Ligumia nasuta
Eastern pondmussel

Key Characteristics

The Eastern pondmussel is a medium to large (to 6 inches, average about 3 inches), elongate mussel with a thin but sturdy, greenish-yellow to brown shell, with narrow green rays sometimes visible. Identifying features include a bluntly pointed posterior end, straight dorsal and curved ventral margins, and a low, wide beak. The nacre varies in color from white to iridescent pinks and blues.

Status and Rank

  • State Status: E
  • State Rank: S2
  • Global Rank: G4


County NameNumber of OccurrencesYear Last Observed
Presque Isle12005
St. Clair72011
St. Joseph1
Distribution map for Ligumia nasuta

Updated 1/31/2017. Information is summarized from MNFI's database of rare species and community occurrences. Data may not reflect true distribution since much of the state has not been thoroughly surveyed.


Preferring fine sand to mud substrates, the Eastern pondmussel inhabits lakes and ponds, as well as slackwater areas of canals, rivers and streams (Metcalfe-Smith and McGoldrick 2007).

Specific Habitat Needs

Sandy substrate needed in Mainstem Stream (3rd-4th order), Pool, Inland Lake, Littoral, Benthic, Inland Lake, Pelagic, Benthic, Great Lake, Littoral, Benthic, Great Lake, Pelagic, Benthic

Natural Community Types


For each species, lists of natural communities were derived from review of the nearly 6,500 element occurrences in the MNFI database, in addition to herbarium label data for some taxa. In most cases, at least one specimen record exists for each listed natural community. For certain taxa, especially poorly collected or extirpated species of prairie and savanna habitats, natural community lists were derived from inferences from collection sites and habitat preferences in immediately adjacent states (particularly Indiana and Illinois). Natural communities are not listed for those species documented only from altered or ruderal habitats in Michigan, especially for taxa that occur in a variety of habitats outside of the state.

Natural communities are not listed in order of frequency of occurrence, but are rather derived from the full set of natural communities, organized by Ecological Group. In many cases, the general habitat descriptions should provide greater clarity and direction to the surveyor. In future versions of the Rare Species Explorer, we hope to incorporate natural community fidelity ranks for each taxon.

Feel free to send questions and comments to Brad Slaughter at


Maintaining habitat integrity is essential to the survival of the Eastern pondmussel, and mussels in general. Dredging, impoundments, construction and dam removal negatively affect this species. Where these activities occur, monitoring to assess impacts, and mitigation measures such as relocation of potentially affected specimens, should be carried out. Healthy populations of host fish are critical to the maturation and dispersal of glochidia, and should also be managed for. As unionid mussels have shown particular sensitiviy to pollutants such as ammonia (Wang et al. 2007), chlorine (Valenti et al 2006), and heavy metals (March et al. 2007, Valenti et al. 2005, Wang et al. 2007), high water quality standards must be met. The treatement of lake areas with herbicides and pesticides containing copper should be avoided where Eastern pondmussel is present.  Non-point source pollution and altered stream hydrology should also be addressed to ensure the viability of unionid mussel populations.  Zebra mussels attach to native mussels and restrict movement and feeding, eventually causing mortality. The extirpation of entire native mussel communities has often been the result (Schloesser et al. 1996). Preventing the spread of zebra mussel adults and larvae by cleaning boat hulls, trailers, scuba and fishing gear, is critical in maintaining Eastern pondmussel populations.

Active Period

Gravid from first week of August to fourth week of May

Survey Methods

Visual and tactile search using scuba or glass-bottom buckets. Tactile search (by hand) is especially important where water turbidity and pebbles/rocks make visual detection difficult. After identification, live mussels should be planted back into the substrate anterior end down. Surveys should not take place after heavy rains or during periods of high water as these conditions can make detection much more difficult.  Methods of documenting survey effort include: searching a large measured area, e.g. 128m2; taking multiple quadrat samples; and recording search time (person hours).  For all methods, at least some excavation of substrate (by hand, 5-10cm down) should be done to detect buried mussels.  Searching a large measured area or timed searches are generally better for detecting rare species and generating a species list than quadrat sampling.  These two methods allow more types of microhabitats and a larger area to be covered.  Quadrat sampling is better suited for documenting changes in density and other statistical analyses at the site level (Strayer and Smith 2003).

Page Citation

Michigan Natural Features Inventory. 2007. Rare Species Explorer (Web Application). Available online at [Accessed Apr 28, 2017]


Technical References

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