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Monitoring the effects of the operation of Yellow Creek Reservoir on the fishes of the Etowah River
Megan Hagler Institute of Ecology University of Georgia  The Etowah River is located in the Upper Coosa River basin in north Georgia. The Etowah flows approximately 165 miles (265 km) from its headwaters at the Appalachian Trail in northeast Georgia to its mouth, where it joins the Oostanaula River to form the Coosa River. The Etowah is one of the most biologically distinct rivers in the Southeastern U. S. (Abell et al. 2000; Burkhead et al. 1997). It harbors three federally protected fishes, four state protected fishes, and several additional species that are likely candidates for federal protection (see table below). The Etowah dater (Etheostoma etowahae) and amber darter (Percina antesella) are both federally endangered, and the Cherokee darter (E. scotti) is federally threatened. The Etowah and Cherokee darters are endemic to the Etowah River and the amber darter is endemic to the Upper Coosa River system. The frecklebelly madtom (Noturus sp. cf. munitus) and freckled darter (P. lenticula) are state listed. Two subspecies of the undescribed holiday darter (E. sp. cf. brevirostrum), each endemic to a sub-watershed within the Etowah basin, are currently protected by the state and are likely to be federally listed once described. The speckled chub (Macrhybopsis sp. cf. aestivalis) and bridled darter (P. sp. cf. macrocephala) are species of concern within the Etowah basin and likely warrant federal protection.
The Etowah River mainstem is bisected by Allatoona Dam and Reservoir (a U.S. Army Corps of Engineers project, completed 1950). The best remaining habitat for large-stream dwelling fishes, such as the amber and Etowah darters, occurs in the Upper Etowah River, upstream of Allatoona Reservoir. The Upper Etowah and its tributaries are under threat of losing their habitat integrity and high fish diversity from a variety of chronic anthropogenic impacts. This section of the watershed lies squarely in the path of expanding metropolitan Atlanta and is developing rapidly as a result. Several counties in this area are among the fastest growing counties in the country (e.g. Cobb and Forsyth). Urbanization and the corresponding increase in impervious surfaces negatively affects streams by altering temperature and flow regimes, decreasing groundwater recharge and base flow in streams, increasing pollutants and increasing sediment input (Arnold and Gibbons 1996; Booth 1990; Booth and Jackson 1997; Klein 1979; Paul and Meyer 2001; Wang et al. 2000). In the Etowah basin, urbanization of sub-watersheds and the resulting decline in stream habitat conditions has led to the apparent extirpation of the small-stream dwelling Cherokee darter, and declines in other darter and minnow species (Walters 2002). In urbanizing areas, water supply reservoirs are often constructed to help meet the needs of the growing human population. Impoundments inundate stream habitat, fragment fish and invertebrate populations and alter flow, temperature and chemical properties both upstream and downstream of the impoundment (Collier et al. 1996; Fagan 2002; Jackson et al. 2001). One tributary, Yellow Creek, was recently impounded and at least one more reservoir (Hickory Log Creek) has been proposed within the basin.  My research is focused on monitoring the effects of the operation of Yellow Creek Reservoir on the fishes of the Etowah River. Yellow Creek is a major tributary of the Etowah and is impounded near its mouth. The Reservoir is used for water supply; it releases water for downstream withdrawal in Canton, GA. Operation of Yellow Creek Reservoir, which began in 2002, has the potential to modify stream habitat in the Etowah River. Since 1997, Dr. Bud Freeman and his research lab at the University of Georgia (UGA), Institute of Ecology, have been monitoring ten shoals within 26 miles on Etowah River in Dawson and Cherokee Counties. Late summer to fall sampling has been conducted annually at all ten shoals (seven shoals in 1998). Five shoals upstream and five downstream of the mouth of Yellow Creek are sampled for fishes using kick-seining and seine-hauling techniques. A kick-set involves disturbing the area (about 4m2) upstream of a seine (8? x 6?, 1/8? mesh) to displace fish from hiding. Seine-hauling is used in slower velocity areas and involves pulling the seine through the water. In order to minimize the potential for mortality of listed fishes, no electrofishing equipment is used during sampling. Our sampling effort at each shoal, in terms of number of kick-sets and portion of shoal sampled, has been as similar as possible from year to year. The shoals range from 50-150m in length.
Data collected at each set/haul are maintained separately, so that each set/haul is a distinct record. A depth code and dominant substrate code are recorded for each kick-set and seine-haul. Depth is coded in three ways: less than 20cm (A); 20-50cm (B); and greater than 50cm (C). The habitat codes include four categories: (1) coarse - gravel to cobble; (2) fines - silt, sand, gravel; (3) backwater ? sand and silt; (4) boulders and bedrock. Since 2001, we have additionally measured velocity with a velocity meter at each set/haul and measured depth (in addition to the depth code). The fishes collected in each set/haul are identified, measured to standard length and released or preserved for identification and measurement in the lab (each set/haul in a different jar). Protected fishes are measured and immediately released. All preserved fishes are later accessioned into the Georgia Museum of Natural History at UGA. There are several questions that I want to address with these data. First, is there any evidence of a decline in the capture frequency of protected fishes in the study shoals? From a management perspective, most of the data collected so far are baseline data (collected before dam operation began) and could be used to interpret declines in the capture frequency of threatened and endangered species through time with regards to the operation of Yellow Creek Reservoir and also, declines in general. Secondly, is there any evidence of changes in fish community assemblage at the shoals? Recent research has shown that generalists or cosmopolitan species can replace endemic fishes in disturbed habitats (Scott et al. 2002). For this analysis I will consider changes in richness of cyprinids, percids, centrarchids, and the abundance of each T and E species between years and among sites. I will also determine if there is evidence of microhabitat preference among species by analyzing the microhabitat data recorded for each kick-set, including habitat and depth codes, and depth and velocity measurements. Little is known about most of the fishes we collect during our surveys, so this information may provide some insight into species preferences or requirements.  Finally, I am interested in how flow variability affects species, especially the young of year (yoy). Using river stage data from two sites on the Etowah within the study reach and from the mouth of Yellow Creek, I will investigate the occurrence of greater abundance or stronger year classes of a particular species in a given year. If flow affects overall species abundance and/or strength of year class, I would expect species to respond in a similar way each year across the shoals (with the exception of the shoals downstream of Yellow Creek once operation of the reservoir began). Assuming flow does have an effect on some species, are some more tolerant of drought than others (as most years of the study were drought years)? Is there any evidence that surges in spring flow (caused by storms or dam operation) has influenced the strength of the year class of those species?
Because this monitoring project is ongoing, sampling of these shoals will continue for years to come. I hope to complete my analyses thishaglerfsh3.JPG (1738819 bytes) summer and complete my thesis by December of this year. The results of my analysis will be used by those managing the protected fishes of the Etowah. Like several other rivers in Georgia, the Etowah lies entirely within our state; the future of the Etowah depends entirely on the folks that live here. Thanks to the Native Fish Conservancy for their support and to the Freeman lab, past and present. Table 1. Protected fishes of the Etowah River.
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