Blue-Green algae's are widespread in many lakes and rivers in New Zealand, and are found in a wide range of water quality conditions, including relatively 'clean' waters.
Under favourable conditions, blue-green algae cells can multiply and form blooms in lakes or thick mats attached to river and stream beds. Some species produce natural toxins called cyanotoxins which are a potential threat to people and animals if present in drinking water or if people and animals come into contact with the water during recreational activities.
Favourable conditions for these algaes is based on the right combination of warm temperatures, sunlight, low or stable river flows, and nutrients. The occurrence of mats or algal blooms is a natural phenomenon but human activities, such as agricultural nutrients entering waterways, can make things worse.
Toxic algae species include: Cyanobacterial micorocystis spp, Anabaena spp, Kirchneriella spp. Many of New Zealand's fresh waterbodies are suffering from these algae's such as seen in the Wairarapa & Hutt Rivers.
If your waterway has algal issues, the best thing to do is be proactive as costs greatly increase when the system becomes choked. For more information or if you would like a free onsite consultation you can call us on 0800 NZ WATERWAYS (0800 699 283) or fill out our contact form on the 'CONTACT' page with your postal address.
NZWR utilizes a relatively large planktivorous species of fish known as Silver Amur for the eradication of aquatic algae. Although Silver Amur are an introduced species from China they are classified as a restricted fish, not a pest fish. As they cannot breed in NZ waterways, do not bottom feed like Koi Carp and eat phytoplankton they pose no real risk!
Silver Amur provide a simple, cost effective, long term solution (generally living for around 20 years) for combating algae's. With effective management of Silver Amur stocking rates, algae can be removed from water bodies in a timeframe that is suitable to the objectives and budget of your release.