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Species Description

Crayfish

Cambarus (Hiaticambarus) fasciatus


Classification

Phylum: Arthropoda
Subphylum: Crustacea
Class: Malacostraca
Order: Decapoda
Family: Cambaridae

Description

Cambarus fasciatus has a tan to olive brown carapace with numerous dark brown markings. The antennae are pinkish cream and the tail is bluish olive with orange margins. It has a distinctive abdomen which is shorter and narrower than its carapace. Portions of the abdomen are also marked with broad dark bands. The chelae are approximately 2 times as long as they are broad and are adorned with a row of orange tubercles (small bumps). The carapace length is often between 21 and 51 mm (0.8-2.0 in). The rostrum is adorned with spines or tubercles near the margins. The areola is fairly broad and is 3 to 5 times as long as it is broad.

Life Cycle

There have been relatively few life history studies conducted on crayfish. The available life history data for Cambarus fasciatus is limited to the form or condition of specimens collected during certain times of the year. First-form (sexually mature) males have been collected from March through June. Egg-bearing females have been collected during May and June. Females collected carried between 13 and 263 eggs. The life cycle of this species is presumed to be fairly similar to the generalized crayfish life history described below. Copulation usually occurs during autumn, spring and early summer. Copulation involves a sexually mature male crayfish grabbing a female and depositing sperm packages (spermatophores) into the seminal receptacle on the abdomen of a receptive female crayfish. Usually during the spring, females secrete a sticky substance on the underside of their abdomen and pleopods in order to attach their eggs. The eggs and sperm (from the seminal receptacle) are then released upon the sticky surface and fertilization occurs. A female carrying eggs on her abdomen and legs is said to be "in berry." Embryos develop and hatch on the underside of females in 2-20 weeks, likely depending upon species and temperature. The immature hatchlings molt (shed their exoskeleton to allow growth) and remain attached to their mother. These first-stage immature crayfish look fairly similar to typical crayfish, but have disproportionately large heads and eyes. Another molting takes place in about 1-2 weeks. These second-stage immature crayfish look even more like adult crayfish. Second-stage or third-stage immature crayfish leave their mother's surface and become independent. These young crayfish continue molting and growing and are usually sexually mature by their second or third autumn. Sexually mature males and females are believed to mate between autumn and summer and many usually die within 3 years of hatching.

Natural History

Adult Cambarus fasciatus crayfish often hide under rocks or leaf litter in streams during the day. From dusk until dawn, or on very cloudy days, crayfish come out of hiding and search for food in streams. Crayfish are usually omnivorous scavengers, feeding upon whatever is available. Crayfish eat aquatic vegetation, small fish, aquatic insects and snails. They use their chelae (claws) on their first 3 legs to grab, crush and tear their food. This food is further cut by a number of specialized mouthparts. The main predators of crayfish are fish, frogs, turtles, wading birds, raccoons, otters and humans. Crayfish usually walk slowly across the bottom of their stream habitat using their last 4 walking legs (periopods). When frightened or in danger, however, they quickly escape by "darting" backwards. Crayfish sometimes have extensive scaring on their chelae or are missing appendages. This occurs while escaping predators or fighting with other crayfish. Male crayfish are particularly aggressive with one another and their claw-to-claw combat can be quite intense.

Range

Cambarus fasciatus has a limited range within the Etowah River drainage in northwestern Georgia . Its range encompasses Bartow, Cherokee, Dawson, Lumpkin, Pickens and Polk counties. It is usually found hidden beneath rocks or leaf debris in moderate to swiftly flowing streams.

Conservation Status

Cambarus fasciatus is uncommon in the state due to its limited range and is threatened by urbanization within its range. Expansion of cities could destroy its habitat or degrade the water quality of streams within its range. Its limited habitat has already been fragmented by construction of the Allatoona Lake reservoir.

Similar Species

Cambarus girardianus is the crayfish species in Georgia that looks most similar to Cambarus fasciatus. However, C. girardianus lacks broad, dark bands on its abdominal region and is limited to extreme northwestern Georgia .