Discover Freshwater Mussels: America's Hidden Treasure

For the Record

No other country in the world equals the United States in freshwater mussel variety. While all of Europe supports only 12 species, nearly 300 kinds live here, mostly within the vast watershed of the Mississippi River.

Unfortunately, these animals may be the most troubled natural resources in this country. It's estimated that 70% (Williams, et al. 1993) of our freshwater mussels are extinct, endangered, or in need of special protection. Many of their problems stem from how they live and changes that have occurred to their habitat during the past 200 years.

Life Down Under

Most freshwater mussels live burrowed in sand and gravel at the bottom of rivers and streams. Only a few are adapted to the quiet water and muddy depths of lakes, ponds, and reservoirs.

Unlike most animals, which must travel in search of food, their food drifts to them, mainly tiny plants and animals called plankton suspended in the water. By drawing water inside their shells through a siphon, their gills filter out food and take in oxygen.

Mussels usually don't move much, but a muscular "foot" helps them burrow and allows limited travel if disturbed by floods or drought.

The foot also helps anchor them against strong currents and may prevent a hungry muskrat from tugging them out for its dinner! A mussel's shell, however, provides its main protection from predators.

Their hard, calcium-based shells consist of two halves joined by a hinge. Unique names like "monkeyface," "threehorn wartyback," and "pink heelsplitter" refer to the wide range of shell size, color, shape, and texture found among mussel shells.

Something "Fishy"

Freshwater mussels need a lot of luck to successfully reproduce. Their unusual life cycle begins when eggs held inside the female are fertilized by sperm drawn inside her while siphoning water. For most species, if a male of her kind isn't nearby upstream, she can't reproduce. For a few, this is not a problem because they seem able to fertilize themselves.

The adaptations these species have developed to attract host fish are absolutely amazing considering mussels don't even have eyes to see what they are mimicking! When freshwater mussels "go fishing" varies by species and takes place throughout the year. However, there are several species displaying during the summer months. The wavy-rayed lampmussel is currently displaying tissue that looks like various insects and fish The rainbow mussel is displaying small black projections that look like worms. For more information about these and other species displaying this summer contact the biologists listed at the end of the article. Also, check out the Unio Gallery website link for pictures of these fascinating freshwater mussel lures.

Once fertilized, the eggs develop into a larval stage inside the female before they are released into the water to begin a parasitic stage. With little time to waste, these youngsters, called glochidia, must attach themselves to a host fish or perish. For some mussels, the host is limited to only a few fish species. This generally harmless parasitic stage lasts a matter of weeks before the larvae transform into young mussels and are ready to drop off the fish and begin a life in the stream bottom.

To increase the chances of their young making contact with a fish host, some females "go fishing." By displaying specially adapted tissues that look like fish prey, they try to lure fish to swim near them. Sensing a fish nearby, the female releases her young into the water, ready to clamp onto the fish.

Mussel Aches

Our native freshwater mussels face greater problems today than they did just a few years ago. Some problems aren't new. Although water quality has improved in some areas, pollution, especially non-point source pollution, causes the greatest threat to native mussels. Also sedimentation continues to take a serious toll. Habitat losses through channelization, clearing of riparian and streambank vegetation, dredging, and dam construction still persist. Mussels are impacted by loss of fish hosts from fish kills or dams that prevent fish migration. Poachers can impact mussles by violating harvest regulations set by conservation agencies. However, in some parts of the country, it's a non-native mussel causing the most concern.

Zebra Mussel Invasion

In 1988, the fist zebra mussels were spotted in Lake St. Claire near Lake Erie in Ohio. Assumed to have been stowaways in the ballast water of a trans-Atlantic ship, this native of eastern Europe is now widespread throughout waterways in the eastern half of the United States. Besides other problems, zebra mussels have nearly eliminated native mussels in some locations. Unlike native mussels, the much smaller zebra mussel (less than 2" in length) does not use a host animal in its life cycle, and reproduces at a tremendous rate. They can attach themselves to hard surfaces with thread-like structures called byssal threads. In zebra mussel-infested waters, it is not unusual for native mussels to be completely covered by zebra mussels. Competition for food and oxygen weakens and eventually starves native mussels.

They Lose, We Lose

Freshwater mussels have played a long and varied role in people's lives. Native Americans used them for food, tools, and jewelry. From about 1890 until the invention of plastics around 1950, mussel shells supported this country's button industry. More recently, the world's cultured pearl industry relies on implant beads made from the superior shells of North American mussels. In states where mussel collecting is legal, harvesting provides jobs and income to residents along rivers.

Mussels have other values more difficult to measure. In the rivers and lakes where they live, their filtering ability makes them natural water purifiers. They play an important role in the aquatic food chain as a food source for wildlife including muskrats and otters.

They also can tell us something about the health of the environment on which we both depend. Mussels respond to changes in water quality. Gradual mussel die-offs or sudden mussel kills are reliable indicators of water pollution problems and other environmental health concerns. Stable, diverse mussel populations generally indicate clean water and a healthy aquatic environment.

If we lose our freshwater mussels, we lose more than a biological legacy unmatched in the world. We lose a part of our cultural heritage, we lose an economic resource, and we lose an environmental health maintenance and warning system. Fortunately, there are efforts being made to avoid these losses and things everyone can do to help save our freshwater mussels.

Mussels in our Future Biologists from the U.S. Fish and Wildlife Service (Service) and the U.S. Geological Survey along with other Federal, State, and private agencies are working together to find solutions to problems facing our mussels. These partners have developed a National Strategy for the Conservation of Freshwater Mussels, which will serve as a blueprint for native mussel restoration. They have also formed the Freshwater Mollusk Conservation Society that will help guide research, restoration, and recovery efforts for freshwater mussels. Mussels and their habitats are being surveyed, monitored and restored. The Service's endangered species program is working to conserve these species and their habitat. Some mussels facing extinction in the wild have been removed and brought to the Service's National Fish Hatcheries and State facilities for safe-keeping. Hatcheries are developing techniques for propagating rare mussels for release. We are beginning to reestablish mussel populations into restored streams and rivers. The Service's Fishery Resources offices help by providing technical assistance on habitat restoration and enhancement for mussels. States manage and monitor harvest activities to ensure that populations are not depleted by use. Aquarium and zoo personnel are also assisting with conserving endangered freshwater mussels through efforts such as research and education programs. The National Wildlife Federation has a long history of working to enhance national water quality and protect endangered species through advocacy, education, and on-the-ground programs. These efforts--including the "Keep the Wild Alive" campaign, which celebrates endangered species protection efforts worldwide--are helping to improve conditions for imperiled freshwater mussels. But there's more that needs to be done and you can help. There are ways that you can help to provide a secure future for mussels. For instance, avoid contributing to water pollution. Follow application directions and don't use fertilizers and pesticides excessively. Leave stream sides vegetated even if it means giving up part of the view. Keep cattle and other livestock out of streams. Report suspected pollution problems to authorities. Get involved with land use planning in your community. In the long run, freshwater mussels will benefit from improvements in water quality. And so will you! For More Information: Photos and the Unio Gallery: Chris Barnhart Southern Missouri State University phone: 417/836-5166 e-mail: mcb095f@mail.smsu.edu Unio Gallery: http://courses.smsu.edu/mcb095f/gallery/ Additional Web Sites: USGS Biological Resources    Mussels That Matter Questions About Mussels, the Freshwater Mollusk Conservation Society, or Field Trips: Hillary Vinson - North Carolina U.S. Fish and Wildlife Service 828/258-3939 x 234 Erich Langer - Oklahoma U.S. Fish and Wildlife Service 918/581-7458 Paul Johnson Southeast Aquatic Research Institute Tennessee Aquarium pj@sari.org 706/694-4419 Steve Ahlstedt - Tennessee U.S. Geological Survey 865-545-4140 ext. 17 stever_ahlstedt@usgs.gov Hannah Hamilton - Florida U.S. Geological Survey 352-378-8181 ext.341 hannah_hamilton@usgs.gov Janet Butler Ohio River National Wildlife Refuge PO Box 1811 Parkersburg, WV 26102 304-422-0752 janet_butler@fws.gov

Conserving Native Mussels in Oklahoma - A Partnership Approach The Kiamichi - one of the most pristine and ecologically intact river basins in the region - has a watershed that drains 1, 830 square miles and is to a vast majority privately owned. Through a unique partnership that spans Federal and State agencies, local conservation and landowner organizations, and a conservation- minded corporation, the community-based Kiamichi River Initiative is a model to emulate. Historically, local landowners have done a good job protecting the river using management practices like riparian borders. The narrow watershed is heavily forested, and until recently land use was primarily limited to forestry and cattle grazing. Water uses have been limited to fishing, swimming and occasional canoeing. The free flowing river originates in the Ouachita National Forest at the Arkansas border and ends at its confluence with the Red River - the Oklahoma/Texas border. Most of the Kiamichi River basin is in narrow valleys that range from 3-12 miles in width and feature steep and rocky slopes. Pine-hardwood forest is the typical vegetation, with shortleaf pine dominating drier south-facing slopes and oaks, hickories and other hardwoods dominating north-facing slopes and bottomlands. The river is home to the Federally listed (Endangered) Ouachita rock pocketbook (Arkansia wheeleri), one of the rarest mussels in North America. This species is the world's only remaining representative of it's genus and is evolutionarily distinct and a high priority for conservation. This mussel is sensitive to long-term changes in water conditions such as temperature, nutrient levels, current, substrate, pesticides and oxygen levels. The only known healthy population of Ouachita rock pocketbooks exists in the clean waters of the Kiamichi River, home to another 28 mussel species, including seven imperiled or vulnerable ones and more than half the mussels known to live in Oklahoma waters. The species rich Kiamichi River also harbors more than 100 native fish species. Spearheaded by the Nature Conservancy's Oklahoma chapter, the Kiamichi River Initiative is based in the small southeastern Oklahoma community of Clayton and seeks to build community support for the long-term health of the Kiamichi River watershed and the communities within its borders. The Nature Conservancy recognized early on that partnerships were essential to successful program planning and decision-making and established a core team of integral Federal and state agencies and other key groups during the first months of the project. Representatives of the U.S. Forest Service, U.S. Fish and Wildlife Service, the Oklahoma Biological Survey, Ouachita Mountains Resource Conservation and Development district, Public Service Company of Oklahoma (PSO) a major electrical utility provider in the state, and The Nature Conservancy began working together. Meeting regularly, the partners provide input that helps assess the productivity and efficiency of efforts to maintain the ecological integrity of the river. Central and Southwest Services, PSO's parent company, brought needed financial capital to the partnership. The corporation contributed $80,000 to help support operational costs associated with establishing and maintaining a local office in the watershed. The Kiamichi River manager is working with local schools in the watershed. Classes will be learning about important watershed concepts and participating in hands-on water quality monitoring. To better realize the aquatic education objective, new partners from the Natural Resources Conservation Service, Oklahoma State University Extension Service and the Latimer County Conservation District have enthusiastically 'stepped to the plate.' The Nature Conservancy has assembled two 'River Resource Boxes' for area teachers. These educational trunks have stream ecology kits, field guides, books, and river activity manuals. Teachers and students can use the ecology kits to conduct aquatic sampling experiments and monitor water quality. Goals for the year 2000 include a more detailed assessment of the critical reaches of the river and the development of several private land riparian restoration projects. Cooperative projects will provide benefits to individual landowners while improving aquatic conditions on the river. Furthermore, key demonstration projects will help The Nature Conservancy show other watershed landowners the benefits of similar projects on their property. The success of the Kiamichi Initiative is entirely dependent on building local support. Initiative designers recognize that local communities must be empowered to chart a sustainable future for the Kiamichi watershed. Therefore, the development of a coalition of local citizens, landowners, community groups, corporations, Native American tribes, schools, and local, state and federal agencies is necessary. Trust in the community is slowly gaining - one individual at a time - through honest up front discussions and dialogue. Much of the ground - work for the Kiamichi Initiative involves simply listening to the desires and concerns of area landowners and residents. With continued cooperation from all partners, the ultimate goal of developing and implementing a Kiamichi River Conservation Plan will be realized. At this time, no one really knows exactly what such a document will look like. However, most participants believe that such a plan will reflect the region's desire to maintain the natural integrity of the watershed while sustaining a high quality of life for local citizens and rural landowners.

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