Davis Branch in Cumberland Gap National Historical Park was considered important for the recovery of the Federally threatened Chrosomus cumberlandensis (Blackside Dace). Monitoring of the Davis Branch population began in 1990. Castor canadensis (North American Beaver) colonization was reported in 1994, and a series of dams have persisted in the upper section of the stream. The pervasive effects of Beavers on Blackside Dace populations were unknown. Our goals were: 1) to characterize the fish community structure and relative abundance of Blackside Dace within the assemblage, 2) to determine the direct and indirect effects of beaver dams on the fish community, and Blackside Dace population, 3) to monitor the age structure of the Blackside Dace population, and 4) to recommend management actions that will enhance the Blackside Dace population within Davis Branch. Fishes were collected from eight stations annually from 1990–2010, except for 2003–2005. Stations were delineated within downstream and upstream sections based on Beaver presence, and within three periods, prior (1990–1993), post (1994–2002), and recent (2006–2010). Fish community structure indicated distinct downstream and upstream assemblages prior to Beaver colonization, with the relative abundance of Blackside Dace approximately 6% and 18%, respectively. The fish assemblage and relative abundance of Blackside Dace shifted over time, with the relative abundance of Lepomis gulosus (Warmouth), Lepomis auritus (Redbreast Sunfish), and Chrosomus erythrogaster (Southern Redbelly Dace) increasing, and Blackside Dace decreasing; only 25 Blackside Dace were encountered from 2006–2010. Comparison of Blackside Dace age classes between the 3 periods indicated the 0 age class decreased over time and 1 and 2 age classes increased initially but eventually declined within both the downstream and upstream sections. It is speculated that the continued presence of beaver dams increased stream temperatures downstream and upstream, altered the flow regime, and changed the available habitat, thus creating conditions more suitable for centrarchid species and Southern Redbelly Dace, which probably preyed upon and out-competed Blackside Dace, respectively. It is recommended that the National Park Service and its partners 1) develop a Beaver management program, 2) return Davis Branch to its free-flowing, pre-Beaver condition, 3) significantly decrease nonnative species and decrease native centrarchid species to abundances prior to Beaver colonization, and 4) establish a Davis Branch Blackside Dace propagation and reintroduction program.

The US Fish and Wildlife Service has focused the majority of its Blackside Dace recovery efforts on preservation of extant populations, discovery of unknown populations, and delineation of unoccupied suitable habitats. A missing component of its recovery program has been a large-scale habitat improvement project for the species. Between 2006 and 2010, we evaluated the change in Blackside Dace abundance and distribution in response to a 739-m restoration project on Mill Branch, a second-order tributary of Stinking Creek in Knox County, KY We expected Blackside Dace abundance to increase post-restoration and predicted the species would expand its distribution within Mill Branch to include downstream reaches. The improved habitat conditions were expected to lead to increased diversity and abundance of other fishes. Fish surveys produced a total of 14,580 individuals, representing 29 species. For the overall fish community, mean (± SD) species richness in restored reaches (reach la; 21 ±1, and reach 2a; 11.3 ±0.58) was significantly greater than mean species richness in unrestored reaches 1 (12.3 ± 3.1) and 2 (7.3 ± 1.53). Reach 2a also had significantly greater diversity (1.7 ± 0.17) and evenness (0.69 ± 0.07) than reach 2 (1.05 ± 0.19 and 0.53 ± 0.04, respectively). Catch per unit of effort (CPUE) did not differ significantly between restored and unrestored reaches. Blackside Dace abundance ranged from a low of 76 in February 2006 (pre-restoration) to a high of 566 in October 2009 (postrestoration). No significant increase in Blackside Dace CPUE or abundance was detected within restored reaches. Our expectations with regard to Blackside Dace abundance and CPUE were not met, but we contend that the species has benefited from the restoration. The species’ movement within Mill Branch is no longer restricted by a perched culvert at the Walker Road crossing, the reach downstream of Walker Road no longer has intermittent flow, and the entire 739-m project area is protected from significant habitat disturbance. Unfortunately, predatory centrarchids such as Redbreast Sunfish have increased post-restoration and may be limiting Blackside Dace recovery. Nonetheless, we expect the Blackside Dace population to increase within Mill Branch as the restoration matures and habitat conditions continue to stabilize and improve.

Integrated modeling frameworks allow resource managers to incorporate multiple sources of information (both data and expert judgment), acknowledge uncertainty, and make quantitative predictions about resource outcomes. To demonstrate the utility of an integrated-modeling approach for recovery planning of imperiled species, we developed a comprehensive model in the form of a Bayesian-belief network to support recovery of a federally listed stream fish, Chrosomus cumberlandensis (Blackside Dace). Our model quantitatively combined expert judgment and data from empirical studies to create a comprehensive model that is testable, transferable, and easily communicated. Sensitivity- and scenario-building analyses demonstrated that mining impacts such as elevated stream conductivity were the most influential variables affecting predicted local Blackside Dace population persistence. Our results suggest that mining impacts are a logical focal point for research and recovery actions for the species, but additional review and revision of the model are recommended. Taken as a whole, our effort enhances the current and future capacity for informed recovery-management of Blackside Dace populations.

Chrosomus cumberlandensis (Blackside Dace) is a federally protected stream fish endemic to the upper Cumberland River drainage of Kentucky and Tennessee. Captive propagation of the species has been conducted in only one previous study. Here we report new findings from spawning and rearing the species for the past three years, 2011–2013, at the Conservation Fisheries, Inc. (CFI) facility in Knoxville, TN. Brood stock (n = 80 adults) were collected in 2011–2012 from Big Lick Branch in Pulaski County, KY Spawning at the CFI facility occurred in April and May of each year when CFI water temperatures were between 16 and 21 °C. We compare CFI spawning dates and temperatures to those measured in a 2006 field study. We also provide video footage of spawning behavior, which conformed to that previously described in the literature. Per capita production of fry (i.e., number of juveniles reared per breeding adult) in 2012 was more than twice that achieved in the previous study. We progressively reduced the presence of (and cues from) other fish species in 2011, 2012, and 2013, with the eventual achievement of having Blackside Dace spawn completely independent from any heterospecific cues. Our results collectively increase the capacity to propagate Blackside Dace in captivity to support ongoing recovery efforts for this threatened species.

We report new occurrence records of Blackside Dace, Chrosomus cumberlandensis, from the Big South Fork (BSF) Cumberland River drainage in Kentucky and Tennessee. The species was not previously known to occur in the BSF basin. Our new records are from 4 streams in McCreary County, KY, and 4 streams in Scott County, TN. These records represent a downstream extension of the species' known range in the Cumberland River system, as well as a geographic range expansion to the west and south.

In 1995, personnel from the Tennessee Valley Authority discovered a population of a Chrosomus sp. in the North Fork Powell River system in Lee County, VA. Subsequent survey work revealed the species to be Chrosomus cumberlandensis (Blackside Dace). Since 1999, approximately 90 sites targeting the genus have been surveyed in the upper Powell and Clinch River systems of Lee and Scott counties, VA and Hancock and Hawkins counties, TN. Chrosomus cumberlandensis was found in two creek systems in the North Fork Powell River system and a single creek system in the Upper Clinch River system. Distribution patterns and previous genetics work suggests these populations are introduced.

Chrosomus cumberlandensis (Blackside Dace) is a small-bodied, freshwater fish endemic to the upper Cumberland River system in southeastern Kentucky and northeastern Tennessee. A detailed study of its habitat requirements using presence-absence data has not been published to date. Identification of important habitat variables at multiple spatial scales would facilitate proactive management and recovery of this federally listed species. Using logistic regression, we developed and validated habitat models of Blackside Dace presence as a function of environmental variables measured at two spatial scales (i.e., stream and reach). For model development, map-produced and field-collected variables were gathered for 91 waterways at the stream scale and 72 localities at the 200-m reach scale during summer. Our initial models predicted the likelihood of Blackside Dace presence to be optimized in streams with crude gradient between 1% and 6%, and in reaches with a turbidity ≤10 NTU, dissolved oxygen >8.5 mg/L, summer water temperatures between 14.6 °C and 18.5 °C, conductivity <240 µS, percent riffle between 35% and 50%, and link magnitude between 3 and 6, although the species was occasionally observed in locations with conditions outside of this predicted optimal range. We then validated the models by collecting additional data from 27 new streams and 47 new reaches. Model performance was assessed with Cohen's kappa (κ;). The strongest models included conductivity as a predictor variable, with the combination of conductivity and temperature producing the strongest performance (κ; = 0.41). Models containing crude gradient, turbidity, dissolved oxygen, and percent riffle generally did not perform well upon validation. Our findings suggest that conductivity, water temperature, and link magnitude are three important reach-scale variables for resource managers to consider when conserving populations of Blackside Dace.

Chrosomus cumberlandensis (Blackside Dace) is a federally protected cyprinid fish found in small tributaries of the upper Cumberland River system in southeastern Kentucky and northeastern Tennessee. Relatively little is known about the species’ reproductive ecology and early life history. From a small number of field observations, the species is known to spawn as an associate with other cyprinid nest-building hosts, namely Campostoma anomalum (Central Stoneroller) and Semotilus atromaculatus (Creek Chub). In the present study, we first analyzed Blackside Dace co-occurrence patterns with other cyprinids to predict the relative importance of each species to Blackside Dace nestassociation behavior. We next studied Blackside Dace spawning activities in seven 200-m reaches in five Kentucky streams during May-July 2006 to document nest associations and measure microhabitat conditions at spawning and non-spawning locations. Three of the seven study reaches were impacted by active logging operations. We observed 25 Blackside Dace spawning events, and all 25 were associated with Creek Chub nests, consistent with predictions from our species co-occurrence analysis. Spawning microhabitats were located in areas with significantly greater mean wetted-channel widths, slower column and bottom velocities, lower silt levels, lower substrate embeddedness, and larger subdominant substrate particles compared to non-spawning microhabitats. Study reaches with adjacent active logging had significantly greater mean silt levels, substrate embeddedness, water temperature, and conductivity values compared to reaches with no active logging, although 4 of the 25 spawning events occurred in reaches with active logging. Our results highlight the importance of cyprinid nest-building hosts (especially Creek Chub) to Blackside Dace reproductive ecology, and they also reinforce the need to maintain the integrity of Blackside Dace streams at the whole-community level.

Chrosomus cumberlandensis (Blackside Dace) is a rare cyprinid fish restricted to small tributaries in the upper Cumberland River drainage in southeastern Kentucky and northeastern Tennessee. One hundred and nineteen 200-m reaches within 55 streams were sampled during June–August 2003, 2005, and 2006 via AC and pulsed-DC singlepass backpack electrofishing, thereby representing the most comprehensive quantitative survey conducted for this species to date. Dace were found to inhabit 43 of 55 streams and 78 of 119 reaches, although in two-thirds of the reaches the species was either not detected or was present in low numbers (i.e., catch rates ≤10 dace per 200 m). For the 78 reaches where the dace was detected, single-pass electrofishing catch rates ranged from 1 to 151 (mean ± SD = 27 ± 34) dace per 200 m. Petersen mark-recapture population estimates conducted on 16 reaches within 12 streams were used to build a regression model to calibrate single-pass electrofishing catch for the remaining 62 reaches inhabited by dace. Population estimates for the 78 reaches harboring Blackside Dace averaged 90 ± 121 dace per 200 m, and associated densities averaged 14.1 ± 19.4 dace per 100 m². Electrofishing sampling efficiency for Blackside Dace was 0.30 as revealed through our mark-recapture efforts. The small population sizes documented in many streams coupled with restricted distributions and relatively limited mobility may render many populations susceptible to local extinction due to stochastic events, poor recruitment, or additional habitat degradation.

Chrosomus cumberlandensis (Blackside Dace) is a threatened stream fish endemic to the upper Cumberland River drainage in Kentucky and Tennessee. Little is known about the movement patterns of this species. Acquiring an understanding of baseline dispersal patterns is necessary to inform management and recovery actions. We tagged 653 Blackside Dace with visible implant elastomer injections in the Big Lick Branch and Rock Creek watersheds of southeastern Kentucky to determine the frequency, spatial extent, directionality, and environmental correlates of dace movements. We recaptured dace from February 2003 through March 2004 using baited minnow traps. Most tagged dace (81% in Big Lick Branch and 58% in Rock Creek) were recaptured within the same 200-m stream reach where tagging occurred. However, several individuals moved considerable distances from the original tagging site, including the first documented intertributary movement for this species. Mean (± SD) distances moved upstream in Big Lick Branch (148 ± 138 m) and Rock Creek (733 ± 1259 m) were not significantly different from mean distances moved downstream (77 ± 29 m and 314 ± 617 m, respectively). However, the mean overall distance moved was greater in Rock Creek, a longer stream than Big Lick Branch. The spatial arrangement of traps in both watersheds likely produced a distance-weighted bias such that we slightly overestimated the frequency of short-distance movements and underestimated the frequency of long-distance movements. Our results for Blackside Dace are consistent with a number of other studies that found stream fish populations composed of a large sedentary group and a smaller mobile group. The demonstrated ability of Blackside Dace to move into and between tributaries will remain vital for long-term population viability, and emphasizes the importance of maintaining suitable corridors within and among Cumberland River tributary streams.

From 2003 to 2012, we surveyed the fishes of Lick Fork, a Blackside Dace (Chrosomus cumberlandensis) stream in Bell County, KY The downstream half of Lick Fork flows through a subdivision, where it is interrupted by a perched culvert that restricts the movement of fishes within Lick Fork. The fish faunas and abundance of Blackside Dace upstream and downstream of the culvert were strikingly different. Downstream of the culvert, the fish fauna was species-rich (9–13 species), KIBI scores were high (48–56, considered “Good” to “Excellent”), and Blackside Dace were common. In contrast, upstream of the culvert Blackside Dace were rare, only two species—Semotilus atromaculatus (Creek Chub) and Rhinichthys atratulus (Blacknose Dace)—were found in abundance, and KIBI scores were lower (33–48, considered “Fair” to “Good”). Comparison with historical collections (1994) revealed declines or extirpations of some fishes (Chrosomus and Etheostoma) upstream of the culvert. The striking difference in the upstream and downstream faunas and the decline of some fish species, including Blackside Dace, is likely due to upstream extirpations from droughts or other stochastic events, coupled with the inability to recolonize from downstream populations because of the culvert barrier. This conclusion suggests that bridge and culvert design and placement are important considerations in management of Blackside Dace streams, as they can have a significant effect on community composition and fish movement.

Fracking fluids were released into Acorn Fork, KY, a designated Outstanding State Resource Water, and habitat for the threatened Chrosomus cumberlandensis (Blackside Dace). As a result, stream pH dropped to 5.6 and stream conductivity increased to 35,000 µS/cm, and aquatic invertebrates and fish were killed or distressed. The objective of this study was to describe post-fracking water quality in Acorn Fork and evaluate if the changes in water quality could have extirpated Blackside Dace populations. Semotilus atromaculatus (Creek Chub) and Lepomis cyanellus (Green Sunfish) were collected from Acorn Fork a month after fracking in lieu of unavailable Blackside Dace. Tissues were histologically analyzed for indicators of stress and percent of fish with lesions. Fish exposed to affected Acorn Fork waters showed general signs of stress and had a higher incidence of gill lesions than unexposed reference fish. Gill lesions observed were consistent with exposure to low pH and toxic concentrations of heavy metals. Gill uptake of aluminum and iron was demonstrated at sites with correspondingly high concentrations of these metals. The abrupt and persistent changes in post-fracking water quality resulted in toxic conditions that could have been deleterious to Blackside Dace health and survival.