Description and Distribution of Species Covered by the Etowah HCP

Description and Distribution of Species Covered by the Etowah HCP
Byron J. Freeman, Georgia Museum of Natural History
Seth J. Wenger, UGA River Basin Center
November, 2006
This document provides a brief summary of the three federally listed fish species covered by the
Etowah HCP (the Etowah darter, amber darter and Cherokee darter), as well as six other
imperiled species that will benefit from the Etowah HCP: the Coosa chub, the Coosa madtom,
the holiday darter (two species), the freckled darter and the bridled darter. Several of these
species have not yet been formally described, and for many species details of diet, reproduction
and other habits are poorly known. Nevertheless, we have endeavored to assemble the best
available scientific information on each species. Range maps are provided for each species,
based on collection data maintained by the Georgia Museum of Natural History.
Coosa Chub (Macryhybopsis sp. cf. M. aestivalis “B”)
The speckled chub (Macryhybopsis aestivalis) Gilbert is a species complex (i.e., it is currently
considered a single species but is expected to be subdivided into separate species) with a
distribution ranging from Florida to New Mexico and from southern Texas to Minnesota
(Boschung and Mayden 2004). These silvery minnows are generally characterized by the
presence of barbels and scattered dark spots over the body. Recent morphological and genetic
analyses support the division of the complex into multiple independent species, including one
occupying the upper Coosa River system (Boschung and Mayden 2004). Populations of this
“Coosa” chub are found throughout the upper Etowah River mainstem above Canton, Georgia,
occurring primarily in deeper gravel riffles and runs (Figure 3). It is limited to the river proper
and the lowest reaches of major tributaries and is not found in smaller streams. Other
populations of the Coosa chub are found in rivers above the Fall Line in the Cahaba, Tallapoosa
and Conasauga drainages (Boschung and Mayden 2004).
The life history of the Coosa chub has not been studied, although most aspects are presumably
similar to those of others in the speckled chub complex, as described in Boschung and Mayden
(2004). The speckled chub is a known omnivore consuming plant material, insects and
crustaceans. It spawns from mid-May to late August, depositing eggs in deep water; the eggs
develop as they drift downstream. Individuals are relatively short lived with an estimated life
expectancy of one to two years. The Coosa chub is listed as endangered in Georgia pursuant to
the state Endangered Wildlife Act (EWA) but is not listed under the ESA.
Figure 3. Presumed range and known collections of the Coosa chub in the Etowah Basin.
Coosa madtom (Noturus sp. cf. N. munitus)
While not yet described, the Coosa madtom is a recently-recognized, distinct entity formerly
synonymous with the frecklebelly madtom (Noturus munitus Suttkus and Taylor; Boschung and
Mayden 2004). The Coosa madtom is limited to the mainstems of the Etowah and Conasauga
Rivers (Figure 4 shows the range within the Etowah Basin). Little is known of the life history of
the Coosa madtom or other members of the frecklebelly madtom species complex although all
inhabit shoals and feed on aquatic invertebrates (Miller 1984). The Coosa madtom is often
found in association with riverweed (Podostemum ceratophyllum; Boschung and Mayden 2004,
Hagler 2006). Based on the habits of closely related species, it is presumed that the Coosa
madtom spawns in late spring and summer, with the females depositing eggs in cavities and the
males guarding the nests until after the young have emerged (Boschung and Mayden 2004,
Etnier and Starnes 1993).
Neither the Coosa madtom nor the frecklebelly madtom have federal status under the ESA,
although Boschung and Mayden (2004) and Warren et al. (2000) recommend “threatened” status
for the frecklebelly madtom. It is state-listed as endangered in Georgia. The isolated
populations of the Coosa madtom and its apparent need for free flowing, clean and unimpounded
stretches of river make the species vulnerable to extirpation through in-stream alterations and
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off-stream development. Sedimentation, river and stream impoundment and chemical pollution
will likely affect the viability of this narrowly distributed species.
Figure 4. Presumed range and known collections of the Coosa madtom in the Etowah Basin.
Holiday darter (Etheostoma sp. cf. E. brevirostrum A and B)
The holiday darter is a recently described (Suttkus and Etnier 1991) percid fish and a member of
the subgenus Ulocentra, the snubnose darters. The holiday darter is found in five separate
populations: Shoal Creek in northeastern Alabama, the upper Conasauga, the Coosawattee,
Amicalola Creek in the upper Etowah and the Etowah headwaters. Recent studies have found
differences in spawning coloration among males from different populations, suggesting that the
holiday darter represents a complex rather than a single species (Noel Burkhead, pers. com., and
pers. obs.) It is thought that the holiday darter populations known from Amicalola Creek and the
Etowah headwaters are genetically distinct from one another and from the other three
populations (Noel Burkhead, pers. com.). We treat them here as two species, holiday darter “A”
occupying Amicalola Creek and holiday darter “B” occupying the Etowah headwaters (Figure
5).
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All holiday darter species typically inhabit medium-sized, high-gradient streams. Individuals are
commonly found in swift currents near cobbles and boulders or near stream margins amongst
gravel, cobble and sand. The species is known to spawn in the spring with females attaching
single eggs to cobble and boulders (Suttkus and Etnier 1991). As with other snubnose darters,
the males exhibit brilliant nuptial coloration before and during the spawning season. It is
presumed that the diet of the holiday darter is similar to that of other members of the subgenus
Ulocentra, with midge and black fly larvae comprising the majority of items consumed
(Boschung and Mayden 2004, Etnier and Starnes 1993).
Limited to the headwaters of the upper Coosa tributaries and isolated from one another, all
members of the holiday darter complex are highly susceptible to extirpation. The holiday darter
is listed as endangered pursuant to the Georgia EWA but is currently not listed under the ESA.
Figure 5. Presumed range and known collections of the holiday darter in the Etowah Basin.
Etowah darter (Etheostoma etowahae Wood and Mayden)
Another recently described percid fish (Wood and Mayden 1993), the Etowah darter is formerly
synonymous with the greenbreast darter, Etheostoma jordani. The Etowah darter is endemic to
the Etowah River system and is found in the Etowah River upstream of Allatoona Reservoir and
in larger tributaries (Figure 6). Recent genetic analyses of populations of greenbreast darters
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have shown additional populations of Etowah darters in the Stamp Creek system and
downstream of Allatoona Dam in the Raccoon Creek system (Brady Porter, pers. com.). The
Etowah darter is listed as endangered by the ESA and the state EWA.
The preferred habitat of the Etowah darter is swift runs and riffles over cobble, gravel and
boulder substrates (Wood and Mayden 1993). Based on studies of the closely related
greenbreast darter, the Etowah darter’s diet is presumed to consist of aquatic invertebrates. The
spawning season is presumed to be similar to that of the greenbreast darter, whose season
extends from April through June when water temperatures range from 18-29ºC (Orr and Ramsey
1990).
While the greenbreast darter is often collected in large numbers where found, the Etowah darter
is often represented by only one or very few individuals. Significant numbers have only been
found in a few localities, including the Etowah headwaters, Shoal Creek (Dawson County),
Amicalola Creek, Long Swamp Creek and Raccoon Creek.
Figure 6. Presumed range and known collections of the Etowah darter in the Etowah Basin.
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Cherokee darter (Etheostoma scotti Bauer, Etnier and Burkhead)
The Cherokee darter is a member of the subgenus Ulocentra, along with the holiday darter
described above. Originally synonymous with the Coosa darter (Etheostoma coosae), the
Cherokee darter was recognized as a distinct species in 1995 (Bauer et al. 1995). In that same
year the Cherokee darter was listed as a threatened species under the ESA. The Georgia EWA
lists it as endangered. Its entire range is confined to the Etowah basin, from Raccoon Creek
(downstream extent) to Camp Creek and unnamed tributaries of the Etowah River near
Dahlonega, Georgia (upstream extent; Figure 7). It most commonly inhabits small streams and
creeks although it is occasionally collected in larger streams and is known from one locality in
the Etowah River proper.
A recent life history study on the Cherokee darter has found that its spawning season extends
from mid- March to mid-June (Storey et al. 2006). Cherokee darters deposit single eggs in small
depressions or recesses on the surface of large gravel, small cobble and occasionally woody
debris within runs, moderate to slow riffles and the tails of pools. The male pursues the female
and attempts to fertilize each egg as it is deposited. Deposition sites are typically free of fine
sediment or algal growth, but females have also been observed to clean prospective deposition
points with the mouth (Storey et al. 2006). While an analysis of diet was not included in the life
history study, Cherokee darters presumably prey upon midge and black fly larvae and other
small aquatic invertebrates.
Recent genetic analyses support recognition of three genetic Evolutionary Significant Units
(ESUs) across the range of the Cherokee darter (Storey 2003). These ESUs are supported by
mitochondrial DNA genetic distances among populations and in part by color variations among
nuptial males. The ESUs have been labeled Upper, Middle and Lower in correspondence to their
geographic location within the Etowah River basin (Figure 8). The Lower ESU encompasses all
waters supporting Cherokee darters below Allatoona Dam as well as Stamp Creek and the
tributaries entering into Allatoona Reservoir within the Allatoona Creek arm of that reservoir.
The Middle ESU includes populations from the Little River system and Sweetwater Creek
(downstream extent) and includes all major tributaries containing Cherokee darters continuing
upstream to Amicalola Creek. The Upper ESU includes populations contained within all major
systems upstream from Amicalola Creek to the furthest upstream extent of the species. The
genetic analysis has also uncovered an additional population of Cherokee darters from the Pettit
Creek system in Bartow County (Storey 2003). This population falls within the Lower ESU and
is evidently sympatric with Coosa darters (Etheostoma coosae).
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Figure 7. Presumed range and known collections of the Cherokee darter in the Etowah Basin.
Figure 8. Cherokee darter evolutionarily significant units.
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Amber darter (Percina antesella Williams and Etnier)
The amber darter is a percid fish endemic to the Conasauga and Etowah Rivers. It has an
extremely limited distribution within major tributaries of the Etowah River and in shoals of the
Etowah River upstream of Canton, Georgia (Figure 9). The only Etowah tributaries known to
harbor or to have harbored the amber darter are Shoal and Sharp Mountain Creeks in the central
Etowah River basin. The amber darter is also known from a 55 km reach of the Conasauga
River, where it is rare.
Amber darters are found in swift flowing riffles and runs with depths ranging from 0.2m to over
0.6m, often in association with moveable gravel, cobble and riverweed (Freeman 1983, Freeman
and Freeman 1994). This species is rarely if ever collected in slow velocities or over/amongst
substrate other than gravel. Individuals have been observed to bury themselves in gravel, and
females are known to bury their eggs in these sediments during spawning (pers. obs.). Spawning
occurs in late winter and spring. It is presumed that newly hatched larvae drift after hatching and
occupy slower velocity habitat until development is complete. The lifespan of an amber darter is
estimated at three to four years. Its diet is known to include snails, limpets and aquatic insect
larvae (Freeman 1983).
The amber darter is listed as endangered pursuant to the state EWA and the ESA.
Figure 9. Presumed range and known collections of the amber darter in the Etowah Basin.
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Freckled darter (Percina lenticula Richards and Knapp)
The freckled darter is the largest of all darters, reaching an estimated maximum size of 20 cm in
total length (Page 1983). The freckled darter is listed as an endangered species under the
Georgia EWA but is not listed federally. The freckled darter has a disjunct distribution ranging
from the Pearl and Pascagoula Rivers in Mississippi, to the lower Tallapoosa, Cahaba,
Tombigbee, and Alabama Rivers in Alabama, and the Etowah and Conasauga Rivers in Georgia.
In Georgia, the populations of the freckled darter are limited to the upper Conasauga and upper
Etowah Rivers (Figure 10 shows the distribution within the Etowah Basin). The freckled darter
in Georgia is typically collected in swift, deep water and is often found in association with large
woody debris. Freckled darters are also collected in proximity to cobbles, boulders, bedrock,
water willow and riverweed.
The freckled darter is infrequently collected and considered rare across its range (Boschung and
Mayden 2004). Due to the difficulty in sampling its preferred habitat, the population size of the
species is not easily determined. Likewise, the life history of the species is understudied due to
the difficulty of making observations in the deep and fast water preferred by the species.
Information regarding spawning, diet or habitat utilization is based on specimens examined.
Results of such studies suggest that the freckled darter spawns in early spring and its diet is
composed of large aquatic insects (Rakocinski 1991).
Figure 10. Presumed range and known collections of the freckled darter in the Etowah Basin.
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Bridled darter (Percina sp. cf. P. macrocephala)
The bridled darter is an undescribed member of a species complex that also includes the
Muscadine bridled darter (Percina sp. cf. P. macrocephala “B”) and the Warrior bridled darter
(Percina sp. cf. P. macrocephala “A”). Based on records at the Georgia Museum of Natural
History, the species that occurs in the Etowah also occurs in the Conasauga and Coosawattee
systems. It is listed as endangered under the state EWA but is not federally listed, although
Etnier and Starnes (1993) recommend threatened status.
While some life history aspects have been studied for the Muscadine bridled darter, little is
known of the bridled darter of the upper Coosa. The Muscadine darter occurs in a wide range of
stream sizes while the bridled darter of the upper Coosa system is typically found in mediumsized streams to small rivers. The Muscadine darter is known to spawn from late March to July
in swift-flowing runs over cobble and gravel (Wieland and Ramsey 1987). In contrast to many
other darters, the members of the species complex feed in the water column as well as the
benthos (Wieland and Ramsey 1987). Unlike the Muscadine darter, which is widespread and
relatively common in the Tallapoosa drainage, the bridled darter is rarely found consistently or in
any sizeable numbers wherever it is collected in the upper Coosa. The known occurrences of the
bridled darter in the Etowah River system are from Long Swamp Creek in Pickens County, upper
Amicalola Creek in Dawson County, lower Nimblewill Creek in Lumpkin County, and the
Etowah River in Dawson and Lumpkin counties (Figure 11).
Figure 11. Presumed range and known collections of the bridled darter in the Etowah Basin.
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References
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(Osteichthyes: Percidae), a new darter from the Etowah River system in Georgia. Bulletin
of the Alabama Museum of Natural History 17: 1-16.
Boschung, H. T., Jr., and R. L. Mayden. 2004. Fishes of Alabama. Smithsonian Institution,
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Etnier, D. A., and W. C. Starnes. 1993. The Fishes of Tennessee. The University of Tennessee
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Freeman, B. J. 1983. Final Report on the Status of Etheostoma trisella, the Trispot Darter, and
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