Flexing their Mussels: Nature’s Bivalve Wonder

When the invasive species survey was being conducted in 2021 on Lake Windermere, it was observed that there were fewer freshwater mussels compared to other years. They usually show up on the rake tosses intended for plants, however their lack of presence sparked concern.

Unfortunately, freshwater mussels are amongst the most endangered organisms globally, with only six species known to occur in B.C. In North America, 45 percent of mussels have gone extinct or are endangered. As sudden changes to their environment continue to occur, such as man-made structures, dams, warming waters, changing precipitation, and pollution, it makes it difficult for the mussels to be able to adapt.

One might wonder what makes the native freshwater mussel so important? Mussels provide important ecosystem services; they are filter feeders, meaning they pump water into their shell, and eat tiny food particles (algae, bacteria, detritus), in large numbers acting like water filters! A single mussel can clean 50+ Liters of water per day! Because of this superpower, mussels are indicators of aquatic ecosystem health and can be used to track bioaccumulation. Another service they provide is to mix and oxygenate the lake bottom. Because of their burrowing capabilities, this process promotes increased productivity and diversity of life forms on the lake bottom.

Without freshwater mussels, our waters and ecosystems would be at great risk. If we recognize that everything living is connected, then we can understand that even something as small as a mussel can create significant ripple effects. The freshwater mussel is part of an ecosystem, and if any functional element fails, the entire system will be affected. Without the freshwater mussel, the water would no longer get filtered and the lake bottom will have less oxygen. The accumulation of elements and sediment would create an inhospitable environment for most fish, plants, and animals, including humans. Reduced light penetration would hinder photosynthesis, making the waters incapable of supporting diverse life. Without a healthy aquatic ecosystem, the lake would lose its appeal, and animals relying on it would suffer. Birds using Lake Windermere for breeding, migration, and habitat would also be affected, putting many species at risk as the ripple effects continue.

This is why protecting our mussels is so important. There are four species of freshwater mussels whose ranges include Columbia and Windermere lakes. They are: Western Pearlshell, Winged Floater, Western Floater, and Oregon Floater, however their presence and population are unknown. To gain a better understanding of the mussel population in our lake, Lake Windermere Ambassadors and Columbia Lake Stewardship Society are excited to be conducting a Native Mussels Survey. We will be seeking volunteers to assist with the survey every year in August so if you are interested in participating, please contact us at intern@lakeambassadors.ca.

Photo Credit: INaturalist.org