Crayfishes of Georgia Overview List of Georgia Species Species Lists by Drainage Crayfish Identification Keys by Drainage Ecology and Life History Links and Other Useful Information Glossary

cambarus extraneus


Scientific Name:  Cambarus (Puncticambarus) extraneus Hagen

Rarity Ranks:  G2/S2

State Legal Status:  Threatened

Federal Legal Status:  None

Description:  The carapace of the Chickamauga Crayfish is mottled brownish and tan while the abdomen has an obvious striped pattern.  This pattern consists of a pale longitudinal stripe running down the middle of the abdomen, bordered on each side by a dark stripe.  Each dark stripe is bordered laterally by a light stripe.  The rostrum is long and pointed with marginal spines or tubercles.  The areola is wide and there is a single cervical spine on each side of the carapace.  This species reaches a maximum total body length of about 100 mm (4 in). 

Similar Species:  The Tanback Crayfish (Cambarus girardianus) occurs with Chickamauga Crayfish and has a striped pattern on the abdomen.  However, the Tanback Crayfish has a medial dark stripe, while the Chickamauga Crayfish has a medial light stripe.  Additionally, the claws of the Tanback Crayfish have a gap between the fingers even when the claw is closed whereas the fingers of the Chickamauga Crayfish touch throughout their length when the claw is closed.

Habitat:  The Chickamauga Crayfish is usually found underneath rocks or in leaf material and woody debris in slow moving to moderately flowing sections of small streams.

Diet:  No studies of the Chickamauga crayfish are known.  Crayfishes are considered opportunistic omnivores and likely feed on live and decaying vegetation, aquatic insects, small fishes, and dead animal matter.

Life History:  Male Chickamauga Crayfish in reproductive condition have been found in April, May, and October.  The smallest breeding male from Georgia is 48 mm (1.9 in); females with eggs or young have not been collected.  A mating pair was seen in late April (Hobbs 1981).

Survey Recommendations:  Since this species is usually found in swift water, it is most easily collected by holding a net perpendicular to the current downstream of a large rock, then lifting the rock and disturbing the substrate beneath it.  If a crayfish is hiding underneath the rock, it will likely move into the net.  Shocking downstream into a seine net with a backpack electroshocker is also effective.  Minnow traps baited with dog- or cat food set overnight may work as well. 

Range:  The Chickamauga Crayfish is known only from the South Chickamauga Creek system in Catoosa, Walker, and Whitfield counties of Georgia and Hamilton County, Tennessee (Hobbs 1989).  All of these locations lie in the Ridge and Valley physiographic province.  It has been collected in about 15 locations in the Georgia portion of its range (Hobbs 1981). 

Threats:  Small range size makes this species vulnerable to extirpation from the state.  Heavy sedimentation resulting from poor development and land management practices may cover substrates and other daytime hiding places on which crayfishes rely to avoid predation.  The introduction of non-native crayfishes is a threat to all native crayfishes.

Conservation and Management Recommendations:  Conserving populations of the Chickamauga crayfish will require general watershed level protection measures, including the protection of riparian zones, control of sediment and nutrient runoff from farms and construction sites, and limiting the amount of impervious cover (e.g., pavement) within occupied watersheds.  Non-native crayfishes should never be used for bait.  Instead, anglers should use crayfishes collected from the river system they will be fishing in and should never release unused bait crayfish back into Georgia waters. 

Selected References:

Hagen, H. A. 1870. Monograph of the North American Astacidae. Illustrated Catalogue of the Museum of Comparative Zoology at Harvard College. 3:1-119

Hobbs, H. H., Jr. 1981.  The crayfishes of Georgia.  Smithsonian Contributions to Zoology, 318:1-549. 

Hobbs, H. H., Jr.  1989. An illustrated checklist of the American crayfishes (Decapoda: Astacidae, Cambaridae, and Parastacidae).  Smithsonian Contributions to Zoology, 480:1-236

Taylor, C. A., G. A. Schuster, J. E. Cooper, R. J. DiStefano, A. G. Eversole, P. Hamr, H. H. Hobbs III, H. W. Robison, C. E. Skelton, and R. F. Thoma. 2007.  A reassessment of the conservation status of crayfishes of the United States and Canada after 10+ years of increased awareness. Fisheries 32:8:372-389.

cambarus extraneus map

Date Compiled or Updated:  September 2012

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