Ozark Crayfish

Media
Photo of an Ozark crayfish.
Scientific Name
Faxonius ozarkae (formerly Orconectes ozarkae)
Family
Cambaridae (freshwater crayfish) in the order Decapoda (shrimp, crabs, and lobsters)
Description

The Ozark crayfish is light brown to reddish brown with numerous black specks on the pincers and often on the abdomen as well. The pincers are broad and powerful. Two dark saddle marks cross the body: one near the back of the head, the other where the carapace joins the thorax. There is an hourglass-shaped area (areola) along the midline of the carapace.

Similar species: Some common, superficially similar species within the range of this crayfish are the golden crayfish and the ringed crayfish. Both of these species lack conspicuous blackish specks on the pinchers and abdomen, and the ringed crayfish has prominent brown or black rings on the fingers near their tips. The very similar woodland crayfish, mostly found in the Black River system, is not known to occur in the same river drainages.

Size

Adult length: about 1 to 3½ inches.

Where To Find
Ozark Crayfish Distribution Map

The Ozark crayfish occurs widely in the southern Ozarks, from Roaring River and Flat Creek in Barry County eastward to the Little Black River in Ripley County. It seems to be absent from the North Fork River and Bryant Creek. It also occurs in parts of Arkansas.

Invariably found in streams, usually over silt-free, rocky substrates, in cavities beneath rocks and boulders, or along the margins of dense beds of water willow (Justicia spp.) adjacent to swift riffles and runs. It has been reported from moist burrows under deeply seated rocks in dry stream beds. This species excavates cavities under rocks.

Crayfish are generally omnivores, eating a wide variety of plant and animal materials.

Life Cycle

Like most other Ozark stream crayfish, this species breeds in the fall and produces eggs in early spring. Females apparently retire to deep cavities or other hidden places when bearing eggs or young. The young are about 1 to 1½ inches long by the end of their first growing season, and most of them mature during their second year of life. The total lifespan is probably about 2½ years.

In addition to feeding many types of wildlife, crayfish provide food for many species that humans hunt and fish. Crayfish commonly serve as fish bait, and many people eat crayfish, too. Crayfish are fascinating, creatures and are part of our rich native heritage.

Their opportunistic, omnivorous feeding makes crayfish an important link in the food chain between plants and vertebrates, breaking down plant and other materials that are resistant to decomposition. Crayfish in turn are an important food for many other animals.

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About Aquatic Invertebrates in Missouri
Missouri's streams, lakes, and other aquatic habitats hold thousands of kinds of invertebrates — worms, freshwater mussels, snails, crayfish, insects, and other animals without backbones. These creatures are vital links in the aquatic food chain, and their presence and numbers tell us a lot about water quality.