Common Name: BLACK MOTTLED CRAYFISH
Scientific Name: Procambarus (Ortmannicus) enoplosternum Hobbs
Rarity Ranks: G4G5/S4
State Legal Status: None
Federal Legal Status: None
Description: This crayfish exhibits two very different color patterns. The first (shown above) has a dark carapace with cream colored splotches and a cream or orange central stripe. Beneath the dark base color it is possible to make out a darker saddle over the rear of the carapace which becomes forward pointing “horns” on the sides. The abdomen is blackish-red with lighter reddish spots on the lower sides of the abdominal segments. The claws are tan to brown with black tubercles. The alternate color pattern is much lighter with a tan or light brown carapace and abdomen; a pale central stripe on the carapace is still visible and this pattern exhibits the saddle and horns described above. In some populations of the lighter phase, the saddle is indistinct and the horns are reduced to two discrete spots. There is a single cervical spine on each side of the carapace and the rostrum is long with a distinct acumen and marginal spines or tubercles. The areola is wide. The species reaches a maximum total length of about 93 mm (3.7 in.).
Similar Species: Across its range, Black Mottled Crayfish has been collected with several other members of the genus Procambarus, including several closely related species in the subgenus Ortmannicus. It differs from White Tubercled (Procambarus spiculifer) and Ogeechee (P. petersi) crayfishes by having only one cervical spine on each side of the carapace as opposed to two on each side. Differs from White River Crawfish (P. acutus), Hummock Crayfish (P. lunzi), Eastern Red Swamp Crawfish (P. troglodytes), and Ornate Crayfish (P. howellae) by having a much wider areola. Lastly, it has occurred with Blackwater Crayfish (P. litosternum); details of the male reproductive structure will likely be required to separate these two species.
Habitat: The Black Mottled Crayfish is primarily a stream dweller but has been found in simple burrows adjacent to streams and occasionally in temporary habitats (Hobbs 1981). In streams it is usually associated with some sort of cover, particularly vegetation and undercut banks. It may also be found in leaf litter or associated with rocks or woody debris.
Diet: No studies of the Black Mottled Crayfish are known. Crayfishes are considered opportunistic omnivores and likely feed on live and decaying vegetation, aquatic insect larvae, small fishes, and dead animal matter.
Life History: Male Black Mottled Crayfish in reproductive condition have been collected in Georgia and South Carolina in all months except January and December (Hobbs 1981). Females carrying eggs were found in March, April, May, June, and July and females with young found in April, May, and August. The smallest male known is about 29 mm (1.2 in) and the smallest female with eggs is about 48 mm (1.9 in) in length (Hobbs 1981).
Survey Recommendations: Since this species is usually found in flowing water, it is most easily collected by holding a net perpendicular to the current downstream of vegetation or woody debris and kicking to dislodge and scare crayfish into the net. If there are rocks or logs in the creek, they may be carefully lifted and crayfish may be pinned by hand or coaxed into a dipnet. Using a backpack electroshocker or minnow traps can be effective as well.
Range: The species is distributed from the Little Ocmulgee River system in Georgia eastward to the Santee River basin in South Carolina (Hobbs 1981). In Georgia is most commonly found in the Ohoopee and lower Oconee river systems.
Threats: This species is apparently secure across its range.
Conservation and Management Recommendations: Conserving populations of the Black Mottled 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. Non-native crayfishes should never be used for bait; instead, anglers should use crayfishes collected from the river system where they will be fishing. Unused bait of any kind should not be released back into Georgia waters.
Hobbs, H. H., Jr. 1981. The crayfishes of Georgia. Smithsonian Contributions to Zoology 318:1-549.
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