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Media Release |
18 February 2005
Algae Management Options Under Review
Biosecurity New Zealand (BNZ) in conjunction with Environment Southland is holding three information meetings this week to explain the latest developments with the algae incursion of Didymosphenia affecting some 200 km of the Waiau and Mararoa Rivers, Biosecurity New Zealand Senior Adviser Christina Vieglais, said today.
“Efforts to date have been focused on ensuring the algae are not spread to other water systems. It appears this alga has not been eradicated anywhere else in the world, so our interim options are limited to containment. Meanwhile, we are investigating the feasibility of controlling or eradicating the algae.
“Scientists had expected to find the algae in other nearby rivers, but microscopic examination of 550 samples from four adjacent rivers has not detected it. This supports the importance of containment while we assess our long-term management options.
“We have been heartened by the high level of awareness of the problem and the level of responsibility river users have shown to minimise the spread of the algae. People have been keen to do as much as they can to protect this river system and BNZ would like to thank them for their cooperation and support,” Dr Vieglais said.
BNZ in conjunction with Environment Southland will hold a series of public meetings this week to keep river users and interested parties informed about containment measures and future management options.
The meeting details are as follows:
Date: 22 February 2005 Venue: Environment Southland, cnr North Rd and Price St, Invercargill Time: 7.30pm
Date: 23 February 2005 Venue: Te Anau Club, Cnr Pop Andrew Dr and Jackson St, Te Anau Time: Noon
Date: 23 February 2005 Venue: Waiau Town and Country, King St, Tuatapere Time: 8pm
Key Facts
- It is not known how long Didymosphenia has been present in the Waiau and Mararoa, but available evidence suggests it may have been present and unobserved for at least 5 years before this season’s extensive bloom.
- Didymosphenia is found in cool temperate northern hemisphere river systems. It is not known how it came to be established in Southland.
- BNZ has declared Didymosphenia to be an Unwanted Organism under the Biosecurity Act 1993. It is an offence to spread an Unwanted Organism with penalties of up to five years imprisonment, and/or a fine of up to $100,000.
- Little information exists internationally about containment, control or eradication measures for Didymosphenia. There has never been an attempt to perform a large scale eradication such as would be required in Southland.
- BNZ, DOC and Environment Southland have put in place measures to minimise the spread beyond the Waiau and Mararoa river systems. River users have been advised to avoid using these river systems, especially if they intend to use other freshwaters soon thereafter.
- Any person that does use the waters of the lower Waiau, the Waiau Arm or
the Mararoa must ensure any item that has been in contact with those waters
has been thoroughly cleaned before use in other freshwaters, using the
following approved methods:
1. Users must remove all obvious clumps of algae from items before leaving the river
2. Users must soak and scrub all items for one minute in a 2% solution of household bleach (200 mls in a ten litre bucket of water) OR a 5% solution of salt, nappy cleaner, antiseptic hand cleaner or dishwashing detergent, OR completely dry all items for at least two days before using in other waterways. - The Ministry of Health considers Didymosphenia to be a nuisance species and not a significant human health risk. Water taste and odour have been known to be affected. Swimmers may experience scratchy, red, watery eyes after swimming.
For further information: See hot topics at http://www.biosecurity.govt.nz Contact Biosecurity New Zealand Communications Adviser, Tina Nixon: Ph 0272232789
