mats in the water up to 12 cm thick. It can choke
waterways and affect habitat and food sources for other species. It also gives waterways a dirty, polluted look. As yet,
we have no effective way of getting rid of it.
“It is very bad news for the environment, the economy, and people who love to spend their leisure time in our pristine
rivers and lakes. We need our Check Clean Dry message to go out loud and clear to Kiwis and visitors to New Zealand
alike.
Didymo was first detected in New Zealand in 2004 in the Lower Waiau River in Southland. Since then it’s spread at a
terrific speed, taking over many rivers in the South Island and threatening to travel north.
“It’s time for those of us who love getting out and enjoying our fresh waterways to get serious about slowing the spread
of didymo in the South Island - and let’s make darned sure that we keep it out of the North Island. It really is in our
hands to stop the spread of this pest,” says Mark.
The Northland/Auckland partners group was formed in July 2007 and is made up of representatives from the Auckland
Regional Council, Northland Regional Council, Department of Conservation, New Zealand Federation of Freshwater Anglers,
Ministry of Fisheries, Fish and Game, Watercare Services Ltd, iwi, and other special interest groups.
Funding is provided by MAF Biosecurity New Zealand as part of their ongoing work to manage the spread of didymo.
Full cleaning instructions can be found on www.biosecurity.govt.nz and you can report any possible sightings of didymo
to 0800 80 99 66.
ENDS