The mucket is one of the most widespread and abundant mussels in southern Missouri. Also found in the Salt River, it lives in medium to large rivers in relatively swift water with a stable mix of gravel, sand, and cobble.
Externally, the mucket's shell is thick, heavy, oblong, and moderately inflated. The umbo (beak) is low and slightly above the hinge line. The periostracum (thin outer layer) is yellowish brown, becoming darker with age; green rays may be present.
Inside the shell, the beak cavity is shallow; the pseudocardinal teeth are large, serrate, and slightly elevated; the lateral teeth are bladelike, straight to slightly curved, moderately short, and serrate; the nacre (mother-of-pearl layer) is white, rarely tinged with pink.
For a fuller introduction to Missouri’s native freshwater mussels, and to learn the terms for their anatomy, see their group page.
Similar species: The plain pocketbook’s shell is more inflated, less stout, thinner, more square (in females) or rounded (in males), and has a higher umbo. It may also be confused with the pink mucket, which is a federally endangered species. Other similar species include the sheepnose and the fatmucket.
Adult length: 3–7 inches.
Widespread in southern Missouri; also Salt River. Found in all medium and large streams draining the Salem and Springfield plateaus.
Habitat and Conservation
Medium to large rivers in relatively swift water with a stable mix of gravel, sand, and cobble.
Food
Freshwater mussels consume algae, bacteria, and fine particles of decaying organic matter. They extract nutrients and oxygen from water drawn into the body cavity through a specialized structure called the incurrent siphon; sediment, undigested food, and waste (called pseudofeces) are expelled through the excurrent siphon.
Status
Common. One of the most abundant and widespread freshwater mussels in the southern half of Missouri.
Life Cycle
Males release sperm directly into water. Females downstream siphon sperm into the gill chamber, where eggs are fertilized. Eggs mature into larvae (called glochidia), which discharge into the water and attach to host fish. This species uses smallmouth and largemouth bass, green sunfish, bluegill, crappie, walleye, and several others. The tiny mussel eventually breaks away and floats to the bottom of the stream, and the cycle repeats.
Human Connections
Mussels play important roles in maintaining the health of Missouri’s water resources:
- As food for fish, they are important for Missouri’s fisheries. Small mammals and some birds eat them, as well.
- They filter algae, bacteria, and other particles from the water, improving water quality and cycling nutrients and energy in streams and lakes. Clean water is necessary for people and nature.
- Because mussels are sensitive to habitat disturbance and pollution, they are good indicators of the overall health of aquatic ecosystems and water quality.
The shells of several types of mussels, including this species, were an important resource historically for button manufacture. Some species are still commercially important in the cultured pearl and jewelry industries.
Ecosystem Connections
Mussels play important roles in maintaining the health of Missouri’s water resources:
- As food for fish, they are important for Missouri’s fisheries. Small mammals and some birds eat them, as well.
- They filter algae, bacteria, and other particles from the water, improving water quality and cycling nutrients and energy in streams and lakes. Clean water is necessary for people and nature.
- Because mussels are sensitive to habitat disturbance and pollution, they are good indicators of the overall health of aquatic ecosystems and water quality.
The shells of several types of mussels were an important resource historically for button manufacture. This species is one that was used to make buttons. Some species are still commercially important in the cultured pearl and jewelry industries.
