Plants and Animals
Sphaerium fabale River fingernail clam
Key Characteristics
The river fingernail clam has a dull yellow to brown, laterally compressed and rounded shell reaching a length of about .5 inches. The shell is finely striated near the low and somewhat pointed beak, becoming coarsely and unevenly striated toward the ventral margin.
Status and Rank
US Status: No Status/Not Listed
State Status: SC - Special Concern (rare or uncertain; not legally protected)
Global Rank: G5 - Secure
State Rank: SNR - Not ranked
Occurrences
| County | Number of Occurrences | Year Last Observed |
|---|---|---|
| Allegan | 4 | 1947 |
| Calhoun | 3 | 1953 |
| Cass | 1 | 1956 |
| Eaton | 3 | 1927 |
| Ingham | 6 | 1962 |
| Jackson | 2 | 1941 |
| Kalamazoo | 1 | 1935 |
| Livingston | 2 | 1962 |
| Ottawa | 1 | 1934 |
| Saginaw | 2 | 1941 |
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.
Habitat
This species prefers coarse sand or gravel in both creeks and rivers (Herrington 1962). It has also been found in the Great Lakes (Mackie 2007).
Natural Community Types
- Headwater stream (1st-2nd order), riffle
- Headwater stream (1st-2nd order), pool
- Mainstem stream (3rd-4th order), pool
- Mainstem stream (3rd-4th order), run
- River (5th-6th order), pool
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.
Management Recommendations
Invading zebra mussels can outcompete pea clams for food, and have been linked to drastic declines of this group in the Great Lakes (Lozano et al. 2000, Nalepa et al. 1998). Controlling the spread of zebra mussels by cleaning boat hulls, trailers, and scuba/fishing gear before moving between waterbodies will benefit the river fingernail clam. The pea clam family is especially sensitive to chemical pollutants (Zischke and Arthur 1987), heavy metals and low dissolved oxygen conditions (Kullman et al. 2007). Taking steps to improve water quality should be part of any effort to manage for benthic macroinvertebrates. 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.
Active Period
Spawning from first week of June to fourth week of June
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).
References
Survey References
- Murphy, B.R. and D.W. Willis, eds. 1996. Fisheries Techniques, 2nd ed. American Fisheries Society, Bethesda. 732pp.
Technical References
- Bailey, R.M., W.C. Latta, and G.R. Smith. 2004. An Atlas of Michigan Fishes. Museum of Zoology, University of Michigan, No. 192, Ann Arbor. 215p.
- Evers, D.C. 1994. Endangered and Threatened Wildlife of Michigan. The University of Michigan Press, Ann Arbor. 412pp.
- Hubbs, C.L. and K.F. Lagler. 2004. Fishes of the Great Lakes region, revised edition. Rev.ed. G.R. Smith. The University of Michigan Press, Ann Arbor MI. 276pp.
- Scott, W.B. and E.J. Crossman. 1973. Freshwater fishes of Canada. Bulletin 184, Fisheries Research Board of Canada, Ottawa. 966pp.
- Smith, P.W. 1961. The amphibians and reptiles of Illinois. Illinois Natural History Survey, Carbondale. Bulletin No. 28. 298 pp.
- Trautman, M.B. 1981. The Fishes of Ohio. Ohio State University Press, Columbus. 782pp.