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Procambarus versutusSly Crayfish
Federal Protection: No US federal protection
State Protection: Rare
Global Rank: G5
State Rank: S1
SWAP High Priority Species (SGCN): Yes
Element Occurrences (EOs) in Georgia: 17
Habitat Summary for element in Georgia: Found in debris in moderately swift streams. Found in root masses and plants.
The Sly Crayfish is dorsally tan or brown with cream and black markings. Striking cream-colored stripes run horizontally along the sides of the carapace and abdomen. The rostrum bears spines lateral to the tip and has a central ridge (carina). There are two distinctive cervical spines on either side of the carapace. The claws are dark, but the tubercles on the claws are even darker. The abdomen is brown and is covered with black blotches; these black markings form a horizontal band with irregular edges along the sides of the abdomen. The areola is 2 to 3 times as long as broad and comprises 24 to 28 percent of the total length of the carapace. Males of this species may reach a maximum total body length of over 90 mm (3.5 in). Mature females are about the same size, but males have notably larger claws.
The Sly Crayfish has a distinctive color pattern in life that makes it easy to distinguish from other crayfishes within in its range. However, it may be difficult to distinguish from preserved specimens of the White Tubercled Crayfish (Procambarus spiculifer). The dark (vs. white) tubercles of the Sly Crayfish are a helpful character. This species is usually found in low pH (acidic) streams, whereas the White Tubercled Crayfish is usually found in streams of near neutral pH.
The Sly Crayfish has been found only in clear, free-flowing streams. During the day they are usually found within debris, aquatic plants (e.g., Golden Club, Orontium aquaticum), and root masses along the banks of sand-bottomed streams. They move out over the sand to forage at night. They may dig simple burrows into the banks of streams.
No studies of the Sly Crayfish diet are known. Crayfishes are considered opportunistic omnivores and are likely to feed on live and decaying vegetation, aquatic insect larvae, small fishes, and dead animal matter.
Stream dwelling crayfishes typically hide during the day and come out at night to feed. Reproduction usually occurs during the spring and fall, but males in reproductive condition may be found at any time during the year. When female crayfish are ready to lay eggs, they usually find a secure hiding place and hence are rarely encountered. When the eggs are released, the female 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. 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 and live about 3 years. The only life history information published for Sly Crayfish is found in notes provided by Hobbs (1981). Hobbs examined only five specimens from Georgia, but in Alabama and Florida he reported males in reproductive condition from all months of the year and egg-bearing females from April to June. Stanton (2006) also collected males in reproductive condition throughout the year in Georgia, but rarely encountered egg-bearing females.
Disturbing the substrate around aquatic plants and debris upstream from a net can be productive, as well as shocking downstream into a seine net with a backpack electroshocker. Because crayfish are typically more active at night, trapping may also be effective.
The Sly Crayfish is distributed within the Chattahoochee River system in Chattahoochee and Marion counties. With the exception of a few small creeks draining directly into the Chattahoochee River from Fort Benning, Georgia, records of the Sly Crayfish are restricted to the Upatoi Creek system where high quality habitat occurs in Pine Knot Creek and other eastern tributaries of Upatoi Creek.
The Sly Crayfish is threatened in Georgia by its small geographic range and land uses within that range that could alter hydrology and water quality. The Chattahoochee County habitat lies within federal property, the Fort Benning Military Reservation. This habitat has been well protected in the past but could be threatened by increased military training occurring on base. Two of the best Marion County localities have been impacted by recent highway construction.
This species is considered to be stable at this time. In addition, Fort Benning has natural resource management programs in place and has the ability to provide considerable protection to this species.
Conserving populations of the Sly Crayfish will require general watershed-level conservation practices, such as protection of riparian zones and adherence to best management practices for forestry, agriculture, and highway construction. Special efforts should be made to protect important populations in Black, Juniper, and Pine Knot creeks and Fort Benning should include this species in future conservation planning efforts. 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. 1976. Crayfishes and shrimps. In: H. Boschung, ed., Endangered and Threatened Plants and Animals of Alabama. Bulletin of the Alabama Museum of Natural History 2:13-20. Page 14.
Hagen, H.A. 1870. Monograph of the North American Astacidae. Illustrated Catalogue of the Museum of Comparative Zoology at Harvard College 3:117 p.
Hobbs, H.H., Jr. 1981. The crayfishes of Georgia, Smithsonian Contributions to Zoology 318:1–549.
Stanton, G.E. 2006. Evaluation of conservation status of six West Georgia, Chattahoochee-Flint River crayfish species. Report to the Georgia Department of Natural Resources, Georgia Natural Heritage Program, Social Circle, GA. 60 p.
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.
George E. Stanton
G. Stanton, 2008: original account
C. Skelton, January 2019: general update of account.