Monitoring and Sampling Update
As of June 10, 2024, 26 water samples taken from high-priority areas in Clear Lake have tested negative for zebra mussel environmental DNA (eDNA). Currently, areas of focus are near Boat Cove and the area around the pier and the Clear Lake Marina. Water samples continue to be analyzed in Winnipeg by Fisheries and Oceans Canada on a priority basis. The likelihood of detecting zebra mussels increases as the water temperature warms.
On June 3, a Fisheries and Oceans Canada dive team completed visual surveys of the main pier, Clear Lake Marina, and the shoreline extending from the main pier to the Boat Cove.
So far, no zebra mussels have been found.
Containment Curtain Installation
Considering multiple positive tests for zebra mussel environmental DNA (eDNA) in Boat Cove throughout the summer of 2023, and the collection of live adult zebra mussels in the same area in November 2023, precautionary measures are being taken to contain and isolate the potential spread of zebra mussels in Clear Lake.
Within the next few weeks, containment curtains will be installed around Boat Cove and on the pier at Main Beach. These curtains are made of the same materials required for silt curtains (material that catches or stops sediment) used in many construction projects. The containment curtains installed in Clear Lake will increase the likelihood of zebra mussel detection by stopping lake currents and wind-generated flows.
If further evidence of zebra mussels (veligers, positive eDNA samples, living mussels) is found outside of the initial containment area, the curtains may be moved to that location.
Visitors can still enjoy swimming within the area contained by the curtains. The water within the contained area is the same as water outside the curtains. The curtains will likely be in place for the 2024 open water season.
Zebra Mussel Treatment
Parks Canada staff and partners are monitoring for the presence of an established colony of zebra mussels using multiple detection methods. If further evidence of zebra mussels is found in the containment area (veligers, positive eDNA samples, living mussels), and monitoring results from the remaining portion of the lake are negative, a treatment option using potash molluscicide may be considered. If no further evidence of zebra mussels is found, treatment may not be required.
If zebra mussels are detected, and a potash molluscicide treatment is feasible, it will be widely communicated.
If zebra mussels are detected, the containment curtains will be used to isolate the area. Then, if feasible, it will allow for the effective treatment of zebra mussels using potash molluscicide. Successful containment is essential for effective treatment while preserving the water quality and overall ecological integrity of Clear Lake.
Health Canada considers open-water potash applications at concentrations needed to kill zebra mussels safe for swimming.