Species At Risk


(Epioblasma triquetra)


Snuffbox occurrences map


The Snuffbox is a small freshwater mussel, less than seven centimetres in length, which can be distinguished from other species by its thick, smooth, and triangular-shaped shell. The shell is often yellow-green with darker green rays that resemble dripping paint.


In Canada, the Snuffbox is now only found in the East Sydenham River and the Ausable River in southwest Ontario. The total population size is very small. Historically, the species was also found in Lake Erie, Lake St. Clair, and the Thames, Detroit, Grand, and Niagara rivers.


The Snuffbox is typically found in small to medium-sized rivers in shallow riffle areas. They prefer clean, clear, swift-flowing water and firm rocky, gravel or sand river bottoms. Mussel larvae are parasitic and must attach to a fish host, where they consume nutrients from the fish body until they transform into juvenile mussels and drop off. In Ontario, the main fish host for Snuffbox is the Logperch but other host fish may include various darter species, Largemouth Bass, Mottled Sculpin and Brook Stickleback. Like all freshwater mussels, the Snuffbox feeds on algae and bacteria that it filters out of the water.


The greatest threats to the Snuffbox are invasive species and pollution from agriculture and siltation, which occurs when too much soil washes into the river from nearby agricultural and urban areas. The Zebra Mussel, an invasive species from Europe, is a serious threat because it attaches to native mussels and can kill them by interfering with breathing, feeding, excretion and movement. Conditions that threaten the fish host species can also threaten the Snuffbox.


The Snuffbox is protected under Ontario’s Endangered Species Act and the federal Species at Risk Act.

What You Can Do to Help the Snuffbox

  • The Ministry of Natural Resources tracks species at risk such as the Snuffbox. You can use a handy online form to report your sightings to the Natural Heritage Information Centre. Photographs with specific locations or mapping coordinates are always helpful. nhic.mnr.gov.on.ca
  • Report any illegal activity related to plants and wildlife to 1-877-TIPS-MNR (847-7667).
  • You can help improve mussel habitat and keep Ontario’s water safe and clean by maintaining natural vegetation next to creeks and rivers. The roots of plants reduce erosion and can stop soil from washing into the river. Fence off streamside areas to keep cattle (and their manure) out of the water. There are many other things that you can do to help reduce soil erosion and you might be eligible for funding assistance. For more information, visit the Ontario Soil and Crop Improvement Association: www.ontariosoilcrop.org.
  • Private land owners have a very important role to play in species at risk recovery. If you find Snuffbox in a watercourse on or adjacent to your property, you may be eligible for stewardship programs that support the protection and recovery of species at risk and their habitats.
  • Invasive species seriously threaten many of Ontario’s species at risk. To learn what you can do to help reduce the threat of invasive species, visit: ontario.ca/invasivespecies; www.invadingspecies.com; www.ontarioinvasiveplants.ca; and, www.invasivespecies.gc.ca.
  • Volunteer with your local nature club or provincial park to participate in surveys or stewardship work focused on species at risk.

Did you know?

The Snuffbox’s main host is the Logperch, which is known to frequently roll over small stones and gravel in search of food. The Snuffbox waits patiently for a Logperch to come along and touch its shell. The Snuffbox then captures the Logperch in its shell and holds the stunned fish long enough to puff out a cloud of mussel larvae that attach to the fish gills, where they live as parasites that consume nutrients from the fish body. The startled fish is then released.

Did you know?

Mussels rely on a lot of good luck in order to reproduce. Males release sperm into the water, and if there happens to be a female nearby, she will capture the sperm as she filters water in search of food.

Did you know?

Aboriginal people harvested mussels for food and to create jewelry and tools. In the 1800s, massive numbers of mussels were harvested from the Grand River to create buttons. Millions were shipped out every year until the 1940s when plastic buttons became more popular.

The Endangered Species Act

Contact your local ministry office

Often the best source of local information on species at risk is your nearest ministry office. Call with your questions or concerns.