Egeria is an invasive freshwater weed that grows rapidly, is long-lived, and can outcompete native freshwater species. Large clumps of Egeria can come free from the underwater meadows where they grow, causing flooding by blocking waterways and drainage. It can also choke hydro turbines. It forms large underwater meadows that shade out smaller native species, and prevents seedlings of native species establishing. Its rotting vegetation stops the flow of water, killing fauna and flora. Egeria has the potential to cause negative effects on environmental and recreational values in Otago.  

As only male plants are found in New Zealand, no seed is set. New plants form from stem fragments that break off, and through human activities on boats, trailers and equipment.  

Egeria is found throughout the North Island, with only a few sites in the South Island. It has not been reported in Otago. 

To prevent the establishment of Egeria in Otago and its negative effects on economic well-being and environmental values, Egeria is in the exclusion programme of the Otago Regional Pest Management Plan (2019-2029). 

Egeria is declared an Unwanted Organism in the National Pest Plant Accord (NPPA). Any species declared a pest under the NPPA cannot be sold or be in a place where plants are being sold. Pest plants cannot be propagated, bred, multiplied, communicated, released, caused to be released, or otherwise spread.      

Otago Regional Council will be responsible for controlling the plant if it gets into Otago, most likely in collaboration with the Ministry for Primary Industries, Department of Conservation, Land Information New Zealand, and land occupiers. If you think you have spotted Egeria, please let us know by calling 0800 474 082 or emailing biosecurity@orc.govt.nz 

Preventing the spread of Egeria using the Check Clean Dry method is the best strategy, as removal of invasive freshwater pests is both difficult and expensive. 

Cleaning your craft and gear for biosecurity purposes is an important way to help protect the freshwater environment. Just as regular maintenance keeps your equipment in good condition, biosecurity cleaning keeps lakes and rivers healthy for everyone. 

To make sure you are not spreading any aquatic pests, the Check Clean Dry method is the best way to keep our waterways pest-free.