Subject: Report on declines of listed and at-risk fishes from the Conasauga River
Included among them is a disturbing report on the status of several fishes endemic to the Upper Coosa Basin, and specifically population strongholds found along the Conasauga River when compared to the Etowah River.
I found this passage on page 429 particularly important for a number of reasons (both including the Conasauga, as well as the surrounding predominate land uses that may serve as warnings throughout the Southeast):
...The Conasauga and Etowah study reaches differ in
the extent and intensity of row-crop agriculture, which
flanks much of the upper Conasauga mainstem in
Georgia but is, at present, a minor land use in the upper
Etowah watershed. Several studies have reported
elevated levels of agriculturally derived nutrients and
contaminants in the Conasauga River study reach
(Sharpe and Nichols 2007; Jacobs 2013; Lasier et al.
2016). Jacobs (2013) additionally documents occurrence
of bioavailable estrogen in water and sediments of
tributaries that join the Conasauga mainstem either
upstream or in our study reach, occurrence of intersex
condition in approximately 13% of the fish collected in
these tributaries, and lowered growth in two fish
species exposed to sediment from tributaries with the
highest estrogen levels. Widespread application of
poultry litter on agricultural fields is a likely source of
steroid hormones in the Conasauga (Lasier et al. 2016).
Water and sediments in the river also have detectable
levels of the pesticide glyphosate or its breakdown
products, derived from pesticide applications to agricultural
fields along the Conasauga mainstem and
tributaries (Lasier et al. 2016).
Runoff from row-crop and animal husbandry operations
may also contribute to elevated nutrient levels in
the Conasauga River study reach. Mainstem water
samples from the study reach show occurrence of
particularly high levels of total nitrogen (e.g., .5 mg/l)
and total phosphorus (e.g., .300 ug/L; Freeman et al.
2007; Sharpe and Nichols 2007; Lasier et al. 2016). Stable
nitrogen isotope ratios of herbivorous consumers in the
Conasauga mainstem downstream from the national
forest also show evidence of nitrogen enrichment from
agricultural sources (Sharpe and Nichols 2007; Baker
2012). Other studies have found changes in fish
community structure associated with increased nutrients
(Evans-White et al. 2013; Taylor et al. 2014),
although mechanisms are unclear. However, elevated
nutrient loading may be responsible for changes in
water clarity and benthic habitats that we have
observed in the Conasauga River....
From what I have been shown by the good folks out of the GA Ecological Services Field Office, the lack of adequate field buffers clearly justify NRCS, USFWS Partnerships for Fish and Wildlife, and other agencies focusing incentives to increase extent and width of such buffers specifically along the Conasauga River.
Thanks,
Chuck
Chuck Hunter
Chief, Division of Strategic Resource Management
Regional Refuge Biologist
National Wildlife Refuge System
U.S. Fish and Wildlife Service
1875 Century Boulevard, Suite 420
Atlanta, GA 30345
404-679-7130 (office)
770-331-4475 (cell)
