Mussels and Clams
Benthic Macroinvertebrates
Sensitive Benthos
Moderately Tolerant Benthos
Pollution Tolerant Benthos
Description:
Include the larger pearly naiad mussels, as well as the small fingernail clams, and the European clam (Corbicula). Mussels are large (up to 9 inches in diameter, robust, thick- or thin-shelled, and usually dark in color. Fingernail clams are small (no more than 1/2 inch in diameter), fragile, and are whitish or grayish in color. Corbicula can be larger, 1 to 2 inches in diameter, and light-colored.
Reproduction:
females deposit eggs on top of water where they drift to the bottom.
Adults:
fingernail clams are self-fertilizing, the young developing inside the water tubes of the adult; mussels have a very elaborate and intriguing process; the larvae, called glochidia, develop inside the adult female and are released into the water where they eventually attach onto a host fish; then they parasitize the fish for about two weeks until they drop off and develop on the stream bottom into an adult.
Food:
primarily filter feeders; filter organic debris and plankton out of the water; preyed upon by numerous fish and mammals.
Scientific Name:
Class: Mollusca
Order: Pelecypoda
Indicator Role:
Mussels are sensitive to siltation and low dissolved oxygen. Fingernail clams and Corbicula are opportunistic and can be found in degraded conditions.
Information Source:
McDonald, B., W. Borden, J. Lathrop.1990. Citizen Stream Monitoring: A Manual for Illinois. Illinois Department of Energy and Natural Resources, ILENR/RE-WR-90/18. Springfield, Illinois.
Other Links:
- Field Guide to Freshwater Mussels of the Midwest in Illinois Natural History Survey's Mollusk Collection
- America's Mussels: Silent Sentinels (USFWS)
- Pouch snails, limpets and fingernail clams by the Lackawanna River Corridor ssociation
- Clams and Mussels in Freshwater Benthic Ecology and Aquatic Entomology Homepage S.M. Mandaville from the Soil & Water Conservation Society of MetroHalifax