Loading profile. Please wait . . .
Cambarus truncatusOconee Burrowing Crayfish
Federal Protection: No US federal protection
State Protection: Threatened
Global Rank: G2
State Rank: S2
SWAP High Priority Species (SGCN): Yes
Element Occurrences (EOs) in Georgia: 11
Habitat Summary for element in Georgia: Complex burrows in sandy clay soil
The overall color of the Oconee Burrowing Crayfish is pale to bright orange. The areola is virtually non-existent and the rostrum is short and broad. The abdomen is obviously narrower than the cephalothorax and the claws may be robust. There are two rows of tubercles along the mesial margin of the palm. This species reaches a maximum total body length of about 68 mm (2.7 in).
No other bright orange crayfish occurs in Georgia.
Complex burrows adjacent to streams or in low areas where the water table is near the surface of the ground.
No studies of the Oconee Burrowing Crayfish Burrower are known and the diet of burrowing crayfishes in general is poorly understood. Crayfishes are considered opportunistic omnivores and likely feed on a variety of items, both plant and animal, living or dead. Burrowing crayfishes may forage around the mouths of their burrows, eat organisms that crawl or fall into the burrow, or eat worms that inadvertently tunnel through a burrow wall.
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. Males in reproductive condition have been collected from February to May and October to November (Hobbs 1981, Roberson et al. 2015); the smallest reproductive male is about 51 mm (2 in) in length (Hobbs 1981). Females with active glair glands were found from March to May and October to November. Four ovigerous females have been collected in the months of April (1) and May (3) and produced about 10, 26, 27, and 31 eggs (Roberson et al. 2015, Skelton unpubl. data).
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. Burrowing crayfishes are sometimes captured around the openings of their burrows on damp nights. Active burrows are found from about mid-March to mid-November if the water table is within about 2 feet of the surface of the ground.
The Oconee Burrowing Crayfish is currently known from 26 locations in five counties in the Oconee River system in middle Georgia. All of these locations are in the Coastal Plain physiographic province.
The small range of this species makes it vulnerable to land disturbing activities around streams and wetlands that could destroy burrows and alter hydrology.
Although this species has a fairly narrow range, there is limited growth in this region of the state. In addition, there are somewhat protected populations on the Beaver Dam Wildlife Management Area (managed by the Georgia Department of Natural Resources) and the Balls Ferry property near Toomsboro (jointly managed by Wilkinson County and Georgia DNR).
If possible, areas with burrows should be protected from land disturbing activities. Additional surveys and life history studies are needed to better define the range of the Oconee Burrowing Crayfish and help predict its response to environmental change. Environmental education programs should include information about burrowing crayfishes and encourage protection of burrows.
Hobbs, H.H., Jr. 1981. The crayfishes of Georgia. Smithsonian Contributions to Zoology 318:1–549.
Roberson, E.K., C.E. Skelton, and C.M. Babb. Life history and distribution of the Oconee Burrowing Crayfish, Cambarus truncatus. Freshwater Crayfish 21:123–130.
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, 2008: original account
C. Skelton, January 2019: general update of account.