Wabash Pigtoe
NDGF
The shell is up to 3 inches in length and the shape is variable, but generally thick, compressed, and triangular. Younger individuals are yellow in color with faint green rays, becoming dark brown with age.
Status in North Dakota
Year-round resident and can be locally common.
Range Map
Wabash pigtoe range in North Dakota.
Reason for SWAP Designation
This species is regionally or globally imperiled.
Changes in land use in/around rivers including agriculture and impoundments have impacted this species.
Threats
Impoundment of the Red River and its tributaries have changed the flow regime and increased sediment deposits making many areas in the river unsuitable for the Wabash Pigtoe.
Impoundments also block host fish movement necessary for this species’ reproduction and dispersal.
Agricultural practices, wetland drainage, runoff, and erosion within the basin have reduced suitable habitat and degraded water quality.
The Wabash Pigtoe is considered a commercially valuable species.
It is presently illegal to collect mussels for commercial use in North Dakota, but this practice may occur in parts of its range, which may contribute to an already declining population.
The release of water from Devils Lake changing the water chemistry of the Sheyenne River is a potential threat.
Research and Monitoring
A monitoring protocol for mussels has been developed by the North Dakota Game and Fish Department (NDGF) under the State Wildlife Grant Program with increased implementation as a future goal.
Additionally, the North Dakota Department of Environmental Quality (NDDEQ) conducts biological monitoring surveys on State waters as part of their Index of Biotic Integrity (IBI) development.
Valley City State University (VCSU) conducted a twophase population survey of mussels in 2008-2010 and began another evaluation in 2024.
Management Recommendations
- Develop/maintain buffers along riparian areas.
- Partner with local, state, and federal entities to limit chemical use in/near aquatic habitats.
- Continue partnering with local, state, and federal entities to maintain instream flows.
- Continue partnering with local, state, and federal entities to reduce wetland drainage.
- Remove river impoundments where possible.
- Encourage efficient use of pesticides.
Primary Geological Regions
Habitat Associations
Habitat Use
Primarily found in medium to large rivers with gravel substrate.
The Wabash Pigtoe is found only in the Red and Sheyenne River drainages with the highest concentrations throughout the Sheyenne River in Ransom County.