Crayfish, Nashville

Orconectes shoupi

phylum: Arthropoda

class: Crustacea

order: Decapoda

family: Cambaridae

status: Critically endangered, IUCN Endangered, ESA

range: USA (Tennessee)

Description and biology

The Nashville crayfish, also called the Shoup's crayfish, measures about 2 inches (5 centimeters) long. It has thickened ridges on its rostrum (snout), four pair of walking legs, and two long-fingered chelae (pronounced KEY-lee; claws or pincers). It consumes plants and animals, including algae, insects, worms, fish eggs, snails, and mussels. Raccoons, fish, and reptiles are among the main predators of this crayfish.

Biologists (people who study living organisms) know very little about the reproductive habits of the Nashville crayfish. Mating can take place from late summer to early spring. Egg laying seems to occur in early spring. Like females of other crayfish species, the female Nashville crayfish shelters her fertilized eggs by carrying them attached to her abdomen. Upon hatching, the young crayfish are fully formed, miniature versions of the adults. They cling to the mother's abdomen for several weeks after hatching before venturing out on their own.

Habitat and current distribution

This crayfish is found only in Mill and Sevenmile Creeks, tributaries of the Cumberland River near Nashville, Tennessee. In its streambed habitat, the Nashville crayfish requires adequate cover. Those crayfish in Mill Creek have been found typically in pool areas under flat slabs of limestone and other rocks.

Biologists do not know how many Nashville crayfish currently exist, although they believe the number is quite low.

History and conservation measures

Biologists have classified about 330 species of crayfish, which are also called crawfish or crawdads. Tennessee alone has more than 70 distinct species. Of the total number of crayfish species known, almost half are endangered or imperiled.

Only four crayfish species in the country have been granted federal protection by being placed on the U.S. Endangered Species List. The Nashville crayfish is one of those four listed.

In the past, the Nashville crayfish was found in three additional areas in Tennessee: Big Creek in Giles County, South Harpeth River in Davidson County, and Richland Creek in Davidson County. Biologists are unsure exactly why the crayfish disappeared from these locations, but they do know it cannot tolerate pollution and increased silt (mineral particles).

This is the threat currently facing the Nashville crayfish in its Mill Creek habitat. A constant barrage of pollutants has been flowing into the creek. Industries have built warehouses right up to the edge of the creek's banks. Nearby roads and parking lots drain into the creek. Upstream from the crayfish's habitat, pesticides and fertilizers sprayed on farmland run off into the creek.

To ensure the survival of the Nashville crayfish, conservation efforts must focus on protecting Mill Creek from further contamination.

DID YOU KNOW?

Crayfish are found on all continents on Earth except Africa and Antarctica. They are an essential part of the food chain. They feed on algae, insects, mussels, and snails, while in turn being fed on by fish, herons, otters, and other larger animals. This feeding balance has been maintained for hundreds of thousands of years. However, pollution and introduced species are currently threatening this delicate balance. The Nature Conservancy, an international nonprofit environmental organization, states in its 1997 Species Report Card: The State of U.S. Plants and Animals that crayfish and mussels are currently in the worst condition of all endangered species.