Zebra MusselInvasive Species IdentificationZebra mussels (Dreissena polymorpha) are small, freshwater mussel with a triangular shape, usually 2 – 5cm long. They often have yellowish and brown zigzag banding but colours can vary a lot.Zebra mussels attach to hard surfaces by sticky threads. They have a flat underside such that when you put them onto a flat surface they lie steady, rather than rolling around.Rarely seen alone, zebra mussels often occur in huge numbers.ThreatAfter one year, a female zebra mussel can produce up to 1 million eggs. The larvae are free swimming for several weeks, and then settle on any hard surface under water.When they are present in large numbers zebra mussels filter the water so effectively that there is little food left for native aquatic animals.Zebra mussels settle in such large numbers that they can clog intake pipes and completely cover underwater objects, including boat hulls and our native mussel species.ActionInspect and clean all equipment like boats, waders, engines etc. with high pressure hot water and/or an appropriate disinfectant before and after use in lakes and waterways. Unclean equipment can result in the spread of invasive species into different catchment areas.Proper control of a zebra mussel infestation will require the services of an appropriately certified invasive species control company. If you encounter zebra mussels please enter the details into our log.