U.S. Fish & Wildlife Service Purple Bean perpurpurea

An amazing diversity of life inhabits live over 150 years, the purple bean is a the free-flowing rivers of the eastern relatively short-lived and may United States. Colorful crayfish, only live up to 20 years. dazzling fish and fascinating pearly mussels are among the many aquatic Hitching a Ride that inhabit our rivers. It is The reproduction cycle of freshwater easy to overlook the animals living mussels is unique and begins when the in our streams, but they are part males release sperm into the water. of a healthy aquatic ecosystem and Relying on the current, the females indicators of clean water. One such filter the sperm out of the water during USFWS is the purple bean mussel, feeding and respiration. The filtered Purple bean named for its small bean-like shape sperm fertilize the mussel eggs, which Humans and Mussels and beautiful purple nacre (inside develop into larvae called glochidia. Mussels have long been important to surface of the shell). Historically, One female may produce thousands of people. For some Native Americans, the purple bean was never widely glochidia. The tiny glochidia are stored mussels were an important food distributed and populations were in brooding chambers within the gills source. Today, huge middens (old piles known to exist in only a few rivers and of the female mussels to await a host of mussel shells) can be found along streams in the upper Tennessee River fish. Purple bean females have adapted rivers marking regular areas where watershed in northeast Tennessee special behaviors and tissue that are Native Americas shucked mussels. and southwest Virginia. Today, used to lure the host fish to them. Native Americans and early settlers these populations are either gone or Gravid (pregnant) females will partially also used mussel shells as tools for disappearing. The species was listed as protrude their glochidia-filled gills scooping and cutting. Later, Americans a federally endangered species in 1997. outside their shells and wave finger- used mussel shells to make buttons. like papillae around the exposed gills. Until the development of plastic in the Life on the Bottom This behavior makes the gills look like early 1900s, the button industry was Purple bean mussels live in waters potential food and attracts the attention enormous, and provided an important ranging from small headwater streams of small riffle-dwelling fish, namely the U.S. export worldwide. Today, some to medium-sized rivers. Just 1½ to 2 fantail darter (Etheostoma flabellare), freshwater mussel species are used inches long, they are typically found greenside darter (Etheostoma in the freshwater and cultured pearl in moderate to fast flowing riffles, blennioides), black sculpin (Cottus industry, though the purple bean is too snuggled on the river bottom in a mix baileyi), mottled sculpin (Cottus small to be harvested for this purpose. of sand, gravel and cobbles. To survive, bairdi), and banded sculpin (Cottus purple beans need a silt-free, stable carolinae). The host fish is lured into As the canary in the coal mine is an streambed and well-oxygenated water biting the gills of the mussel, which indicator of healthy air, the presence free of pollutants. Like fish, mussels results in a mouthful of glochidia that or absence of the purple bean mussel use gills to breathe but unlike fish, attach to the fish’s gills. While there, indicates the health of an aquatic mussels are filter feeders and use their the glochidia find the nourishment ecosystem. Mussels continually siphon gills to collect food. Small hairs (cilia) and shelter they need to transform water from their surroundings; since cover their gills and beat in a rhythmic into free-living juvenile mussels. After they are relatively immobile, they motion. This motion creates a current a few weeks, the newly developed accumulate chemicals in their bodies that flows over the surface of the gills, mussels drop off the fish into the river and shells, including contaminants enabling the mussels to remove oxygen bottom and the cycle continues; the present in their environment. Not and food (bacteria and algae) from the fish generally are unharmed. This only is the presence or absence of water. Mussels have a soft muscular sophisticated reproductive strategy freshwater mussels an indication of “foot” that enables them to slowly depends on healthy fish populations a stream’s health, mussels can also crawl and burrow in the river bottom. of specific fish species that serve as be analyzed by scientists to identify Most mussels will remain in the same host fish and as “taxicabs” to carry the contaminants and toxins that may be in area of the stream for their entire life. juvenile mussels throughout the river, the water. If the water is too polluted Though some species of mussels can expanding the mussel’s range. for mussels, it is also bad for people. Trouble in Mussel Paradise Because mussels move very little in their lifetime, they are not able to escape changes in their environment that may harm them. loss and alteration are the primary reasons for the purple bean’s decline. These habitat changes result from impoundment of waterways, stream channelization, water pollution and siltation. Silt from erosion and poor land-use practices changes the stream habitat and clogs the mussels’ gills, smothering them. Dam construction and other impoundments alter many aspects of a river – speed (velocity), temperature, oxygen levels, the amount and placement of silt, and changes in water levels. Additionally, dams become a barrier to host fish and mussels, Help! Be Part of the Solution preventing them from occupying Remember that what we put on the habitat upstream. Pollutants from land eventually enters our streams. If chemical spills, agricultural runoff, you reside on property that borders coal mining and development build up a stream or other waterway, please in the mussels’ tissues and prevent minimize use of chemicals or fertilizers. them from reproducing, or kill them To help control erosion and reduce outright. Degraded habitat and poor runoff, maintain a buffer of native water quality also impact the diversity vegetation along stream banks. and abundance of fish species that the Install fencing to prevent livestock purple bean relies on for its life cycle. from entering streams; livestock can The invasive, non-native, Asian clam trample mussels, cause soil erosion, and (Corbicula fluminea) occupies valuable contaminate water with their waste. space in freshwater mussel habitat, Protecting water quality is the most though the level this threat poses to the effective way to keep our waterways purple bean is not fully known. healthy for the benefit of humans, and purple bean mussels. Saving the Purple Bean Biologists fear that the decline of To find out more about the purple bean freshwater mussels is a sign of serious contact: water quality problems in freshwater U.S. Fish and Wildlife Service ecosystems. Mussels perform many Southwestern Virginia Field Office essential functions. They are a food 330 Cummings Street source for otters, raccoons, muskrats, Abingdon, Virginia 24210 turtles and some fish. Mussels improve 276/623 1233 water quality by filtering particles and excess nutrients from the water. Federal Relay Service The U.S. Fish and Wildlife Service for the deaf and hard-of-hearing has written a recovery plan for the 1 800/877 8339 purple bean, a document that outlines what and where priority research and U.S. Fish & Wildlife Service restoration projects must be done 1 800/344 WILD to recover the purple bean mussel. http://www.fws.gov Conservation efforts for the purple bean include breeding the mussel in October 2010 captivity and reintroducing young mussels to streams, fencing streams to keep out livestock, repairing erosion along rivers, and helping local communities learn about the natural treasures that live in their streams.