Common Name: DIGGER CRAYFISH
Scientific Name: Fallicambarus (Creaserinus) fodiens Cottle
Rarity Ranks: G5/S3
State Legal Status: None
Federal Legal Status: None
Description: The overall color of the Digger Crayfish is brown to olive with darker mottling. The abdomen has a striped appearance with a pale center line flanked by darker pigment. There are two rows of tubercles along the mesial margin of the palm and the areola is obliterated. The rostrum is fairly broad and tapering and has no marginal spines or tubercles. A small cervical spine or tubercle is present. This species reaches a maximum total body length of about 75 mm (3 in).
Similar Species: The only other Cambarus species that are likely to occur with the Digger Crayfish are the Devil Crawfish, Cambarus diogenes and the Ambiguous Crayfish, C. striatus. Devil Crawfish have more than two rows of tubercles along the mesial margin of the palm and have red coloring on the carapace, abdomen, and claws. Ambiguous Crayfish in this part of the state are a plain orangish brown with no dark mottling. Also, the areola is not quite obliterated as seen on the Digger Crayfish.
Habitat: Complex burrows adjacent to streams and seepage areas, or in low areas where the water table is near the surface of the ground. In the spring, Digger Crayfish may be found in open water such as streams and ditches.
Diet: Similar to other crayfishes, Bovbjerg (1952) reported that this species ate a variety of plant and animal materials.
Life History: Only nine specimens were available to Hobbs (1981) when he wrote the account for this species. Thus, information on the life history of Digger Crayfish in Georgia is limited. He found one male in reproductive condition in June. Across the range of the Digger Crayfish, males in reproductive condition have been collected in every month of the year (Hobbs 1948, Penn and Hobbs 1958, Taylor and Schuster 2004). Females with eggs or young are usually found from late winter into spring, but there are some reports of female carrying eggs in the fall (Brown 1955, Penn and Hobbs 1948). The only male in reproductive condition from Georgia is about 53 mm (2.1 in).
Survey Recommendations: Burrowing crayfishes may be collected by direct excavation of their burrows, by trapping, and during night surveys. Excavating burrows is time consuming and can be very difficult. It also results in destruction of the animals’ burrow. Traps made with PVC pipes or mist nets can be effective, but only when crayfishes are in an active period. Burrowing crayfishes are sometimes captured around the openings of their burrows on damp nights. It is possible to find active burrows from about mid-March to mid-November if the water table is within about 2 feet of the surface of the ground. However, most activity is seen in the spring from mid-March to mid-May and the fall from mid-September to mid-November. Seining or dipnetting in small streams and ditches may yield specimens in the spring.
Range: The Digger Crayfish is one of the most widespread species in North America. It can be found from Texas to Florida, and through the central and eastern United States to Ontario (Hobbs 1989). In Georgia it is only known from about five localities in the southwestern part of the state. One collection was made in the Spring Creek system, while all of the others were in direct tributaries to the Chattahoochee River (Hobbs 1981).
Threats: This species is apparently secure across its range.
Conservation and Management Recommendations: Conserving populations of the Digger 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. Areas with burrows should be protected from land disturbing activities and activities that could alter groundwater resources. Environmental education programs should include information about burrowing crayfishes and encourage protection of burrows.
Bovbjerg, R.V. 1952. Comparative ecology and physiology of the crayfish Orconectes propinquus and Cambarus fodiens. Physiological Zoology 25:34-56.
Brown, P.L. 1955. The biology of crayfishes of central and southeastern Illinois. Unpublished Doctoral Dissertation, University of Illinois, Urbana-Champaign. 158 p.
Cottle, T.J. 1863. On the two species of Astacus found in upper Canada. Canadian Journal of Industry, Science, and Arts, new series, 45:216-219.
Hobbs, H.H., Jr. 1948. A new crayfish of the genus Cambarus from Texas, with notes on the distribution of Cambarus fodiens (Cottle). Proceedings of the United States National Museum 98(3230):223-231.
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.
Penn, G.H. and H.H. Hobbs, Jr. 1958. A contribution toward a knowledge of the crawfishes of Texas (Decapoda, Astacidae). Texas Journal of Science, 10(4):452-483.
Pflieger, W.L. 1996. The Crayfishes of Missouri. Missouri Department of Conservation, Jefferson City, MO.
Taylor, C.A. and G.A. Schuster. 2004. Crayfishes of Kentucky. Illinois Natural History Survey Special Publication 28, Champaign, IL. 219 pp.
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