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Species Description

Crayfish

Cambarus (Depressicambarus) strigosus


Classification

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

Description

Cambarus strigosus is a slender, small-eyed crayfish. The carapace is mostly olive-colored. The abdomen is olive and each segment is marked with a narrow orange band. Its tail is olive, with orange margins. The dark olive rostrum has orange margins and lacks both spines and tubercles (small bumps). The areola is very narrow or linear in appearance and has no more than one spot or pit in the narrowest portion. The chelae (claws) are adorned with a row of 5-8 tubercles. The carapace length is usually less than 36.5 mm (1.4 in) and the slender body usually measures less than 70 mm (2.8 in) in total length.

Life Cycle

There have been relatively few life history studies conducted on crayfish. The available life history data for Cambarus strigosus is limited to the form or condition of specimens collected during certain times of the year. First-form (sexually mature) males have been collected during April and October. Egg-bearing females have been collected during May. The life cycle of this species is presumed to be fairly similar to the generalized crayfish life history described below. Copulation has not been observed, but probably occurs from autumn to spring. 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 spring. Many adult crayfish die within 3 years of hatching.

Natural History

Adult Cambarus strigosus crayfish are found in complex burrows in sandy-clay soils near streams or in areas with a high water table (a water level near the surface). The burrows of this species are built in soil that is rich in organic matter. The constructed burrows often have multiple branches and at least one chamber that extends below the water table. The openings of the burrow are usually marked with chimneys (mounds of sand or mud placed around openings above ground). Occasionally it leaves the general safety of its burrow to search for food or a mate at night. Crayfish are generally omnivorous scavengers, feeding upon any food source available within their habitat. Food for this species may include plant material, insects and perhaps other crayfish. 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. Crayfish usually walk slowly using their last 4 walking legs (periopods). When frightened or in danger, however, they quickly escape by "darting" backwards into their burrows.

Range

This species has a limited range within the Broad and Little River basins. It is found within Elbert, Oglethorpe and Wilkes counties in Georgia . It builds complex burrows in sandy-clay soil near streams, ditches or in areas with a high water table.

Conservation Status

Cambarus strigosus is listed as Rare in Georgia. It has a limited range, small population size and is most threatened by habitat destruction.

Similar Species

This species of crayfish is usually distinguished by its distinct, slender body and olive and orange coloration.