Mussel Heads
What happens on land affects life in the water.
A gang of ecologists descended on Barry County’s Podunk Creek.
Their mission?
To find some mussels!
While mussels may be some of the most overlooked animals among Michigan’s rich diversity of wildlife, they may have the most to say about water quality – and their lifestyles are like something from a sci-fi movie! Mussels are filter feeders, sustaining themselves on little food particles suspended in the water that they suck in through their slightly opened shells. In doing so, mussels clarify the water – but their bodies can also accumulate pollutants, including heavy metals. If the water is bad, this toxic build-up may eventually become too much for them to survive. And being the homebodies that they are, these creatures can’t move far – and are stuck with the water they’re in.
So, mussels get around streams and lakes by hitching rides on their very mobile neighbors, fish. Mussels shoot their microscopic babies (called glochidia) onto a passing fish, the glochidia latch onto the fish’s gills, then later fall off in a new spot. Some mussels can use many kinds of fish to get around, but others specialize on just one species – which makes them even more sensitive to change. And if the habitat loses the special fish species, it loses the mussels, too. This may be the reason why mussels are some of the most rapidly declining species in our region, and many are considered vulnerable to climate change.
Back at the creek, the gang of ecologists used elbow grease and a few ingenious tools to look for mussels, including buckets with plexi-glass bottoms that help clear glare and ripples that would otherwise make mussels difficult to see. They also checked the water’s quality by measuring pH and oxygen levels.
For their efforts, the crew found 5 of the 43 mussel species found in Michigan in this quaint little stream, critters with weird names like slippershell (Alasmidonta viridis), creek heelsplitter (Lasmigona compressa), ellipse (Venustaconcha ellipsiformis), spike (Elliptio dilatate), and round pigtoe (Pleurobema sintoxia). Two of these species are considered rare. Unfortunately, no live mussels were found – only their shells and fragments – which is often the case in these kinds of surveys. While the status of mussels in this stream remains a little unclear, the information gathered provides a great “baseline” for ecologists to compare to in future surveys.
The fascinating biology of mussels is a reminder that what happens on land affects life in the water, and that to protect these vulnerable animals that are part of Michigan’s natural heritage, we need to protect land and water quality on a landscape level.
The watery search took place at one of SWMLC’s newest preserves in Barry County, a place where the habitats are so sensitive that human impact must be restricted and public access is limited, and may only be gained with permission.
Thank you for your cooperation.
Story and photos — Mitch Lettow, Stewardship Director, Southwest Michigan Land Conservancy