Chipola Slabshell

Elliptio chipolaensis

Description

The Elliptio chipolaensis (Chipola slabshell) is a medium-sized species reaching a length of about 3.3 in (8.5 cm). The shell is ovate to subelliptical, somewhat inflated and with the posterior ridge starting out rounded, but flattening to form a prominent biangulate margin. The surface is smooth and chestnut colored. Dark brown coloration may appear in the umbonal region and the remaining surface may exhibit alternating light and dark bands. The umbos are prominent, well above the hingeline. Internally, the umbonal cavity is rather deep. The lateral teeth are long, slender, and slightly curved; two in the left and one in the right valve. The pseudocardinal teeth are compressed and crenulate; two in the left and one in the right valve. Nacre color is salmon, becoming more intense dorsally and somewhat iri-descent posteriorly.

Behavior

The host fish for the Chipola slabshell is unknown at this time. Centrarchids (the sunfish family) have been determined to be fish hosts for species of Elliptio, and may also serve as host for the Chipola slabshell. Minnows (Cyprinidae) may serve as hosts for this species. The larvae are parasitic on fish; adults are filter-feeders. The reproduction process involves the female siphoning sperm from the water to achieve fertilization of the eggs, which hatch into parasitic larvae, which metamorphose into sedentary adults.

Habitat

The Chipola slabshell occurs in warm temperate rivers and creeks. It occurs in softer-sediment habitats.

Distribution

The Chipola slabshell is only known from sites in the Chattahoochee River system, and a small tributary of the Chattahoochee River in extreme southeast Alabama.

Threats

The Chipola slabshell occurred historically at eight sites in the Chipola River and one site in the Chattahoochee River system. However, it is now extirpated from the Chattahoochee River system, and much reduced in the Chipola River system. The most recent status survey in the mid-1990s found this species only at five of 33 sites sampled within its historic range. An average of only 3.7 live individuals were found per site, and there was no evidence of recruitment into the population.

Conservation and Recovery

The Chipola slabshell is only surviving in small populations in a fraction of its historical range. It must be strictly protected from any harvesting. Its critical habitat must be protected from damage caused by new impoundments or dredging. Its surviving populations should be monitored and research undertaken into its biology (including the host species of its larvae) and habitat needs. Consideration should be given to establishing additional populations by transplanation.

Contacts

U.S. Fish and Wildlife Service
Jacksonville Ecological Services Field Office
6620 Southpoint Drive South, Suite 310
Jacksonville, Florida 32216
Telephone: (904) 232-2580

U. S. Fish and Wildlife Service
Regional Office, Division of Endangered Species
1875 Century Blvd., Suite 200
Atlanta, Georgia 30345
http://southeast.fws.gov/

Reference

U.S. Fish and Wildlife Service. 16 March 1998. "Endangered and Threatened Wildlife and Plants; Determination of Endangered Status for Five Freshwater Mussels and Threatened Status for Two Freshwater Mussels From the Eastern Gulf Slope Drainages of Alabama, Florida, and Georgia." Federal Register 63(50):12664-12687.