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Biological Assessment |
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The overall objective of the Emory River Watershed Biological Assessment Project is to determine the current diversity and habitat condition for fish, mussels, and macroinvertebrates within the Emory River Watershed. Specific attention is being given to federally listed endangered and threatened species, including the spotfin chub (Erimonax monachus) and the purple bean mussel (Villosa perpurpurea). To help accomplish this objective, historical water quality, fish, mussel, and macroinvertebrate data have been gathered and entered into a database that is linked through a geographic information system (GIS) to assess associated land use influences.
The entire Emory River Watershed has been visited and sampling locations have been identified after consultation with the Tennessee Wildlife Resources Agency (TWRA), Tennessee Valley Authority (TVA), United States Geological Survey (USGS), Tennessee Department of Environment and Conservation (TDEC), and National Park Service (NPS) personnel. To date, 22 electrofishing sites and eight seasonal snorkeling sites have been sampled. Habitat parameters have been measured at all sites and parameters include: percent composition of habitat units (i.e., riffle, run, pool, cascade), percent composition of substrate, gradient, width, depth, water temperature, conductivity, dissolved oxygen, pH, turbidity, and flow. Additionally, at seasonal snorkel sites, lab water quality parameters (ammonia, total nitrogen, total phosphorus, and sediment) have been measured.
To assess seasonal habitat use by spotfin chubs, eight sample sites were snorkeled during Spring, Summer, and Fall 2004 (Table 1). The three sites within the Emory River (Nemo, Deermont, and Oakdale) contained more spotfin chubs than sites in the Obed River (Obed Junction), Daddy's Creek (Devil's Breakfast Table and Daddy's Junction), and Clear Creek (Lilly Bridge and Jett Bridge). Adult and young-of-the-year chubs were common in Emory River sites. Digital underwater snorkeling photos were obtained of fish. The site at Deermont had the greatest numbers of fish during summer and fall samples. The majority of spotfin chubs was found in run habitats over firm (bedrock or boulder) substrates; however, a sample from Oakdale in November 2004 found approximately 50% of fish in pools. Also, 17% of spotfin chubs observed in this sample were found over fines. These observations are the first indication that spotfin chubs in the Emory River Watershed may occupy different habitats during high-flow, low water-temperature conditions. To date, winter snorkel samples have not been possible due to high-water/high-flow conditions.
Fish communities have been sampled using electrofishing gear in Obed River and Daddy's Creek (22 sample sites, 12 within Daddy's Creek Watershed, and 10 in the Obed River Watershed, Table 2). Some samples were collected with assistance from TVA, TWRA, TDEC, and Conservation Fisheries, Inc. All fish collected were identified, enumerated, and released. To date, only three spotfin chubs have been collected through electrofishing, all from the Daddy's Junction site in the Daddy's Creek Watershed. Species richness in the Daddy's Creek Watershed varied from six species (Lick Creek and Upper Daddy's Creek sites) to 18 species (Hebbertsburg site); the Daddy's Junction site had 17 species. In the Obed River Watershed, species richness ranged from two species (Fox Creek) to 17 species (Potters Ford site). Electrofishing of Clear Creek and Emory River Watershed sites were conducted in 2005.
Benthic macroinvertebrates have been sampled from all sample sites where electrofishing has been performed, and from the eight seasonal sites during Fall 2004. Qualitative samples were obtained using a 1.0 m2 kick screen. Processing of macroinvertebrate samples has begun. Sampling will continue during 2005, with electrofishing sites in Clear Creek and Emory River, in addition to continual seasonal sampling of the eight snorkeling sites. To date, six mussel species have been observed through snorkeling, including one freshly dead purple bean mussel on the Obed River.
In addition, a newsletter documenting study progress has been developed. This newsletter, hopefully, will be available on a monthly basis to all parties involved with this project.
--Written by Brad Cook and William Russ (2005, September 11). Tennessee Technological University.
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