Endangered mussel prevents milfoil removal in certain parts of Okanagan Lake

Milfoil is parts of Okanagan Lake could prove to be a bit of a nuisance for swimmers and boaters this summer.

The expanded discovery of the Rocky Mountain Ridged Mussel in certain sections of the lake has thrown the Okanagan Basin Water Board a curveball in recent months.

Because of the mussel, which is native to the area but was declared an endangered species in 2010, the OBWB has had to cut back on its milfoil management this winter.

“They wanted us to take precautions regarding our milfoil control program so that we weren't disturbing these mussels,” said Corinne Jackson, OBWB communications director.

“It was based on a study that wasn't very thorough and a more recent study found that we actually have maybe more of these mussels than we thought we did.”

While the OBWB waits to learn more about this mussel and the restrictions it imposes on them, it’s made their duty of tackling milfoil, an invasive weed, more difficult.

Typically, rototilling is performed in the winter to dig up and kill milfoil in the lake, but James Littley, OBWB operations manager, says they’ve had to stay away from certain areas.

“We have been able to conduct rototilling in most of our regular areas,” he told NowMedia, “but there are some significant areas where we’ve been excluded from doing any rototilling this year.”

Those areas include the Vernon arm of the lake, the Casa Loma area of West Kelowna and around Summerland, while parts of Skaha Lake and Osoyoos Lake haven’t been rototilled either.

One positive is that the mussels haven’t been found along the Kelowna foreshore, so it’s been business as usual in one of the lake’s most popular beach areas.

However, a single report of a Rocky Mountain Ridged Mussel in the area would impose a big risk on the OBWB’s milfoil removal program.

“Everywhere they find an individual mussel, there's 100 metres on either side of that individual that we'll no longer be able to treat,” said Littley.

Littley says they’re still waiting to find out on new regulations and what it means for their program, but hopes the fact that they’re tackling an invasive weed gets them a little latitude.

For now, the OWBW’s hands are pretty tied and the areas that haven’t been rototilled this winter will likely stay that way for the time being.

Although the milfoil isn’t a health risk, it does pose a bit of a hazard for boats and swimmers.

It can get wrapped around boat props and clog them and swimmers can get tangled in it as well, which can cause panic and a difficult situation for some that aren’t as strong in the water.

Milfoil can also negatively affect water quality for a number of reasons, which can lead to toxic algae blooms and swimmer’s itch.