Sampling of selected waterways around the Te Anau Basin, and wider Fiordland will soon begin, coinciding with the open season for sports fishing in Southland’s rivers on 1 November

Date:  05 November 2012

Sampling of selected waterways around the Te Anau Basin, and wider Fiordland will soon begin, coinciding with the open season for sports fishing in Southland's rivers on 1 November. Graeme Peek, the Te Anau Basin Compliance Ranger for Fish and Game Southland, will be sampling 22 waterways within Fiordland to assess whether they test positive for the invasive freshwater pest didymo, also known as 'rock snot'.

Didymo was first discovered in Southland in 2004 in the Waiau and Mararoa Rivers, although there are reports that it had been established in the Mararoa River since 2001. Since this time, the pest plant has spread to at least 46 waterways in the region, as well as to a number of waterways in other parts of the South Island. When blooming, didymo can form thick mats which smother waterways and exclude the growth of native plants. This in turn can impact on the entire ecosystem of a waterway.

Fish and Game Southland have once again been contracted to undertake water sampling for the Department of Conservation, whilst undertaking their routine compliance work throughout the summer. They will also be maintaining the cleaning stations, which are located at lakeside huts around Lakes Manapouri and Te Anau. These are provided for park users to clean their gear before venturing into potentially unaffected tributaries, with the aim to prevent the further spread of didymo.

If using Southland waterways you are urged to 'Check, Clean and Dry' between each catchment. This involves checking gear that has come into contact with freshwater for any obvious clumps or signs of algae, then washing the contaminated gear with a 5% solution of dishwashing liquid to water for at least one minute. Alternatively, didymo can be killed during the drying process. Gear must be dry to the touch, then dried for a further 48 hours to ensure all spores are completely dead. Whilst these measures are effective at killing didymo, they will also help prevent the spread of all aquatic weeds which pose a risk to Southland's waterways.

To fish almost anywhere within Fiordland National Park, anglers need a 'clean gear certificate' from an approved cleaning station (listed below), as well as their current sports fishing licence. To obtain a certificate, evidence of clean gear is required, as well as a cleaning kit to take on trips to nominated waterways. This means anglers will have to wash their gear at one of the approved cleaning stations, or show that it has been dry for longer then 48 hours.

All anglers wishing to fish in Fiordland are reminded to check for specific conditions relating to different areas of the park. Read more about Fiordland National Park or contact Fiordland National Park Visitor Centre, phone +64 3 249 7924.

Didymo is an unwanted organism under the Biosecurity Act 1993. It is an offence to knowingly spread an unwanted organism with penalties of up to 5 years imprisonment, and/or a fine of up to $100,000. Additionally, anyone caught fishing within the control areas without a clean gear certificate may face prosecution and a fine of up to $5,000. Whilst summer is a great time to get out and enjoy the waterways around Southland and Fiordland, it is important that users keep both their own safety and the health of the waterway in mind.

Approved cleaning stations

  • Fiordland National Park Visitor Centre in Te Anau
  • Borland Lodge
  • Manapouri Motors
  • Outside Sports Te Anau
  • Fish & Game in Te Anau and Invercargill
  • B&B Sports in Gore


Lyndsay Murray
DOC biodiversity ranger Lyndsay Murray
Phone: +64 3 249 0200

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