Aquatic Invasive Species Banner

Lake Manitoba Zebra Mussel Detection


In late July 2021 zebra mussel veligers (larval stage) were detected in water samples collected from Lake Manitoba Narrows. These samples were taken as part of the Aquatic Invasive Species (AIS) Unit’s annual surveillance monitoring.

Veligers were found in all nine samples taken from this area of the lake in quantities ranging from two to 12 veligers per sample. This indicates there could be an establishing or reproducing population in the lake.

It didn’t have to be this way

To prevent the spread of aquatic invasive species, such as zebra mussels, water users using watercraft and water-related equipment in a water body in Manitoba must follow the general AIS requirements.

As well, if watercraft and water-related equipment were last used in:

  • an Aquatic Invasive Species Control Zone
  • an invaded water body e.g., Lake Manitoba, Assean Lake
  • a tributary to the first impassible barrier or connected water body of a control zone or an invaded water body,

the items must be also decontaminated prior to placing them into another water body.


Restricted access signage (as shown) is placed at access points of invaded water bodies that are not yet designated as AIS Control Zones. This includes water bodies such as Lake Manitoba. The signs are to notify surface water users of this decontamination requirement.

Prevention is our best defense

It is essential that all water-users take the necessary steps to prevent the spread of aquatic invasive species.

Provincial watercraft inspection stations can assist surface water-users with inspections and decontaminations. Operating hours and locations of the watercraft inspection stations can be found here.

The open-water season and the winter (ice-covered) season checklists are helpful resources that can help you comply with the AIS requirements. In addition to these requirements, set fines for AIS offences are in-effect year-round.




Other Notices




Resources