Wartyback, snuffbox, round pigtoe, pocketbook … no, we haven’t gone crazy. These are just a few of the 41 wild and weird freshwater mussel species found in Ontario.
Hidden at the bottom of rivers and lakes and nestled under a layer of sand, these native molluscs often go unnoticed. But don’t let their odd names and rock-like appearances fool you. They play a significant role in keeping aquatic habitats healthy.
Todd Morris, a research scientist with Fisheries and Oceans Canada, explains that mussels perform many vital functions in aquatic ecosystems. A single mussel can filter approximately 40 litres of water each day, consuming large quantities of bacteria and algae, and leaving behind clearer, more habitable water for other aquatic species.
This ability to accumulate toxins makes them vulnerable to pollution and habitat changes. By monitoring mussels we can determine the state of our rivers and lakes. Healthy mussel populations are indicative of healthy watersheds!
In July, we joined Fisheries and Oceans Canada to conduct a mussel survey on Ontario Nature’s Sydenham River Nature Reserve.
“The Sydenham River is a special place for mussels,” says Morris, “the waterway running through Ontario Nature’s property contains as many as 32 species per square meter, many of which are species at risk, including the northern riffleshell, wartyback and snuffbox.”
Here’s something else that few people know: mussels are parasites. They must find a suitable host fish in order to reproduce and complete their life cycle, explains Morris.
Some mussels put on displays to lure hosts, mimicking small bait-like fish, while others release their larvae, or glochidia, into the water where the glochidia attach to a host fish as it swims by.
The snuffbox and northern riffleshell reproduce a little differently. Using their shell, they grab an appropriate fish by the head and release their glochidia onto it while it is trapped. This is called host capture. The glochidia develop within cysts on the fish’s gills and drop off when they become juvenile mussels.
The close connection between freshwater mussels and fish necessitates a holistic approach to mussel conservation. When we protect freshwater mussels, we are also protecting our native fish species and the quality of our Ontario’s waterways.
Next time you’re out exploring, try using Fisheries and Ocean’s Canada’s Clam Counter app to help identify and submit you mussel findings!
Cali Fox is a conservation intern at Ontario Nature with a B.A in environmental economics from McGill University. She is also a current candidate for the Masters of Forest Conservation program at the University of Toronto.