Common name:  Egeria
Scientific name:  Felis catus
Management programme:  Egeria densa


Why are they a pest?

Large clumps of egeria can come free from the underwater meadows where they grow, causing flooding by blocking waterways and drainage and it can choke hydro turbines. It also 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.

What does it look like?

Egeria is a slim aquatic plant with floating stems and linear, dark green leaves that are in spirals of 4-6. From November to January it produces white flowers that are 3-petalled with yellow stamens (the male fertilising organ of a flower), that sit on the surface of the water. As only male plants are found in New Zealand, no seed is set, however new plants form from stem fragments that break off. It grows in mostly still or slow-moving, highly lit underwater sites, like Otago’s beautiful lakes, and survives in a wide range of temperatures.

What are the rules?

While there are no rules for landowners in Otago regarding egeria, if it gets into Otago, ORC would take the lead role in control. Over the life of the pest plan (10 years), the goal is to stop egeria establishing in Otago to prevent negative effects on economic well-being and environmental values.

How will we achieve that?

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. Please let us know if you think you have spotted egeria by calling us on 0800 474 082 or emailing

How can I control it?

If you think you have egeria, please let us know by calling us on 0800 474 082 or emailing and we will take care of controlling it.

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.

Management programme