Washington County, Virginia
Note: This information is provided for reference purposes only. Although the information provided here was accurate and current when first created, it is now outdated.
Pesticide Table for Freshwater Mollusks | Pesticide Table for the Spotfin Chub
About Freshwater Mollusks | About the Spotfin Chub
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Pesticide Table for Freswater Mollusks
Limitations on Pesticide Use
|1||Do not apply this pesticide within 20 yards of the water's edge within the shaded area for ground applications nor within 100 yards for aerial applications.|
|2||Do not apply this pesticide within 40 yards of the water's edge within the shaded area for ground applications nor within 200 yards for aerial applications.|
|20||Do not apply directly to water within the shaded area.|
|40||Do not apply this pesticide to cattle within 100 yards of the water's edge within the shaded area. Do not allow treated cattle to enter the water in such a way that fenthion could wash off their backs and sides, for 100 days after treatment.|
|41||Do not apply this pesticide within 1/4 mile of the water's edge within the shaded area for ground applications , nor within 1/2 mile for aerial applications.|
|43||Do not apply this pesticide within 100 yards of the water's edge within the shaded area for ground applications , nor within 1/4 mile for aerial applications.|
Pesticide Table for the Spotfin Chub
*TAR = Threshold Application Rate (Pounds of Active Ingredient per acre per application )
|1||Do not apply this pesticide within 20 yards of the water's edge within the the shaded area for ground applications, nor within 100 yards for aerial applications.|
|20||Do not apply directly to water within the shaded area.|
|41||Do not apply this pesticide within 1/4 mile of the edge of water within the shaded area for ground applications , nor within 1/2 mile for aerial applications.|
|43||Do not apply this pesticide within 100 yards of the edge of water within the shaded area for ground applications , nor within 1/4 mile for aerial applications.|
|199||Do not apply this pesticide above the threshold application rate (TAR) indicated within 20 yards of the water's edge within the shaded area for ground applications nor within 100 yards for aerial applications.|
Freshwater mussel [Unionidae]
Among the Freshwater mollusks found in this area is the Tan riffle shell. This mussels is in the family Unionidae, a family restricted to North America. A far larger percentage of this family are imperiled than any other taxonomic (species) group. Freshwater mussels can live up to 50 years. In the parasitic larval stage of the mollusk lifecycle it is dependant on fish within its habitat for nutrients and mobility. However, only a few host fish are known. Mature mussels bury themselves in the riffles and shoals and feed by siphoning phytoplankton and other plant matter from the water. Reverse siphoning is used to expell undigestible particles from the shell. Silt in the water can kill mussels by clogging their feeding siphons.
Major factors affecting mussel populations are alterations in temperature, waterflow, and siltation caused by stream damming and channeling. Agricultural runoffs and industrial practices have also affected the mussel habitat by degrading water quality and causing siltation. Because mussels are filter feeders, the effects of pollution are intensified due to the large quantities of water drawn through their siphons in the feeding process. Another significant threat to this species is the widespread and rapid population growth of the introduced zebra mussel. The zebra mussel not only competes with native species, but also attatches to them, adding so much weight that the native species cannot open to feed. In the past, commerial harvests contributed to the decline of freshwater mussels but this industry has since been reduced.
Matthews, J.R. (ed.), The Official World Wildlife Fund Guide to Endangered Species, Beacham Publishing Inc, Washington, DC. Vol II, pp. 955-956.
Spotfin chub [Hybopsis monacha]
The spotfin chub is a small, slender fish, not exceeding 4 inches in length. Juveniles, females, and nonbreeding males have tan-, gray-, or olive-colored backs, bright silvery sides, and white bellies. A dark spot is sometimes visible at the base of the tail. Large breeding males have olive or tan backs, brilliant iridescent turquiose or royal blue on the upper sides of their bodies, and midsides and bellies that are silvery cream. Their fins are a satiny turquiose and sometimes have a gold glint.
The spotfin chub spawns from mid-May to early September. Females deposit eggs in crevices between rocks that males fertilize the eggs by repeatedly swimming over. Spotfin habitat is in clear water over gravel, boulders, and bedrock in large creeks and medium-sized rivers having moderate current. The spotfin feeds on tiny insect larvae that occur on the stream bottom.
The spotfin chub is known historically from twelve Tennessee tributaries in Virginia, Tennessee, North Carolina, Georgia, and Alabama. However, much of the species' habitat has been destroyed or seriously altered. Most of the Tennessee River and many of its tributaries are now impounded. Forested watersheds have been cleared, and many streams are choked with silt. Other streams are polluted by domestic, agricultural, mining, and industrial wastes. As a rusult of this habitat loss, the species now survives in only four isolated tributary systems-the Buffalo River, Lewis County, Tennessee; Emory River (including the Obed River, Clear Creek, and Daddys Creek), Morgan, Cumberland, and Fentess Counties, Tennessee; North Fork Holston River, Hawkins and Sullivan Counties, Tennessee, and Scott and Washington Counties, Virginia; and Little Tennessee River, Macon and Swain Counties, North Carolina.
Some streams have begun to improve, and spotfin recovery efforts are underway. During the past few falls, adult spotfin chubs have been collected from the Little Tennessee River in North Carolina. These fish have been released into Abrams Creek in the Great Smokey Mountains National Park, Bount County, Tenneessee, in an attempt to reestablish one of the lost populations. Other streams are being considered for possible reintroductions.
Matthews, J.R. (ed.), The Official World Wildlife Fund Guide to Endangered Species, Beacham Publishing Inc, Washington, DC. Vol II, pp. 887-888.