Common Name: BLACKBARRED CRAYFISH
Scientific Name: Cambarus (Jugicambarus) unestami Hobbs and Hall
Rarity Ranks: G2/S2
State Legal Status: Threatened
Federal Legal Status: None
Description: The overall color of the Blackbarred Crayfish is brownish with dark barring on the abdomen giving the impression of longitudinal stripes. The areola is wide and the rostrum tapers gradually. There are two rows of tubercles on the mesial margin of the palm. This species reaches a maximum total body length of about 80 mm (3.1 in.).
Similar Species: The Blackbarred Crayfish has been collected with the similar Mountain Midget Crayfish (Cambarus parvoculus) a few times. The latter has a slightly narrower areola and a fairly blunt rostrum compared to the longer tapered rostrum of the Blackbarred Crayfish. Additionally, the Blackbarred Crayfish has a mottled appearance while the Mountain Midget Crayfish is more uniformly colored.
Habitat: The Blackbarred Crayfish is usually collected in medium-sized streams from beneath rocks or within leaf litter in moderate to swift current.
Diet: No studies of the Blackbarred Crayfish are known. Crayfishes are considered opportunistic omnivores and likely feed on live and decaying vegetation, aquatic insect larvae, small fishes, and dead animal matter.
Life History: Male Blackbarred Crayfish in reproductive condition have been collected in April, May, October, and November and females carrying eggs were found in April and May. The number of eggs for two individuals ranged from 124-194, with egg diameters averaging 2.5 mm. The smallest breeding male is about 54 mm (2.1) and the smallest female with eggs about 65 mm (2.6) in length (Hobbs 1981).
Survey Recommendations: Since this species is usually found in moving 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.
Range: The Blackbarred Crayfish is known from the Cumberland Plateau and Ridge and Valley physiographic provinces in tributaries of Chattanooga, Cole City, and Lookout creeks in northwestern Georgia and extreme northeastern Alabama. These streams are in the Tennessee River drainage. It has also been taken from tributaries to the Little River, which is part of the Coosa River system.
Threats: The small range size of this species makes it 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 Blackbarred 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.
Hobbs, H. H., Jr. 1981. The crayfishes of Georgia. Smithsonian Contributions to Zoology 318:1-549.
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.
Date Compiled or Updated: September 2012