Monroe County, Arkansas

Note: This information is provided for reference purposes only. Although the information provided here was accurate and current when first created, it is now outdated.

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The fat pocketbook pearly mussel is of the North American family Unionidae. A far larger percentage of this family are imperiled than any other species group. This mussel is about 4 inches long and has a smooth, shiny yellow to brown outer shell that is iridescent bluish white on the inside. It is found in sand, mud, or gravel in streams and rivers less than 8 feet deep, and feeds by siphoning phytoplankton and other plant matter from the water.

Historically, the fat pocketbook was found in portions of the Wabash, Mississippi, Ohio, and Illinois River. It now is believed to be found in a small, undredged portion of the St. Francis River in St. Francis County County, Arkansas. Few specimens were found in the mid-1970's in the Wabash River in Posey County, Indiana and a small tributary in Pike County, Indiana but is uncertain whether the fat pocketbook populations in these areas are still viable and reproducing.

Major factors affecting these mussel populations are alterations in temperature, waterflow, and siltation caused by stream damming, channeling, and dredging. Agricultural runoffs and industrial practices have also affected the mussel habitat by degrading water quality. Because mussels are filter feeders, the effects of pollution are intensified due to the large quantities of water drawn through their siphons in the feeding process.

Efforts to restore fat pocketbook populations include transplatation attempts by the Army Corps of Engineers, habitat reconstruction sites by the Fish and Wildlife Service, and concerted efforts by individuals and industries to ensure water quality.

Matthews, J.R. (ed.), The Official World Wildlife Fund Guide to Endangered Species, Beacham Publishing Inc, Washington, DC. Vol II, pp. 1009-1010.

The pink mucket pearly mussel has an elliptical shell that is 4 in. long, 2.4 in. wide, and 3 inches high. Young mussels have a yellow to brown shell that is smooth and glossy with green rays and growthmarks, while older specimens are a dull brown. This mussel is a unique long-term breeder in which male pink muckets release sperm in late summer or fall that fertilizes larvae in females which is incubated until the following spring. The pink mucket pearly mussel inhabits shallow riffles or shoals in areas of gravel, rubble, or sand substrates that have been swept free of silt by the current. (Silt clogs the siphons in which mussels use to strain water for nutrients.)

In the past, populations of this mussel were found in 25 rivers and tributaries in 11 states. Currently, the pink mucket is known in 16 rivers and tributaries from 7 states with the greatest concentrations in the Tennessee (TN, AL) and Cumberland (TN, KY) rivers, and in the Osage and Meramec rivers (MO). However, large numbers of this species have never been collected and it has always been considered rare. Smaller populations have been found in the Clinch River (TN), Green River (KY), Kwanawha River (WV), in the Big River, Black and Little Black, Gasconde rivers (MO), and in Current and Spring rivers (AR).

The pink mucket has declined in range and numbers due to dam and reservoir construction that has changed natural river flow, water temperatures, and oxygen and sediment contents. In addition, heavy loads of silt from strip mining, coal washing, dredging, and logging, along with agricultural runoffs have significantly deteriorated water quality essential for mussel reproduction and feeding.

In attempts to restore pink mucket habitat, the states of Tennessee and Alabama have designated mussel sanctuaries in parts of the Cumberland and Tennessee Rivers and have sucessfully reproduced populations at these locations. Recently, live specimens were discovered in the upper Ohio River where the pink mucket had not been found for 75 years. Scientists associate this to improved water quality in the area and believe that this species could be similarly reintroduced to areas in which the pink mucket has been extirpated if water quality is restored.

Matthews, J.R. (ed.), The Official World Wildlife Fund Guide to Endangered Species, Beacham Publishing Inc, Washington, DC. Vol. II, pp. 985-986.