Sphaerium corneum
European pea clam

Key Characteristics

The European pea clam has a thin, oval-shaped, light brown to gray glossy shell of an average .3 inches in length. The shell is very inflated, being nearly as high as it is long, and finely striated dorsally, becoming ventrally more coarse. The beak is centrally located, low and broad.

Status and Rank

  • State Status: SC
  • State Rank: SNR
  • Global Rank: G5


No known occurrences in Michigan

Updated 5/15/2018. 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.


The European pea clam prefers eutrophic, slow moving waters of rivers and lakes with soft mud or sand substrates (Kipp and Benson 2011).

Specific Habitat Needs

Eutrophic needed in Mainstem Stream (3rd-4th order), Run, River (5th-6th order), Pool, River (5th-6th order), Run, 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.


As is common with freshwater mollusks in general, the European pea clam has shown high rates of absorption and bioaccumulation of chemical pollutants found in many herbicides and pesticides (Boryslawskyj et al. 1987, Heinonen et al. 1997). Heavy metals and increased sedimentation from agricultural/urban runoff also pose a threat, and maintainting high water quality should be a priority. Monitoring and mitigation for resident aquatic organisms should be put in place before major alterations to habitat  such as river impoundment, dredging, or construction are undertaken. Invasions of zebra mussels, which outcompete pea clams for important food items, have been related to population declines in the Great Lakes region (Lozano et al. 2000, Nalepa et al. 1998). Preventing the spread of zebra mussels by cleaning boat hulls, trailers, and scuba/fishing gear before moving between waterbodies, will benefit this species.

Survey Methods

Peaclams are best surveyed for by collecting with a grab sampler, such as an Ekman or Peterson grab, or dip net. Collected samples are washed through sieves with a fine mesh (.40 mm openings) in order to retain the smallest individuals. Light-duty forceps can be used to hand-pick peaclams from debris (Mackie 2007).

Page Citation

Michigan Natural Features Inventory. 2007. Rare Species Explorer (Web Application). Available online at http://mnfi.anr.msu.edu/explorer [Accessed Aug 17, 2018]


Survey References

Technical References

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