Freshwater Mussels

Volunteer Survey Program

Scientific Studies

News and Reports

What are Freshwater Mussels?

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Freshwater mussels are bivalve mollusks just like oysters, clams, and saltwater mussels. Unlike saltwater bivalves, freshwater mussels live in our local streams and rivers. They provide valuable “ecosystem services,” or natural benefits, such as strengthening stream beds by keeping soils in place and providing food and habitat needed by other animals and plants. As filter-feeders, mussels supply another important service by cleaning the water in which they live. They suck water in and trap solids such as dirt, algae and other pollutants. Then they release the clean filtered water back into the environment. One mussel bed studied in Southeast Pennsylvania was found to remove 26 metric tons of solids from the water in a single summer season—as much as five grown elephants!

Download our guidebook to “Freshwater Mussels of the Delaware Estuary” now.

Freshwater Mussel Decline

Nearly 300 mussel species are native to North America. Over a dozen of these species were
historically found in streams throughout the Delaware Estuary. Unfortunately, few of these are commonly found in Pennsylvania, New Jersey, and Delaware today. The decline of mussels can be blamed on a combination of known and unknown factors. These factors include polluted water, toxic spills, over harvesting, loss of forests along streams, loss of fish hosts needed for reproduction and dams that block fish passage.

Freshwater Mussel Science and Recovery

Freshwater Mussel Science and Recovery

The Partnership for the Delaware Estuary recognizes the need to conserve existing mussel populations and restore native freshwater mussels to the Delaware Estuary and River Basin. PDE scientists conduct surveys to collect data on where mussels currently exist, which species are abundant, and how healthy the populations are. PDE teaches mussel workshops to train citizen scientists to help in these efforts. Scientists also assess current stream health throughout the region. If a stream is healthy and has contained mussels in the past, PDE will attempt to restore native freshwater mussels to the area by transplanting mussels from an existing nearby healthy population. PDE’s work to understand, conserve, and restore native freshwater mussels results in improvements to all-around ecosystem health—including cleaner water and better habitat for other animals in our streams and rivers.

You can learn more about our plan for freshwater mussel restoration by downloading this PDF or by contacting Dr. Danielle Kreeger or Angela Padeletti at (800) 445-4935.

Volunteer Mussel Survey Program

PDE offers one of the few programs anywhere that trains volunteers to find, identify, and report freshwater mussels, a type of water-cleaning animal. Learn more.