Due to the presence of endangered Rocky Mountain Ridged Mussels, rototilling milfoil is limited in some parts of Osoyoos Lake this year. (File photo)

By Vanessa Broadbent

Osoyoos Times

The Town of Osoyoos is joining the battle against restricted invasive weed control on Osoyoos Lake.

At their open meeting on Monday afternoon, council voted to join the Okanagan Basin Water Board (OBWB) in asking the provincial government to lift a ban on removing Eurasian watermilfoil from several spots in some Okanagan lakes, including Osoyoos Lake.

Every winter, the OBWB rototills milfoil on its lakes, but cannot do so in some areas, including Haynes Point, this year because of concerns that pulling out the weed  disturbs the habitat of Rocky Mountain ridged mussels, native to the Okanagan and classified as at-risk under the Species at Risk Act.

In a letter asking for local governments’ support in contacting federal and provincial governments, OBWB executive director Anna Warwick Sears said that rototilling removes the density of the weed by 80 to 97 per cent in one treatment, and is the reason most local beaches are free of invasive weeds.

• Read more: Endangered mussels limit milfoil removal

While the Okanagan basin is the only location the mussels are known to exist in Canada, it only makes up five per cent of their total population, Warwick Sears said.

“Milfoil rototilling is now prohibited in any areas where Rocky Mountain ridged mussels are found based on an assumption that this weed control method could cause harm.”

Letting the milfoil grow could instead create poor water quality and habitat for the mussels and other species, Warwick Sears said, along with cause social and economic harm.

Mayor Sue McKortoff chairs the OBWB and said the limitation to milfoil harvesting is a detriment to local lakes.

“I can’t emphasize enough how important this issue is,” she said.

The OBWB’s letter to the ministers of Fisheries and Oceans Canada and Forests, Lands, Natural Resource Operations and Rural Development outlines concern for a lack of information.

“While we strongly support the protection of native species and their natural habitats, we believe that a more evidence-based and balanced approach is needed in this particular case,” Warwick Sears writes.

In the letter, the OBWB requests that its milfoil control program be formally authorized on a permanent basis.

The OBWB is asking other local governments to send letters as well.