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Recovery Strategy For Northern Riffleshell, Snuffbox, Round Pigtoe, Mudpuppy Mussel and Rayed Bean in Canada [Proposed]

11.  Habitat: Rayed Bean

Habitat Identification:Cummings and Mayer (1992) describe its habitat as “lakes and small to large streams in sand or gravel”. It is occasionally reported from shallow water areas of lakes and large rivers (TNC 1996). For example, historical records show that it has been found along the edges of islands in Lake Erie and the Detroit River. The Rayed Bean is usually found deeply buried in the substrate, among the roots of aquatic vegetation. As a result, this species may not be as sensitive to flow rate fluctuations in its habitat as some other mussel species (TNC 1987). Live specimens encountered in the Sydenham River (Metcalfe-Smith et al.1998; 1999) were found buried in stable substrates of sand or fine gravel, generally in low flow areas along the margins of the river or the edges of small islands.

Currently Occupied HabitatMethods for delineating currently occupied habitat for the Mudpuppy Mussel follow the methods described for the Northern Riffleshell.

Geospatial Description: Currently occupied habitat for the Rayed Bean can be defined as a 50 km reach of the East Sydenham River (Figure 24) and small reach in the North Thames River above London (Figure 25).

Functional Description: Within the area defined under Currently Occupied Habitat only areas meeting the characteristics described below are deemed to represent habitat in need of conservation:

  • permanently wetted and
  • of a stream order greater than 2 and
  • sand or fine gravel with
  • low to moderate flows

Historically Occupied Habitat: The Rayed Bean is historically known from the Detroit River, South Thames River near Dorchester, several locations in the Thames River between London and Chatham and portions of Lake Erie around Pelee Island.


Figure 24 Currently occupied habitat of the Rayed Bean in the Sydenham River.


Figure 25: Currently occupied habitat of the Rayed Bean in the Thames River.