Common Name: VARIABLE CRAYFISH
Scientific Name: Cambarus (Depressicambarus) latimanus (LeConte)
Rarity Ranks: G5/S5
State Legal Status: None
Federal Legal Status: None
Description: The overall color of the Variable Crayfish is light brown to olive with darker mottling. Occasionally the darker pigmentation is so dense on the abdomen that the animal has a striped appearance. The tips of the claws are usually orangish and there are two rows of tubercles along the mesial margin of the palm. The areola is fairly narrow but never obliterated. The rostrum typically tapers, but occasionally has marginal tubercles (even spine-like in juveniles). A single cervical tubercle is usually present and may be a sharp spine on juveniles. This species reaches a maximum total body length of about 75 mm (3 in).
Similar Species: Across its range, the Variable Crayfish is most similar to the Ambiguous Crayfish, Cambarus striatus. According to Hobbs (1981) the two are sometimes impossible to separate. The areola of the Ambiguous Crayfish is typically narrower and rostrum typically shorter than that of the Variable Crayfish. The Common Crayfish, Cambarus bartonii, is a relatively plain looking brownish species with darker mottling but usually has a wider areola and a single row of flattened tubercles on the mesial margin of the palm.
Habitat: The Variable Crayfish is considered a secondary burrower and thus is found in open water of flowing streams as well as burrow complexes along the banks of streams. Within a stream this species is found hiding beneath rocks, within woody debris and leaf litter, and beneath undercut banks.
Diet: Boyce (1969) found that Variable Crayfish are similar to other species by being opportunistic omnivores and likely feed on live and decaying vegetation, aquatic insect larvae, small fishes, and dead animal matter.
Life History: Male Variable Crayfish in reproductive condition have been collected in all months except February, July, and August. Three females carrying eggs were found in April (Bouchard 1978). The smallest male from Georgia is about 64 mm (2.5 in). The largest female specimen collected is about 90 mm (3.5 in) in length (Hobbs 1981).
Survey Recommendations: In the Conasauga River system, flipping rocks within streams should reveal this species. In other portions of the range, the species is apparently restricted to burrows which will have to be excavated or trapped.
Range: The Variable Crayfish is one of the most common and widespread species in Georgia. It is most commonly found in the Piedmont physiographic province and is found in all major river systems there. It is absent from the Tennessee River drainage in the northwestern portion of the state and the Little Tennessee River system. The species penetrates the Coastal Plain in all of the major river systems, but largely disappears in the lower one-third of the state. This species is also known from Alabama, Florida, North Carolina, South Carolina, and Tennessee (Hobbs 1981; 1989).
Threats: This species is apparently secure across its range.
Conservation and Management Recommendations: General watershed level protection measures will help secure the continued existence of the Variable Crayfish in Georgia. These include 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.
Bouchard, R. W. 1978. Taxonomy, ecology, and phylogeny of the subgenus Depressicambarus, with the description of a new species from Florida and redescriptions of Cambarus graysoni, Cambarus latimanus, and Cambarus striatus (Decapoda: Cambaridae). Alabama Museum of Natural History Bulletin, 3:26-60.
Boyce, J. L. 1969. An Ecological Study of Cambarus latimanus (LeConte) and Procambarus spiculifer (LeConte) in the Yellow River of the Altamaha River Basin of Georgia, with Particular Emphasis on Respiration and Tolerance to Low Oxygen. [Unpublished thesis.] 105 + 7 unnumbered pages, 33 figures. Emory University, Decatur, GA.
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.
Date Compiled or Updated: August 2012