Neosho Mucket

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The Neosho Mucket Species Biological Report, Recovery Plan, and Recovery Implementation Strategy are now available.

To learn more about the life cycle and reproduction of mussels, click here.
For an interactive version, click here.

View the Neosho Mucket Final Critical Habitat Designation.

Neosho Mucket (Lampsilis rafinesqueana)
Status: Endangered with Critical Habitat
September 17, 2013; Critical Habitat designated April 29, 2015.

For questions regarding the Neosho Mucket, please contact Chris Davidson at chris_davidson@fws.gov or 501-513-4481.

Species Facts:
The Neosho Mucket generally reaches four to six inches in length. It is a light brown color that darkens with age, with green, discontinuous rays. It is estimated that the population has been extirpated from 60-80% of its historical range, and only one large viable population remains, located in Missouri.

The Neosho Mucket is unusual in that reproduction occurs April-May, and glochidia are released in August; other mussels in that genus breed from late summer to early winter, and release glochidia the following spring. The main host fish for the glochidia (the parasitic juvenile mussels) are smallmouth, largemouth and spotted bass. Female Neosho Muckets have specially shaped mantle flaps that look very similar to a small fish, including pigmentation that mimics an eyespot and lateral line. Muscular contractions of these flaps cause a “swimming” motion that attracts the host fish.

Habitat Summary:
The Neosho Mucket is associated with shallow riffles and runs with predominately gravel substrate and moderate to swift currents. It also occurs in backwater areas located adjacent to gravel bars. Typically individuals are deeply embedded in the substrate. This species only occurs in four river basins in Arkansas, Missouri, Kansas, and Oklahoma. In Arkansas, it is only found within the Illinois River in the northwest corner of the state.

Why is it Endangered?
Rapid urbanization and clearing of trees adjacent to the Illinois River for pastureland threaten the continued existence of this species in Arkansas. As with other freshwater mussels, the building of reservoirs and other streambed modifying activities have reduced available habitat, and water pollution is thought to have had a negative effect on the population. This was also one of the few freshwater mussel species that was harvested commercially.

The Neosho Mucket was first identified as a candidate for ESA protection in 1984. Neosho Muckets have been propagated in captivity, and some reintroduction of marked individuals has occurred.

Critical Habitat:
Critical habitat is designated when there are geographic areas containing features we believe are essential to the conservation of a species. Designation of Critical Habitat does not affect land ownership or establish a refuge, reserve, preserve, or other conservation area. It does not affect activities on the land unless they are funded by federal dollars. Learn more about critical habitat here. You can read the final critical habitat designation in the Federal Register here.

The designation of critical habitat for the Neosho mucket by the Service considers physical or biological features essential to the conservation of these species. These include, but are not limited to:

  1. Space for individual and population growth and for normal behavior;
  2. Food, water, air, light, minerals, or other nutritional or physiological requirements; and
  3. Sites for breeding, reproduction, or rearing; and

Primary constituent elements are those specific elements of the physical or biological features that provide for a species’ life history processes and are essential to the conservation of these species. Based on our current knowledge of the physical or biological features and habitat characteristics required to sustain life history processes for the Neosho mucket, the primary constituent elements specific to these species are:

  1. Primary Constituent Element 1— Geomorphically stable river channels and banks (channels that maintain lateral dimensions, longitudinal profiles, and sinuosity patterns over time without an aggrading or degrading bed elevation) with habitats that support a diversity of freshwater mussel and native fish (such as, stable riffles, sometimes with runs, and mid–channel island habitats that provide flow refuges consisting of gravel and sand substrates with low to moderate amounts of fine sediment and attached filamentous algae).
  1. Primary Constituent Element 2— A hydrologic flow regime (the severity, frequency, duration, and seasonality of discharge over time) necessary to maintain benthic habitats where the species are found and to maintain connectivity of rivers with the floodplain, allowing the exchange of nutrients and sediment for maintenance of the mussel’s and fish host’s habitat, food availability, spawning habitat for native fishes, and the ability for newly transformed juveniles to settle and become established in their habitats.

  2. Primary Constituent Element 3— Water and sediment quality (including, but not limited to, conductivity, hardness, turbidity, temperature, pH, ammonia, heavy metals, and chemical constituents) necessary to sustain natural physiological processes for normal behavior, growth, and viability of all life stages.

  3. Primary Constituent Element 4— The presence and abundance (currently unknown) of fish hosts necessary for recruitment of the Neosho mucket.  The occurrence of natural fish assemblages, reflected by fish species richness, relative abundance, and community composition, for each inhabited river or creek will serve as an indication of appropriate presence and abundance of fish hosts until appropriate host fish can be identified.    

  4. Primary Constituent Element 5— Either no competitive or predaceous invasive (nonnative) species, or such species in quantities low enough to have minimal effect on survival of freshwater mussels.

Range in Arkansas:

Arkansas Field Office
110 S. Amity Road
Suite 300
Conway, AR 72032

501/513 4470 (v)
501/513 4480 (f)

Last Updated: October 17, 2018

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