Share your observations

Share your observations of plants or non-game animals with the Natural Heritage Inventory

Rare animals
Find rare and non-game animals.
Rare plants
Learn about plants on the Natural Heritage Working List.
Rare lichens
Discover Wisconsin's lichens.
Natural communities
Explore Wisconsin's natural communities.
Other features
Discover unique resources.
Eagle license plate

Help care for rare plants and animals by ordering an Endangered Resources plate.

Contact information
For information on Wisconsin's rare vertebrate animals, contact:
Rich Staffen
Conservation Biologist
For information on Wisconsin's rare invertebrates, contact:
Jay Watson
Conservation Biologist

Ebonyshell (Fusconaia ebena)



Ebonyshell (Fusconaia ebena), listed as Endangered, is is found in the western and southern part of Wisconsin in large rivers and is usually on a gravel, sand, or mud bottom in water at least six feet deep where the current is swift. Only very old relic individuals have been found since 1920. Although five fish have been reported as hosts, it is believed that the skipjack herring was the primary host.

State status

Status and Natural Heritage Inventory documented occurrences in Wisconsin

The table below provides information about the protected status - both state and federal - and the rank (S and G Ranks) for Ebonyshell (Fusconaia ebena). See the Working List Key for more information about abbreviations. Counties shaded blue have documented occurrences for this species in the Wisconsin Natural Heritage Inventory database. The map is provided as a general reference of where occurrences of this species meet NHI data standards and is not meant as a comprehensive map of all observations.

Note: Species recently added to the NHI Working List may temporarily have blank occurrence maps.

Documented locations of Fusconaia ebena in the Natural Heritage Inventory Database as of July 2015.
Summary Information
State StatusEND
Federal Status in Wisconsinnone
State RankS1
Global RankG4G5
Tracked by NHIY

Species guidance

Note: a species guidance document is not available at this time. Information below was compiled from publication PUB-ER-085-99 (now out-of-print).

Identification: Shell is subelliptical, thick, and inflated. Epidermis is dark brown or black and without rays. In young shells the epidermis is yellowish followed by bright green and brown. Beaks are elevated and turned forward. Posterior end rounded, dorsal margin evenly curved, and the surface has many concentric ridges. Length to 4 inches (10.2 cm) or more.

Habitat: Inhabits large rivers and is usually on a gravel, sand, or mud bottom in water at least six feet deep where the current is swift.

State Distribution: Occurs in the Mississippi River, the lower Wisconsin and the St.Croix.

Phenology: Host fish is skipjack herring (Alosa chrysochloris). Breeding season is June to September. Black crappie (Pomoxis nigromaculatus), white crappie (P. annularis), and largemouth bass (Micropteris salmoides) have been used by the mussels in June as well.

Management Guidelines: The primary host fish for this species, the skipjack herring, has nearly been eliminated in the upper Mississippi due to locks and dams restricting migration from the Gulf of Mexico. Prior to the building of the locks and dams, the ebony shell was the most abundant species in the Mississippi River. It is rarely, if ever, encountered today. It was used extensively for the pearl button industry because of its high quality, thick "mother-of-pearl" shell. Habitat destruction and river pollution have resulted in mussel declines. Protection of habitat and improvements in water quality along with restriction of dredging, impoundments, sand and gravel mining, and navigational improvements would benefit this species. The development of fish runways to facilitate the movement of host species through or around dams could help to protect the ebony shell.




Photo ©  Illinois Natural History Survey.

Wildlife Action Plan

Wisconsin Wildlife Action Plan graphic

Natural community (habitat) associations

The table below lists the natural communities that are associated with Ebonyshell. Only natural communities for which Ebonyshell is "high" (score=3) or "moderate" (score=2) associated are shown. See the key to association scores for complete definitions. Please see the Wildlife Action Plan to learn how this information was developed.

Natural community Score
Warmwater rivers 3

Ecological landscape associations

The table below lists the ecological landscape association scores for Ebonyshell. The scores correspond to the map (3=High, 2=Moderate, 1=Low, 0=None). For more information, please see the Wildlife Action Plan.

This map shows the probability of Ebonyshell occurring in each of Wisconsin's Ecological Landscapes.  Actual scores can be found in the table to the left.

Back to Top

Landscape-Community combinations of highest ecological priority*

Ecological priorities are the combinations of natural communities and ecological landscapes that provide Wisconsin's best opportunities to conserve important habitats for a given Species of Greatest Conservation Need. The 10 highest scoring combinations are considered ecological priorities and are listed below. More than 10 combinations are listed if multiple combinations tied for 10th place. For more information, please see the Wildlife Action Plan.

* Ecological priority score is a relative measure that is not meant for comparison between species. This score does not consider socio-economical factors that may dictate protection and/or management priorities differently than those determined solely by ecological analysis. Further, a low ecological priority score does not imply that management or preservation should not occur on a site if there are important reasons for doing so locally.

Back to Top

Issues/threats and conservation actions

Conservation actions respond to issues or threats, which adversely affect species of greatest conservation need (SGCN) or their habitats. Besides actions such as restoring wetlands or planting resilient tree species in northern communities, research, surveys and monitoring are also among conservation actions described in the WWAP because lack of information can threaten our ability to successfully preserve and care for natural resources.

Threats/issues and conservations actions for rare animals

Back to Top

Last revised: Thursday, October 08, 2020