There were a few anxious hours last summer after a sample was taken from Okanagan Lake and tested for being a possible invasive mussel infestation.
While the test ultimately revealed a negative result, over those few hours the question that arose for Okanagan Basin Water Board officials was, “If this is it, what now?”
James Littley, the deputy administrator for the Okanagan Basin Water Board, related that story during his presentation at the inaugural Okanagan-Interior Invasive Mussel Working Group meeting held Friday (March 8) in Kelowna at the Manteo Resort.
The forum had been months in the planning, an attempt by the water board to bring Okanagan Valley watershed business and government partners together to talk about prevention, limiting the spread and the impact of living with invasive mussels.
After the Okanagan Lake scare, the potential impact of invasive mussels showing up in a B.C. waterway took another concerning step with detection of the mussels in the Snake River in Idaho, 11 hours from the Okanagan Valley watershed and in a river that intersects with the Columbia River system just four hours from Osoyoos.
In Canada, the mussel infestations have advanced from the east coast to Manitoba, most notably in Lake Winnipeg.
How to keep the mussels out of B.C. and how to respond should the mussels show up in Okanagan Lake were top of mind for the more than 100 people who attended Friday’s forum.
There was a broad range of representation from across the Okanagan Thompson region including municipal and regional district governments, Indigenous leaders, environment consultants, and marina, boat operator and pile driving operators on Okanagan Lake.
Martina Beck, unit head of freshwater applied science and programs for the aquatic ecosystems branch of the Ministry of Water, Land and Resource Stewardship, also spoke at the forum, acknowledging the Snake River mussel detection response was a lesson in learning for B.C. moving forward.
Idaho opted to attempt a copper-based chemical treatment on a segment of the river, killing every living species.
There is no full-proof chemical treatment for mussels as of yet, so the long-term fallout from the Snake River treatment will be closely monitored. As well, the depth and expanse of Okanagan Lake will make any kind of widespread chemical treatment unworkable.
Beck outlined the province’s mussel defence program consists of a watercraft inspection, a water monitoring initiative, and public outreach and education.
“Coordinating with other groups across the board is also critical in forming working partnerships,” Beck said.
While the OBWB has called for stepped up inspection station monitoring resources and a two year moratorium on boats permitted from outside the province to access B.C. lakes, the province has so far not met those demands.
Beck said the watercraft inspection stations operate from April to October, with increased operations from June until late August.
She said in 2023, 20,900 boats were inspected, with 14 vessels identified as carrying mussels.
Of those 14 boats, 10 came from Ontario, one from Manitoba, and one each from Nevada, Michigan and South Carolina.
Eight of those boats were destined for the Okanagan Thompson region.
She added through a federal/provincial grant support program, 867 plankton tow samples were tested in 83 B.C. waterbodies, and all the samples came back negative.
Beck said the key lessons for B.C. from the Snake River response was being prepared to deal with logistical and chemical product access challenges, and the importance of working with partner groups to initiate a coordinated response to a positive sample mussel detection.
She said the Snake River detection occurred in late August, followed by a confirmation test, diver confirmation of mussel existence, a town hall forum for the community and the chemical treatment period between Oct. 3-13.
“It was a great opportunity to see the logistical challenge and components that go into this kind of response,” said Beck, who visited the test site during the chemical treatment process.
Beck said while the commitment is to keep the mussels out of B.C., developing a coordinated strategy on how to respond with local partners remains an important objective moving forward.
Littley reiterated the economic impact of mussels reaching Okanagan Lake are stark: $64 million to $129 million a year in annual mitigation costs; $8.1 million in boat and marina maintenance; $12.6 million in lost tourism revenue; and $30.2 million in lost property tax revenue.
And those figures, confirmed in a provincial study released last year, don’t account for ecosystem impacts such as loss of fish and municipal infrastructure maintenance requirements such as for water intake stations which are prime breeding ground for the mussels.
Littley said one positive is while Okanagan Lake is a high mussel contamination risk due to the calcium level of the lake water, Mission Creek doesn’t share that characteristic which is noteworthy because it is a significant salmon spawning ground and supplies 30 per cent of the annual fresh water intake to Okanagan Lake.
“That is good news for Kelowna but the reality is up and down the valley, the impact is otherwise high risk across the watershed,” he said.
Littley noted a single mussel can generate up to a million eggs, with adults able to survive in Okanagan Lake year-round and their prime breeding period being May to November.
“It takes eight weeks for a fertilized mussel egg to reach sexual maturity and reproduce. So a mussel introduced into a waterbody in May, its reproductive cycle will have a second generation by July, and a third generation by October,” he said.
“So by the fourth generation, we are talking literally millions of eggs from just a single mussel.”
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