Parks Canada is considering its next step after eight living juvenile zebra mussels were found in Clear Lake last week.
Staff will investigate options for an eradication treatment at the Riding Mountain National Park site.
A ban on all watercraft, including motor boats, canoes and paddle boards, remains in place. Parks Canada took the measure in May to try to protect the lake, curb the spread of the invasive species and study the issue.
TIM SMITH / BRANDON SUN FILES
A containment curtain, seen here, was set up along a portion of Clear Lake in Riding Mountain National Park. The curtain got dislodged soon after it was erected and has since been removed.
Parks Canada announced Sept. 9 that an underwater curtain to contain the mussels would be removed after it was dislodged by wind and waves shortly after it was installed weeks earlier. It was hoped it would contain the mussels to one section of the lake after Parks Canada reported a live adult mussel and a partial shell were found July 17.
In the first discovery in November 2023, a clump of 48 live zebra mussels was found in the area. There were warning signs the species was present in the summer of 2022. A water sample taken as part of Parks Canada’s aquatic invasive species program tested positive for environmental DNA.
In the summer of 2023, the federal parks agency increased testing on the lake and required boaters to undergo an inspection and tagging program before putting watercraft into the lake.
Cottagers and business operators in the area are concerned about the effect on the environment and tourism.
Zebra mussels reproduce quickly and starve other aquatic life of natural resources, such as algae. The mussels interfere with water intake and boating equipment and the sharp shells are dangerous for swimmers.
The invasive species was first detected in Manitoba — in Lake Winnipeg — in 2013.
— Staff