Restrictions on Okanagan milfoil control to protect mussels could hurt beaches

Efforts to protect an endangered species are impacting work to keep Okanagan beaches weed-free.

Invasive milfoil is regularly cleared from Okanagan lakes, especially in areas popular with visitors and locals.

However, increased efforts to protect the endangered Rocky Mountain Ridged Mussel on the lake bottom means some beachgoers could encounter a lot more weeds.

According to the Okanagan Basin Water Board, that’s because the province has dramatically increased the areas of lakes where the water board is not allowed to rototill this winter to clear milfoil in an effort to protect the mussels.

“The primary beach that we are concerned about right now …is Kin Beach in Vernon. Five years ago, when the mussel was first starting to be regulated, they made us stop rototilling at about half of Kin Beach,” said James Littley, the water board’s operations and grants manager.

“Now, it has extended to the whole length of the beach so this winter it has received no rototilling.”

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If the water board continues to be restricted from rototilling at Kin Beach and in other areas of Okanagan lakes, it expects the milfoil growth in those areas will become thick over the years.

“It will be quite a nuisance. People tend to panic when they get into the weeds. It also encourages water fowl to come, Canada geese in particular, and so it can decrease water quality. It just won’t be a pleasant experience,” Littley said.

Tweet This Click to share quote on Twitter: "It will be quite a nuisance. People tend to panic when they get into the weeds. It also encourages water fowl to come, Canada geese in particular, and so it can decrease water quality. It just won't be a pleasant experience," Littley said.

The water board is questioning whether the mussels can even thrive in a thicket of milfoil.

“The province and the federal government, as far as I know, don’t have any research suggesting mussels can even survive in a thick milfoil bed,” Littley said.

“Other mussels can’t survive in low-oxygen environments, and one of the effects of thick milfoil beds is to create low-oxygen environments at the bottom of the lake.”

New provincial guidelines for local rototilling are expected in the coming weeks.

However, the board is concerned restricted areas will only increase over time as more mussels are found.

Littley expects the board will be allowed to continue its summer milfoil-harvesting program but notes that this is less effective at clearing the milfoil.

Littley’s discussions with the province suggest the board may be able to continue rototilling the milfoil in restricted areas at deeper depths. However, he expects that would also leave beaches with a thick milfoil band at the prime swimming depth.

The provincial ministry responsible has yet to respond to questions about the future of rototilling in Okanagan Lake but said in a statement the practice would continue to be allowed in Vaseux Lake, a much smaller lake in the south Okanagan.

Fisheries and Oceans Canada has yet to respond to a request for comment.