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Cambarus manningi Hobbs, 1981

Greensaddle crayfish

Federal Protection: No US federal protection

State Protection: No Georgia state protection

Global Rank: G4

State Rank: S1?

SWAP High Priority Species (SGCN): Yes

Element Occurrences (EOs) in Georgia: 5

Habitat Summary for element in Georgia: Rocky riffles in streams with moderate to swift current


Description

This is a strikingly colored crayfish with bases of all legs and the tail fan light blue. The carapace is greenish to brown and has a dark saddle behind the areola. The edges of the rostrum are bright orange to red and the rear edge of each abdominal segment is bright red. The abdominal segments are greenish-blue to bluish-black. The claws are dark greenish to light brown. There is a single row of nearly indistinguishable tubercles along the mesial margin of the palm and there is gap between the fingers of the claws when the fingers are closed. There is usually a tuft of hair-like setae at the base of the fixed finger of the claw. The areola is wide and the rostrum tapers and does not have marginal spines or tubercles. This species reaches a maximum total body length of about 57 mm (2.2 in).

Similar Species

In Georgia, no other species occurs with Greensaddle Crayfish that has a large gap between the fingers of the claw when the fingers are closed.

Habitat

The Greensaddle Crayfish is a stream dweller that lives among rocks in the fast moving areas of streams.

Diet

No studies of the Greensaddle 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

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 Greensaddle Crayfish in reproductive condition have been collected in May, September, and October. A single female with eggs was collected in May. The smallest breeding male known is about 35 mm (1.4 in) and the only female with eggs is about 42 mm (1.7 in) in length (Hobbs 1981).

Survey Recommendations

Since this species is usually found in swiftly 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 may also be effective. Baited minnow traps set overnight may work as well.

Range

The Greensaddle Crayfish is known from the upper Coosa River system in Alabama, Georgia, and Tennessee. In Georgia it has been collected in the Conasauga River proper, Coahulla Creek, the Armuchee Creek system, and the Big Cedar Creek system (Hobbs 1981).

Threats

The primary threat facing Greensaddle Crayfish, and other stream dwelling species, is the introduction of non-native invasive crayfish species.

Georgia Conservation Status

This species is uncommonly encountered but not considered imperiled at this time by the State of Georgia nor Alabama or Tennessee.

Conservation Management Recommendations

Conserving populations of the Greensaddle 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.

References

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 32:372–389.

Authors of Account

Christopher E. Skelton

Date Compiled or Updated

C. Skelton, 2012: original account

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