The shrimp crayfish is a medium-small crayfish that is light reddish brown to gray, thickly dusted with darker specks. Its rostrum (the portion of the carapace between the eyes, which projects forward) is unusually long, with the acumen (tip) longer than the base. The carapace is not separated at its middle by a space (areola). The pincers are narrow and weak. The color pattern, shape of the rostrum, and absence of an areola will distinguish this crayfish from other species within its range.
Similar species: The gray-speckled crayfish is somewhat similar in appearance, but it has heavier pincers and a shorter rostrum. Juveniles of the red swamp crayfish have a much shorter acumen.
Missouri also has two species of freshwater shrimp, which (unlike crayfish) are slender and nearly transparent. Shrimp have only the first 2 pairs of legs with pincers, whereas crayfish have pincers on the first 3 pairs of legs (the first pair being the large “lobster” claws). Also, the abdomen (“tail”) of shrimp is flattened side to side, while that of crayfish is flattened top to bottom.
Adult length: about 2 to 3 inches.
The shrimp crayfish has been collected in Missouri only from the lower St. Francis River (Dunklin County) from and Wolf Bayou (Pemiscot County).
Habitat and Conservation
An inhabitant of deep oxbow lakes and large, slow-flowing lowland rivers. It has been found in open water and among tree roots and other cover along the shore.
Food
Crayfish are generally omnivores, eating a wide variety of plant and animal materials.
Status
A species of conservation concern in Missouri. This crayfish in more common in states to our south, along the Mississippi all the way to its delta. Missouri apparently never had very much habitat suitable for the shrimp crayfish, and human-caused alterations of the environment in the Bootheel have reduced its habitat further. To keep it in our state, we must protect the Bootheel’s remaining bayous, slow-flowing lowland rivers, and deep oxbow lakes.
Life Cycle
Most of the life history information about the shrimp crayfish is from studies done in Louisiana and other states to our south. Apparently this species has a fall breeding season, and females carry eggs and young in early spring.
Human Connections
Crayfish are colorful and interesting animals. They are important members of aquatic communities, contributing to the success of anglers, froggers, and bird watchers. Missourians drained most of the swamps in the Bootheel, destroying most of the habitat for many species of plants and animals.
Ecosystem Connections
Crayfish are an important link in the food chain between plants and other animals, breaking down plant materials that are resistant to decay. They are an important food for many animals that occur around or in water, including fish, snakes, turtles, wading birds, raccoons, and mink.
