Mussels threaten milfoil work
A tiny inhabitant of Okanagan Lake could bring weed control at a popular beach to a grinding halt.
The Okanagan Basin Water Board has been told by the Ministry of Environment that it can’t rototill Eurasian milfoil weed at part of Kin Beach because it could disrupt the habitat for the rocky mountain ridge mussel, which is indigenous to the lake.
“There is a conflict between what we’re trying to do with an invasive species (milfoil) and mussels,” said director Juliette Cunningham.
According to the Committee on the Status of Endangered Wildlife in Canada, the rocky mountain ridge mussel is considered a species of special concern.
“Population sizes in British Columbia have not been determined; however, they are believed to be declining,” states a COSEWIC report.
Eurasian milfoil is not indigenous to the valley and was first discovered in the Vernon arm of Okanagan Lake in 1970.
Cunningham says there is a need to control milfoil in areas visited by tourists as well as ensuring it doesn’t disrupt water intakes.
The provincial government ended funding for weed control years ago and it is now completely funded by local communities.
“It’s frustrating because we’ve taken this on,” said Cunningham of provincial rules preventing rototilling.
It’s not clear if there is a compromise that meets the needs of OBWB and the ministry.
“They have indicated that if we want to rototill, we have to move the mussels, but they’re not sure how many there are to move and if they are moved, if they would survive,” said director Doug Dirk.
“Milfoil is an invasive species but they say they have no mandate with it. There needs to be a lot of clarification.”
Beyond the conflict between rocky mountain ridge mussel and milfoil, OBWB is looking towards a potentially more significant issue.
There are concerns that zebra and quagga mussels will eventually show up in local lakes after spreading across North America since the 1980s. Both are native to eastern Europe.
“It’s shocking how easily this infestation could impact our waters,” said Cunningham.
“One mussel will have one million larvae.”
These non-native mussels clog water intake pipes, pumps and boat motors. They also deplete food sources for fish and produce toxins that kill fish and birds and contaminate drinking water.
“They thrive in high calcium water, which is Kalamalka Lake,” said Dirk.