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Cambarus speciosus Hobbs, 1981

Beautiful Crayfish

Federal Protection: No US federal protection

State Protection: Endangered

Global Rank: G2

State Rank: S2

SWAP High Priority Species (SGCN): Yes

Element Occurrences (EOs) in Georgia: 17

Habitat Summary for element in Georgia: Medium-sized streams with clear water and moderate to swift current with rock-littered substrate


Description

The carapace color of the Beautiful Crayfish is orange-tan and the abdomen greenish. There are greenish bands in front and behind the areola creating a moderate saddled appearance. The edges of the rostrum and rear margins of the abdominal segments are reddish. The areola is wide with margins nearly parallel sided and a well developed cervical spine is present on each side of the carapace. The rostrum is narrow and tapers anteriorly. The claws can be quite large in relation to the body and there is a gap between the fingers of the claw when the fingers are closed. There is usually a tuft of setae at the base of the fixed finger of the claw. This species reaches a maximum total body length of about 90 mm (3.5 in).

Similar Species

The Beautiful Crayfish differs from all other species within its range, except the Coosawattee Crayfish (Cambarus coosawattae), by having claws with a large gap between the fingers when the fingers are closed. It differs from the Coosawattee Crayfish by having a single, well developed cervical spine and a gradually tapering rostrum rather than a rostrum that appears “pinched” in the middle.

Habitat

The Beautiful Crayfish is usually collected in medium-sized streams from beneath rocks in moderate to swift current.

Diet

No studies of the Beautiful Crayfish 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.

Life History

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. Male Beautiful Crayfish in reproductive condition have been collected in April, September, and October and a single female carrying eggs was found in April. The smallest reproductive male is about 56 mm (2.2 in) and the female with eggs is about 61 mm (2.4 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 a large rock, then lifting the rock and disturbing the substrate beneath it. If a crayfish is hiding underneath the rock, it will likely move into the net. Shocking downstream into a seine net with a backpack electroshocker is also effective. Collections in spring or fall are more likely to produce males in reproductive condition, which can be helpful with identifications.

Range

The Beautiful Crayfish is endemic to the Coosawattee River system (Upper Coosa River system) in northwestern Georgia. Records are known from Talking Rock Creek and several other streams and rivers upstream of Carter’s Lake Reservoir. Almost all of the occupied watersheds fall within the Blue Ridge physiographic province. Hobbs (1981) reported it from 10 locations and Schuster (2001) documented it at five additional sites. Skelton (2016) reported it from a total of 22 sites.

Threats

The small range of this species and the high development rates within that range are significant threats to the Beautiful Crayfish. With more development comes an increase in impervious surfaces. This can lead to more frequent and severe stormwater flows that carry toxins and increase water temperatures; these threats are harmful to all aquatic life. Heavy sedimentation resulting from poor development and land management practices may cover substrates and other daytime hiding places on which crayfishes rely to avoid predation. The introduction of non-native crayfishes is a threat to all native crayfishes. Since this species is adapted to flowing water habitats, reservoir development in the Coosawattee River drainage would eliminate populations upstream of any new dams.

Georgia Conservation Status

Populations at collection locations were apparently secure during status surveys conducted in 2001 and 2013.

Conservation Management Recommendations

Conserving populations of the Beautiful 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 they will be fishing in and should never release unused bait crayfish back into Georgia waters.

References

Hobbs, H.H., Jr. 1981. The crayfishes of Georgia. Smithsonian Contributions to Zoology 318:1–549.

Schuster, G.A. 2001. A study of the current status of two species of crayfishes, Cambarus coosawattae, and Cambarus speciosus, both endemic to the Coosawattee River system, in northern Georgia. Final Report. Georgia Forest Watch, Ellijay, GA. 9 pp.

Skelton, C.E. 2016. Status Assessment for 14 Crayfish Petitioned for Listing. Final Report. United States Fish and Wildlife Service, Athens, GA. 71 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.

Authors of Account

Christopher E. Skelton

Date Compiled or Updated

C. Skelton, 2008: original account

C. Skelton, January 2019: general update of account.

Photo by Georgia DNR – Wildlife Resources