DOC would like to remind park users of the importance of making sure they ‘Check, Clean, Dry’ when entering Fiordland National Park this summer to help prevent the spread of didymo and other freshwater pests.
Didymo is a freshwater alga and its microscopic cells can be spread by a single drop of water. The cells can survive on slightly moist gear for months and can be easily spread by human activities such as tramping, fishing, hunting, and watercraft use.
Annual testing of waterways throughout Fiordland conducted by DOC and Fish & Game have shown that the great majority of the park’s waterways remain didymo free, including high use rivers in the Milford Track Rivers Control Area. In 2013, a sample from the Large Burn tested positive for didymo, but this is the only site in Fiordland West of the Divide (except the Hollyford and Pyke River catchments) to do so.
The local focus for DOC Fiordland staff is on preventing the spread of didymo into the Clinton, Cleddau and Arthur Rivers in the Milford Track area, and keeping western Fiordland and Stewart Island didymo free. Many of these areas are still pristine and have intact ecosystems. Anyone heading into these areas should be aware of the risks, and make use of cleaning stations in Fiordland National Park.
Anglers are required to obtain a Clean Gear Certificate before departing for the western tributaries of the lakes.
Anyone heading upstream into the Iris Burn valley on the Kepler Track should take care not to spread didymo from the Upper Waiau and Lake Manapouri and the lower Iris Burn.
Department of Conservation ranger Chloe Corne said, “That so many waterways in Fiordland National Park remain free of didymo and other freshwater pests is a huge achievement which is only made possible by public support.”
Following the Check, Clean, Dry requirements also helps prevent the spread of other freshwater pests into the region, such as lagarosiphon (oxygen weed) and hornwort. Both of these plants can spread by broken fragments and, once established, can rapidly choke waterways and crowd out native aquatic plants.
Fish & Game compliance ranger Hamish Angus will be taking samples from 24 key waterways in Fiordland National Park this summer to test for didymo and DOC will run an annual survey to check for other freshwater pests near the end of summer. Compliance with regulations regarding clean fishing gear will be enforced.
- Didymo is a freshwater diatom/alga which smothers waterways, altering habitats for invertebrates, fish and aquatic plants
- It attaches itself to stream, river and lake beds and may form a thick brown layer that smothers rocks, submerged plants and other materials. Thick growths eventually separate into pale 'rats tails' that look similar to tissue paper.
- The cells are microscopic and can be spread by a single drop of water. Even if you can't see it you could be spreading it.
- The success of the Check, Clean, Dry campaign hinges on continued assistance from all recreational users; as long as people continue to take time to decontaminate their gear , we should all be able to continue to enjoy clear rivers and lakes.
- Fiordland National Park users should carry field cleaning kits (spray bottle, scrubbing brush, detergent, pack liner for use as a bucket – available at DOC Te Anau Visitor’s Centre).
- For Routeburn Track users, cleaning gear is available at The Divide for those heading into the Greenstone/Caples valleys.
- To help limit the spread of freshwater pests, Clean Gear certificates are required for some recreational activities in the park. For more information, contact the DOC Visitor’s Centre in Te Anau.
- See www.biosecurity.govt.nz/didymo for more information on Check, Clean and Dry.