A Treasure of the Dark: Cave Crayfish

Cambarus aculabrum is a small, albino, cave-dwelling crayfish with an overall body length reaching about 3.75 inches. Like many other cave creatures, or troglobites, C. aculabrum is specially adapted to its dark surroundings, exhibiting such features as reduced eyes, lack of pigmentation, a reduced metabolic rate, delayed reproduction, and reduced egg production. This crayfish feeds on organic matter carried in by cave streams or left by other animals such as bats. Some say it can live as long as 75 years.

C. aculabrum is extremely sensitive to the quality of the water in which it lives. It is adapted to the clean, filtered water of underground streams and must have dissolved oxygen in the water for respiration. Contamination of water by sewage, animal waste, petroleum products, or any number of chemicals can deplete oxygen concentrations and suffocate the cave crayfish.

Disturbance by careless cavers can also impact the physical condition of individual cave crayfish. Since cave organisms have a low metabolic level and limited opportunities to feed, any disturbance uses up energy that could be used in feeding or reproduction. Most troglobitic species, including C. aculabrum, have a low reproductive rate and a relatively long maturity period, so illegal collection of any cave crayfish will affect the ability of the species to reproduce. All troglobitic species are protected by the Arkansas Game and Fish Commission.

C. aculabrum is presently known from only two caves in the world—Logan Cave and Bear Hollow Cave in Benton County—and is federally listed as endangered. Only a handful of cave crayfish has been observed at each site. The Conservancy is implementing conservation measures to keep the recharge area and groundwater clean for the people who drink the water and for their neighbors underneath…C. aculabrum and friends.

Species information adapted from C. aculabrum, Recovery Plan USFWS 1996.