Mapleleaf (Saskatchewan - Nelson Population)

Quadrula quadrula

SARA Status
No Status
NS
Special Concern
SC
Threatened
TH
Endangered
EN
Extirpated
EX

SARA Status

  • No Status NS
  • Special Concern SC
  • Threatened TH
  • Endangered EN
  • Extirpated EX
COSEWIC Status
Not at Risk
NR
Special Concern
SC
Threatened
TH
Endangered
EN
Extirpated
EX

COSEWIC Status

  • Not at Risk NR
  • Special Concern SC
  • Threatened TH
  • Endangered EN
  • Extirpated EX

Description

The Mapleleaf (Quadrula quadrula) is a medium-sized freshwater mussel. This mussel is found in both Manitoba and Ontario, and is named for its somewhat square shape, which resembles a maple leaf. It has the following features:

  • thick, square, yellowish-green (juvenile) or mostly brown (adult) shell;
  • two rows of raised nodules form a v-shape along the outside of the shell;
  • inside of the shell (nacre) is pearly white;
  • raised part at the top of the shell (beak) is small and slightly raised above the hinge line;
  • heavy hinge teeth;
  • well-defined growth lines in young mussels, crowded and difficult-to-discern growth lines in adults; and
  • adults can grow to 12 cm in length.

Habitat

The majority of Mapleleaf are found in the United States, with a range that includes Texas to Alabama, the Great Lakes drainage basin in Minnesota and Wisconsin to New York, and the Red River drainage basin in Minnesota and North Dakota.

In Canada, Mapleleaf populations are separated into two distinct groups, called “designated units” (DUs), based on genetic and geographic differences: the Saskatchewan-Nelson populations (DU1) and the Great Lakes-Western St. Lawrence populations (DU2). Saskatchewan-Nelson populations are located in Manitoba along the Red River and the lower reaches of its tributaries, the Assiniboine River and Lake Winnipeg. The Great Lakes-Western St. Lawrence populations are found in the Great Lakes-St. Lawrence watershed in Ontario and appear to be confined to the Sydenham, Ausable, Grand, Thames, Bayfield and Welland rivers, as well as the mouth of 20 Mile Creek at Lake Ontario in Jordan Harbour.

In Manitoba, this mussel is in decline and appears to be limited to the Red, Assiniboine, Roseau and Bloodvein rivers.

In Canada, the Mapleleaf is usually found in medium-to-large rivers with slow-to-moderate currents and firmly packed sand, coarse gravel or clay/mud bottoms (substrates). It is a long-lived species; mussels from the Manitoba populations have lived up to 64 years of age, but the average age is 22 years. The “brooding period” is short: spawning likely occurs in late spring and the larvae (glochidia) are released by early summer. Like most other freshwater mussels, the Mapleleaf glochidia are parasitic on fish. In this case, the female Mapleleaf releases packets of glochidia that look similar to the food of their host fish. When the fish takes a bite, the glochidia are released into its mouth and flow through its gills. Here they will remain until they reach their juvenile, free-living stage and drop off onto the substrate below. Adult mussels are essentially sessile and may move only a few metres per year along the river or lake bottom. In Canada, the Channel Catfish (Ictalurus punctatus) is the most likely host fish.Like all species of freshwater mussels, the Mapleleaf filters its food from the water. Bacteria and algae are its primary food sources.

Threats

Mapleleaf populations in Canada are threatened by invasive species, habitat loss and degradation, and siltation (more sediment in the water), which can bury, smother and starve filter-feeding mussels. In Manitoba, deteriorating water quality due to non-point source pollution and possible invasion of Zebra Mussels (Dreissena polymorpha) are major concerns.

Further Information

For more information, visit the Species at Risk (SARA) Public Registry Profile.

Text Sources: COSEWIC assessment and status report on the Mapleleaf Mussel Quadrula quadrula (Saskatchewan-Nelson population and Great Lakes-Western St. Lawrence population), 2006; Metcalfe-Smith et al. Photo Field Guide to the Freshwater Mussels of Ontario, 2005.

Mapleleaf (Saskatchewan - Nelson Population)

Mapleleaf

Mapleleaf

Scientific Name: Quadrula quadrula
SARA Status: Endangered
COSEWIC Status: Threatened
Region: Manitoba

Map showing distribution of Mapleleaf, Saskatchewan-Nelson populations in Canada as described in the following paragraphs

Map showing distribution of Mapleleaf, Saskatchewan-Nelson populations, in Canada.

Related information

Mapleleaf mussels

Photo credit: Fisheries and Oceans Canada

Did You Know?

Freshwater mussels are molluscs, soft-bodied animals without a skeleton (invertebrates) that live on the bottom of streams, rivers, lakes and ponds. They use a muscular foot to burrow and crawl and have a pair of hinged shells. Mussels are filter feeders — nature’s water purifiers — and are food for other wildlife, like fishes, otters, mink, muskrats and some birds. They are also among the most endangered creatures in the world.