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Surgeon crayfish. Photo by Chris Lukhaup. Image may be subject to copyright.
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Faxonius forceps (Faxon, 1884)

Surgeon crayfish

Federal Protection: No US federal protection

State Protection: No Georgia state protection

Global Rank: G5

State Rank: S1

SWAP High Priority Species (SGCN): No

Element Occurrences (EOs) in Georgia: 1

Habitat Summary for element in Georgia: Prefers riffle areas under rocks in larger streams that flow over limestone deposits


Description

The overall color of the Surgeon Crayfish is light to dark brown with darker brown markings. There is a dark saddle behind the areola. The fingers of the claws are tipped orangish and are black just behind the tips. There are two rows of tubercles along the mesial margin of the palm and the fingers of the claws gape widely when they are closed. The areola is wide and shaped much like an hourglass. The rostrum is fairly long, parallel-sided, and has a long sharp acumen and marginal spines or tubercles. There is a single well developed cervical spine. The largest specimen found in Georgia is about 50 mm (2.0 in) in total length.

Similar Species

The only other species in the area that has the fingers gaping when they are closed is the Tanback Crayfish, Cambarus girardianus. The Tanback Crayfish has a striking saddled color pattern on the carapace and a broad dark stripe down the center of the abdomen. It also does not have orangish color on the tips of the fingers.

Habitat

The Surgeon Crayfish is a stream dweller and can be found beneath rocks or woody debris throughout the streams in which it inhabits. However, it is more likely to be found under rocks in riffle areas (Bouchard 1976).

Diet

No studies of the Surgeon 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. Across its range, male Surgeon Crayfish in reproductive condition have been collected in all months except December, January, February, and July. Females carrying eggs were found in March and April and one with young in April. The smallest male in reproductive condition collected is about 38 mm (1.5 in) in length (Hobbs 1981).

Survey Recommendations

Flipping larger rocks in just about any habitat in a stream should turn up this species. The animal can be pinned by hand or gently driven into a dipnet. Dipnetting through leaf packs or using a backpack electroshocker could yield specimens as well.

Range

Surgeon Crayfish is endemic to the Tennessee River system and can be found from southwestern Virginia to just west of Chattanooga, Tennessee. In Georgia, it is only known from the South Chickamauga Creek system in the northwestern portion of the state (Hobbs 1981, 1989).

Threats

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.

Georgia Conservation Status

Despite its narrow range in Georgia, the species is apparently stable.

Conservation Management Recommendations

Conserving populations of the Surgeon 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

Bouchard, R.W. 1976. Geography and ecology of crayfishes of the Cumberland Plateau and Cumberland Mountains, Kentucky, Virginia, Tennessee, Georgia and Alabama, Part I: the genera Procambarus and Orconectes. In James W. Avault, Jr., editor, Freshwater Crayfish, pages 563-584, 1 figure. Baton Rouge, Louisiana: Louisiana State 1981. University Division of Continuing Education.

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

Hobbs, H.H., Jr. 1989. An illustrated checklist of the American crayfishes (Decapoda: Astacidae, Cambaridae, and Parastacidae). Smithsonian Contributions to Zoology 480:1–236.

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, February 2019: general update of account.

D.Weiler, September 2019: photo added