The Cumberlandian combshell (Epioblasma brevidens) is a brown and yellow mussel that is about two inches (5.1 cm) long.

These mussels live in shoals and in coarse sand and boulders in medium streams to large rivers.

As they progress into adulthood, mussels become filter feeders, actively obtaining oxygen and nutrients from the water around them.

Both juvenile and adult mussels consume bacteria, algae, diatoms, some detrital, and inorganic colloidal particles.

Additionally, adult mussels often feed on phytoplankton, zooplankton, phagotrophic protozoans, and other organic material in the water.

This usually occurs between 16 and 45 days[4] During reproduction, the glochidium attaches to the gills or fins of a fish to complete its development.

Female mussels produce large numbers of larvae but few juveniles find a fish host and even fewer survive to maturity.

In the 1980s, studies placed the abundance of the combshell at around 0.01-0.03 mussels per square foot within sites in the Powell and Clinch Rivers.

Loss of genetic diversity can make a species more vulnerable to diseases, caused by bacteria, viruses, and parasites.

[4] In 2016, the Wolf Creek National Fish Hatchery successfully raised 521 Cumberlandian combshells to be released into the upper Cumberland and Licking River basins.

This number more than doubled the population of combshells believed to currently exist in the Big South Fork of the Cumberland Rivers.

[10] Scientists have also grown populations of mussels to be tagged, released, and recaptured in order to identify combshell survival rates in their natural habitat, as well as growth curves for the species.

This is because the dams permanently change the free-flowing aquatic habitat that the combshell and their fish host species require.

The Fish and Wildlife Service (FWS) have defined naturally occurring events as things such as toxic chemical spills.

Originally native to the lakes of southern Russia and Ukraine, the Zebra mussel was introduced into the rivers of North America in 1988.

Human factors, called anthropomorphic factors, that have affected the habitat include impoundments (artificially constructed water bodies), channelization (widening or deepening of river sections to increase the capacity for flow volume), water pollution and sedimentation (often due to soil runoff).

The combshell also received a 5-year review in 2005 and 2018, tracking how conservation efforts and human intervention have affected populations.

The Fish and Wildlife Services cited the decrease in range and population numbers as its reason for listing it as endangered.

[4] At the time of its listing, the Fish and Wildlife Service said that it had no plans to designate critical habitats for the combshell, but it did so in 2004.

[6] The Kentucky Department of Fish and Wildlife Resources Center for Mollusk Conservation raises combshells for release into their natural habitat.

[10] On June 25, 2019, a permit was submitted to conduct presence/absence studies of the combshell in Big South Fork National River.

[14] There is not much information about Cumberlandian combshell conservation available on the internet, though the Fish and Wildlife Services highlights several ways common citizens can help, including limiting pesticide use, planting trees to prevent soil runoff, conserving energy to prevent the construction of new hydroelectric plants and removing aquatic weeds from boat trailers and engines.