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Species Description

Crayfish

Cambarus (Hiaticambarus) longirostris


Classification

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

Description

The basic color of Cambarus longirostris is olive to orange-tan. Its carapace has two distinctive orange or tan spots. The rear portion of each segment of the abdomen is decorated with a narrow red band. The olive-colored chelae (claws) have a distinctive gap between the fingers. The areola is wide and the tail is bordered in a brown or red color. The triangular rostrum of this crayfish is small in size and lacks spines. The carapace of C. longirostris is usually 19-34 mm (0.75-1.3 in) in length.

Life Cycle

There have been relatively few life history studies conducted on crayfish. The available life history data for Cambarus longirostris 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, October and November. Egg-bearing females have been collected during late April. The life cycle of this species is presumed to be fairly similar to the generalized crayfish life history described below. Based upon the condition of specimens collected during different times of the year, C. longirostris copulation is believed to occur from October through April. 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. During the appropriate time(s) of year, 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." Each female usually carries between 94 and 182 eggs while "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. Many adult crayfish die within 3 years of hatching.

Natural History

Adult C. longirostris crayfish often hide under rocks in clear streams. This species appears to prefer the choppy, swiftest portions of streams. 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, detritus, 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 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 are sometimes found with extensive scaring on their chelae or missing appendages. This occurs while escaping predators or fighting with other crayfish. Male crayfish are especially aggressive with one another and their claw-to-claw combat can be quite intense.

Range

This species is found within portions of the Tennessee River Basin in Georgia , Tennessee , North Carolina and Virginia . Within Georgia , it is apparently limited to Lookout Creek in Dade County , Cane Creek in Walker County and Nottely River in Union County . It prefers to hide under rocks in the choppy, swift portions of these creeks and rivers.

Conservation Status

This crayfish is listed as Rare and Imperiled within Georgia . It has a very limited range within the state and is threatened by construction of impoundments and reservoirs, habitat destruction and pollution.

Similar Species

Identification of this species is particularly difficult. There are many different variations in claw size, rostrum shape and areola width. Identifying this species is usually best performed by trained individuals that can distinguish subtle differences and variations between species.