Presentation on theme: "Tennessees freshwater mussels by Steve Henegar. Nearly 300 species in North America Most diverse populations of mussels on earth 130 species in Tennessee."— Presentation transcript:
Tennessees freshwater mussels by Steve Henegar
Nearly 300 species in North America Most diverse populations of mussels on earth 130 species in Tennessee (second only to Alabama) 49 species in Clinch River 38 or more species in Nolichucky River
Only 12 species in all of Europe Only 7 species west of Rocky Mountains
Mussels are good indicators of clean water Constantly filter water Especially sensitive to pollution Spend their entire adult life in one place Long lived Importance
TWRA (1) a two- valved shell (2) a soft body (3) a muscular foot Morphology
Life History The life cycle of a mussel is quite complex. Fertilized eggs develop into larvae, called glochidia, within the gills of female mussels. Glochidia, when released from the female may come in contact with a passing fish and although harmless to their host attach to the gills, fins or body of that fish. After a few days to several weeks, the glochidia free themselves from the host, drift to the bottom substrate and begin their lives as juvenile mussels. It may take several (2-9) years before juveniles mature and can reproduce as an adult. Adults may live 60 to 70 years if conditions are right. TWRA
Ptychobranchu s subtentum (fluted kidneyshell) from the Clinch River, collected by Jim Layzer. This individual released over 200 ovisacs. The ovisacs of fluted kidneyshell re semble aquatic insects. Each ovisac is roughly 2 cm long, of which about 2/3 is "tail".
Commercial Use The shells of native Tennessee mussels are ideal for the lucrative cultured pearl industry 80 percent of the mussel shells exported from the United States are harvested in Tennessee Currently, two to five million pounds of mussel shells with a wholesale value of two to six million dollars are harvested annually. TWRA
Freshwater Mussels One of the most endangered groups of animals on earth It's estimated that 70% (Williams, et al. 1993) of our freshwater mussels are extinct, endangered, or in need of special protection.
Freshwater mussels in TN rivers, elsewhere need protection, U.S. says 9:52 AM, Jan. 19, 2011 | Written by The daily news journal January 19, 2011 www.tennessean.com Filed Under News News Nashville Area The U.S. Fish and Wildlife Service has proposed Endangered Species Act protection for the sheepnose and the spectaclecase, two freshwater mussels found in river systems in the eastern half of the United States. Threats to both the sheepnose and the spectaclecase include loss and degradation of stream and river habitat due to impoundments, channelization, chemical contaminants, mining and sedimentation. Freshwater mussels require clean water; their decline often signals a decline in the water quality of the streams and rivers they inhabit. The Services proposal, published Wednesday in the Federal Register, initiates a public comment period during which the Service will gather information on the two mussels. The Service will make a final decision on whether to extend Endangered Species Act protection to the sheepnose and spectaclecase after evaluating all available information. If the two mussels are listed under the Endangered Species Act, the Service will work cooperatively with partners to conserve their habitats. Sheepnose are currently found in Alabama, Illinois, Indiana, Iowa, Kentucky, Minnesota, Mississippi, Missouri, Ohio, Pennsylvania, Tennessee, Virginia, West Virginia, and Wisconsin. The sheepnose occurs in 24 streams, down from 77, a 69 percent decline. Very few of these populations are known to be reproducing. In Tennessee, the mussel is found in the Hoston, Clinch, Powell rivers in the eastern part of the state and in the Cumberland, Obey and Caney Fork rivers in the middle part. The spectaclecase once occurred in at least 44 streams but now occurs in 19 streams, a 57 percent reduction in the number of occupied streams. Of the 19 remaining populations, six are represented by only one or two known specimens each. Spectaclecase mussels are currently found in Alabama, Arkansas, Illinois, Iowa, Kentucky, Minnesota, Missouri, Tennessee, Virginia, West Virginia, and Wisconsin. The species is found in the Nolichucky and Clinch rivers in East Tennessee and Cumberland, Duck and Caney Fork rivers in the midstate.
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. Zebra Mussel Invasion USFWS
U.S. Geological Survey Dreissena polymorpha Pallas, 1769 Common name: zebra mussel
zebra mussel in Tennessee occurred on the Tennessee River at Savannah, Hardin Co., Tennessee during February 1992 Tennessee River up to Knoxville and the Cumberland River above Nashville on Old Hickory Dam zebra mussels below Watts Bar Dam, at TRM527.1, increased from 600 to just over 5,000 per square meter in late 2001 At TRM558.2, zebra mussels reached an even higher density of 23,166 per square meter unknown factors caused the population to dramatically decline Only two live zebra mussels were encountered at nine TWRA freshwater mussel assessment sites below Watts Bar Dam during sampling conducted in 2005 Some native mussels collected from the Mississippi River have been covered with zebra mussels. TWRA
For many years Ive quietly done my share Ive worked endlessly without a care. For all of this I dont expect very much Only a safe place to live and such. Ill continue to make the world a better place Just keep me employed in my tiny space. A friend of mine has written this plea For I could not, I am disappearing silently..
Tennessees freshwater mussels are quietly disappearing.