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Creaserinus fodiens (Cottle, 1863)
Digger Crayfish
Federal Protection: No US federal protection
State Protection: No Georgia state protection
Global Rank: G5
State Rank: S3
Element Locations Tracked in Biotics: No
SWAP 2015 Species of Greatest Conservation Need (SGCN): No
SWAP 2025 Species of Greatest Conservation Need (SGCN): No
2025 SGCN Priority Tier: None
Element Occurrences (EOs) in Georgia: 0
Habitat Summary for element in Georgia: Complex burrows in low wet areas; may be found in open waters such as streams and ditches in the Spring
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). Note: Creaserinus was formerly a subgenus of the genus Fallicambarus but was elevated to the genus level by Crandall and De Grave (2017).
The most similar species that are likely to occur with the Digger Crayfish are Devil Crawfish, Lacunicambarus diogenes and Ambiguous Crayfish, Cambarus 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 is seen on the Digger Crayfish.
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.
Similar to other crayfishes, Bovbjerg (1952) reported that this species ate a variety of plant and animal materials.
Burrowing crayfishes inhabit a system of tunnels that may be very complex with several openings to the surface. Openings to the tunnels are often marked by piles of dirt or mud pellets (chimneys). Depending on the soil type and moisture content, these chimneys can reach heights of 15 cm (6 inches) or more. These crayfishes are typically confined to their burrows, but a male must leave its burrow to search for females during the reproductive season. As mentioned above, they may also forage near the opening of their burrow. Active burrows with fresh soil are seen from late spring to late fall, particularly after rain events. During the dry part of the summer, burrow openings may be plugged to help conserve moisture in the burrow. Reproduction probably occurs during the spring and fall, but males in reproductive condition may be found at any time during the year. It is very rare to find more than one adult crayfish in the same burrow. When a female crayfish releases her eggs, she attaches them to her swimmerets and is said to be “in berry.” Upon hatching, the juvenile crayfish are attached to the mother by a thread. After the juveniles molt for the second time, they are free of the mother, but stay close and will hold on to her for some time. Multiple juveniles are occasionally found in a single burrow. Eventually they move off on their own. Crayfishes molt 6 or 7 times during their first year of life and most are probably able to reproduce by the end of that year. They molt once or twice a year for the remainder of their lives. Although it is difficult to study burrowing crayfishes, some researchers believe they may live as long as 10 years. Only 9 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).
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.
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).
Activities that destroy burrows or alter hydrology in the vicinity of burrows threaten this and other burrowing species.
Although the species is known from only a few locations, there is limited growth in this region of the state, and therefore is considered stable.
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. Doctoral Dissertation. University of Illinois, Urbana-Champaign, IL. 158 pp.
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.
Crandall, K.A., and S. De Grave. 2017. An updated classification of the freshwater crayfishes (Decapoda: Astacidea) of the world, with a complete species list. Journal of Crustacean Biology 2017:1-39.
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 98:223–231.
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 10:452–483.
Pflieger, W.L. 1996. The Crayfishes of Missouri. Missouri Department of Conservation, Jefferson City, MO. 152 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 32:372–389.
Christopher E. Skelton
C. Skelton, 2012: original account
C. Skelton, February 2019: general update of account.
DW, August 2019: added Lukhaup photo