|Listed||October 23, 1991|
|Family||Unionidae (Freshwater Mussel)|
|Description||Medium-sized, silky textured, chestnut brown to black shell.|
|Habitat||Slow-moving side channels and pools with muddy or rocky bottoms.|
|Reproduction||Female stores sperm in gills; glochidia are released into the stream after hatching.|
|Threats||Impoundments, water pollution.|
The Ouachita rock-pocketbook is a mediumsized freshwater mussel up to 3.9 in (10 cm) long. The shell exterior is chestnut brown to black and has a silky texture. This species is also known as Arcidens wheeleri and by the alternate common name Wheeler's pearly mussel.
See the Upland Combshell (Epioblasma metastriata ) entry.
This mussel species is usually found on muddy or rocky bottoms in side channels and backwaters where there is little or no current. Freshwater mussels feed by filtering food particles from the water.
The Ouachita rock-pocketbook is known from the Kiamichi River in southeastern Oklahoma and the Little River near the Oklahoma-Arkansas border. It was first described in 1912 from specimens taken from the "Old River," at Arkadelphia, Arkansas, a reference to a series of connected oxbow lakes. The Ouachita River was mentioned as another collection site. It has been recorded in the Kiamichi River near Antlers, Tuskahoma, Clayton, and Spencerville Crossing, all in Pushmataha County. The site near Spencerville Crossing has been flooded by the Hugo Reservoir. In the Little River in Arkansas, historic collections include White Cliffs, Little River County, and at the border of Little River and Sevier Counties.
This mussel survives in the Kiamichi River in Oklahoma and the Little River in Arkansas. The Kiamichi River holds an estimated 1,000 individuals in a section of the river between the southwestern corner of LeFlore County and Antlers in Pushmataha County. Fewer than 100 individuals are estimated to survive in a 5-mi (8-km) section of the Little River that flows from the Oklahoma border between Little River and Sevier Counties, Arkansas. In all, the Ouachita rock-pocketbook occurs in low densities over an estimated range of 85 mi (137 km) of river.
The main factors in the decline of the Ouachita rock-pocketbook have been water pollution and the construction of reservoirs. The Ouachita River near Arkadelphia has been altered by a number of reservoirs and is now so polluted that it is unlikely that any mussel species could exist there. In the Little River, cold water discharges from Pine Creek Dam and pollution of the Rolling Fork Creek tributary has eliminated many mussel species. East of the 5-mi (8-km) stretch of the Little River where the mussel still occurs, the water quality is too poor to allow the Ouachita rock-pocketbook to survive.
The main threat to many Kiamichi River Ouachita rock-pocketbook populations is the planned construction of the Tuskahoma Reservoir in Pushmataha County, Oklahoma. This would flood mussel populations and affect habitat downstream. In addition, the proposed addition of hydropower to the Sardis Reservoir on Jackfork Creek, a tributary of the Kiamichi River, would disturb the current water regime, most likely stressing downstream mussels.
Along with other native mussels, the Ouachita rock-pocketbook face a threat from the introduced Asiatic clam (Corbicula fluminea ). This introduced species now occurs in Hugo Reservoir and is slowly moving upstream.
Conservation and Recovery
The Ouachita rock-pocketbook is listed as an endangered species by the U.S. FIsh and Wildlife Service and by the IUCN. Conservation of this rare mollusk requires that its only known critical habitats be protected in reaches of the Little River, the Ouachita River, and the Kiamichi River upstream from Hugo Reservoir. The most important potential threats are associated with the reservoir development, but pollution by siltation and chemicals are also factors that must be controlled. The endangered mussel must also be strictly protected from any collecting. Little is known about the life history and habitat requirements of the Ouachita rock-pocket-book, so research is needed into these areas. Field surveys should continue to be made for additional populations, and the known ones and their habitat conditions should be monitored.
U. S. Fish and Wildlife Service
Regional Office, Division of Endangered Species
1875 Century Blvd., Suite 200
Atlanta, Georgia 30345
U. S. Fish and Wildlife Service
Oklahoma Ecological Services Field Office
222 South Houston, Suite A
Tulsa, Oklahoma 74127
Telephone: (918) 581-7458
Fax: (918) 581-7467
Harris, J. L., and M. E. Gordon. 1987. Distribution and Status of Rare and Endangered Mussels (Mollusca: Margaritiferidae, Unionidae) in Arkansas. Arkansas Game and Fish Commission, Little Rock.
Mehlhop-Cifelli, P., and E. K. Miller. 1989. "Status and Distribution of Arkansia wheeleri Ortmann & Walker, 1912 (Syn. Arcidens wheeleri) in the Kiamichi River, Oklahoma." U. S. Fish and Wildlife Service, Tulsa, Okla.