Species At Risk

Mapleleaf Mussel

(Quadrula quadrula)


Mapleleaf Mussel


The Mapleleaf Mussel is a medium- to large-sized freshwater mussel that grows 12 centimetres long. Shell colour varies from yellow-green to brown. It somewhat resembles a maple tree leaf due to its square-ish shape and two raised ridges of nodules along the shell that form a “V” outline and resemble the veins in a tree leaf. It also has growth lines (dark bands) that look similar to the rings in a tree stump.


In Canada, the Mapleleaf Mussel is found in Manitoba and in southwestern Ontario. In Ontario, this species is found in several large rivers that drain into Lake St. Clair and Lake Erie including the Sydenham, Ausable, Grand, and Thames and Welland rivers. The species has disappeared from Lake Erie and the Detroit and Niagara rivers.


The Mapleleaf Mussel is usually found in medium to large rivers with slow to moderate currents and firmly packed sand, gravel, or clay and mud bottoms. It also lives in lakes and reservoirs. Mussels filter water to find food, such as bacteria and algae. Mussel larvae must attach to a fish, called a host, where they consume nutrients from the fish body until they transform into juvenile mussels and then drop off. In Canada, the fish host of the Mapleleaf Mussel is the Channel Catfish. Presence of the fish host is one of the key features determining whether the body of water can support a healthy mussel population.


The main threats to the Mapleleaf Mussel are habitat destruction largely due to pollution and siltation, which wash into rivers from nearby agricultural and urban developments. The Zebra Mussel, which is an invasive species from Europe, is a serious threat because it attaches to other mussels and can kill them by interfering with breathing, feeding, excretion and movement. Conditions that threaten the fish host species also threaten the Mapleleaf Mussel.


The Mapleleaf Mussel is protected under Ontario’s Endangered Species Act.

What You Can Do to Help the Mapleleaf Mussel

  • The Ministry of Natural Resources tracks species at risk such as the Mapleleaf Mussel. 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).
  • 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.
  • Private land owners have a very important role to play in species at risk recovery. If you find Mapleleaf Mussel 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.
  • 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.

Did you know?

The Mapleleaf Mussel depends on the channel catfish to survive. By attaching itself to the gills of the catfish, the mussel larvae consume nutrients from the fish until they transform into juvenile mussels and drop off.

Did you know?

The Mapleleaf Mussel has a lifespan averaging 22 years. A few individual mussels collected from Manitoba were 64 years old!

Did you know?

Mussels are indicators of environmental health. Because they have complex life cycles, are long-lived and eat by filtering water and its pollutants, mussels provide a snapshot of how healthy our waterways are.

Did you know?

Aboriginal people harvested mussels for food. They also used the shells 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.