Ecological flow needs of freshwater mussels

Science Center Objects

Streamflow characteristics are rapidly changing in response to climate variability, water management practices, and a variety of other human water demands.  Alterations in water quantity can have direct impacts on aquatic organisms (e.g., stranding, displacement, disruption of spawning), and can be especially detrimental to organisms with limited mobility.  Freshwater mussels are one such group of organisms.  Within the United States, ~30% of the U.S.’s 300 freshwater mussel species are listed as threatened or endangered.  Mussels are considered to be ecosystem engineers due to their profound impacts on stream quality and function, impacting nutrient dynamics, primary production, and community composition of co-occurring aquatic species.  Resource managers in many locations are seeking to minimize dramatic alterations to streamflow to conserve numerous key aquatic species, while still meeting the many water demands of humans. 

USGS researchers are working to identify the streamflow characteristics (e.g. depth, flow, temperature) that are most important for sustaining freshwater mussel populations and their host fish.  Much of this work has focused on the Federally endangered dwarf wedgemussel, Alasmidonta heterodon, a rare species found in several major waterways along the Atlantic Coast.  However, researchers have also been addressing the ecological flow requirements of both at risk and common mussel species given their importance to streams and rivers and an increased interest in conserving and restoring native populations to improve water quality. 

Related Articles:

Dwarf wedgemussel, Alasmidonta heterodon

The dwarf wedgemussel is a federally listed species found along the Atlantic Coast of the U.S.  USGS researchers have identified and surveyed new populations and are working to determine the habitat needs of this rare species. 

(Credit: Jeffrey Cole, USGS Leetown Science Center. Public domain.)

Freshwater mussel physiology

USGS researchers are measuring the physiological processes occurring in freshwater mussels (e.g. metabolic rate, feeding rate) as a way of determining the range of optimal habitat conditions for each species. 

(Credit: Carrie Blakeslee, USGS Leetown Science Center. Public domain.)

Freshwater Mussels

Laboratory studies investigating the critical thermal maximum of the creeper, Strophitus undulatus, in response to varying acclimation temperatures.

(Credit: Heather Galbraith, USGS LSC. Public domain.)

Surveying for dwarf wedgemussels

Understanding ecological flow needs requires an evaluation of species distribution and field habitat conditions.  USGS researchers conduct various types of surveys to locate new populations, monitor existing populations, and quantify habitat.  Here, researchers are conducting quantitative quadrat surveys for freshwater mussels to estimate the number of individuals that are found both above and buried below the stream bottom. 

(Credit: Barbara White, USGS Leetown Science Center. Public domain.)