Prepared in cooperation with the U.S. Army Corps of Engineers, Wilmington District

Monitoring of Endangered Roanoke Logperch 

(Percina rex) in Smith River Upstream from the 

Philpott Reservoir on U.S. Army Corps of Engineers 

Property near Martinsville, Virginia

Open-File Report 2012–1221

U.S. Department of the Interior

U.S. Geological Survey
Cover photograph. Smith River near White Falls, Virginia (photograph by James Roberts, Department of 

Fish and Wildlife Conservation).
Monitoring of Endangered Roanoke 

Logperch (Percina rex) in Smith River 

Upstream from the Philpott Reservoir on 

U.S. Army Corps of Engineers Property near 

Martinsville, Virginia

By James H. Roberts and Paul L. Angermeier

Prepared in cooperation with the U.S. Army Corps of Engineers, Wilmington District

Open-File Report 2012–1221

U.S. Department of the Interior

U.S. Geological Survey
U.S. Department of the Interior

KEN SALAZAR, Secretary

U.S. Geological Survey

Marcia K. McNutt, Director

U.S. Geological Survey, Reston, Virginia: 2012

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Suggested citation:

Roberts, J.H., and Angermeier, P.L., 2012, Monitoring of endangered Roanoke logperch (Percina rex) in Smith 

River upstream from the Philpott Reservoir on U.S. Army Corps of Engineers property near Martinsville, Virginia: 

U.S. Geological Survey Open-File Report 2012–1221, 11 p.
iii

Contents

Introduction ....................................................................................................................................................1

Objective 1: Estimate population density of Roanoke logperch on USACE property .........................2

Objective 2: Measure and map by suitability class the distribution of habitat suitable 

for Roanoke logperch in the project area ....................................................................................3

Objective 3: Assess water quality relative to Roanoke logperch habitat 

in the project area............................................................................................................................9

Objective 4: Use the data on logperch abundance, habitat suitability, and water 

quality to test the general validity of correlates of logperch abundance 

from other locations.........................................................................................................................9

Objective 5: Identify opportunities and threats related to protecting and enhancing 

Roanoke logperch habitat.............................................................................................................10

Objective 6: Provide suggestions on the necessity and scale of future studies and 

monitoring related to logperch in and near USACE waters....................................................10

References Cited..........................................................................................................................................11

Figures

1. The Smith River at White Falls at the time of sampling, October 9, 2011 ............................2

2. Map showing location of the five sample sites (yellow circles) on the 

Smith River upstream from Philpott Reservoir.........................................................................3

3. Variation in the population density of Age-0 and Age-1+ Roanoke logperch 

among five sites across six years..............................................................................................4

4. Distribution and quality of microhabitat cells at site 1 during fall 2011...............................5

5. Distribution and quality of microhabitat cells at site 2 during fall 2011...............................5

6. Distribution and quality of microhabitat cells at site 3 during fall 2011...............................6

7. Distribution and quality of microhabitat cells at site 4 during fall 2011...............................6

8. Distribution and quality of microhabitat cells at site 5 during fall 2011...............................7

9. Variation among five sites across 6 years in the percentage of sampled 

microhabitat cells featuring “excellent” or “good” Age-1+ Roanoke 

logperch habitat............................................................................................................................7

Tables

1. Observed abundances and estimated densities of Roanoke logperch 

during fall 2011 at five permanent sites in the USACE-owned segment 

 of the Smith River..........................................................................................................................4

2. Distribution of Age-1+ Roanoke logperch habitat suitability classes 

 during fall 2011 at five permanent sites in the USACE-owned segment 

 of the Smith River..........................................................................................................................8

3. Annual variation in the mean and standard deviation of daily discharge 

 of the Smith River during spring and during fall fish sampling, as well 

as the corresponding estimates of overall Roanoke logperch density 

and mean percentage of high-quality microhabitats at sample sites .................................8

4. Interannual correlations between variables shown in table 3 .............................................9

5. Water-quality variables as measured at all sites on October 9, 2011..................................9
iv

Conversion Factors and Abbreviations

SI to Inch/Pound

Multiply By To obtain

Length

millimeter (mm) 0.3937 foot (ft)

meter (m) 3.281 foot (ft)

kilometer (km) 0.6214 mile (mi)

Area

square meter (m2

) 0.0002471 acre 

hectare (ha) 2.471 acre

Temperature in degrees Fahrenheit (°F) may be converted to degrees Celsius (°C) 

as follows:

°C=(°F–32)/1.8

Vertical coordinate information is referenced to the North American Vertical Datum 

of 1988 (NAVD 88)

Horizontal coordinate information is referenced to the North American Datum 

of 1983 (NAD 83)

Abbreviations and Acronyms 

USACE U.S. Army Corps of Engineers

ESA U.S. Endangered Species Act

VT Virginia Tech

VCFWRU Virginia Cooperative Fish and Wildlife Research Unit

IACUC Institutional Animal Care and Use Committee

TL Total length

≤ Less than or equal to

> Greater than

SE Standard error

SD Standard deviation

< Less than

NTU Nephelometric turbidity units

TC Temperature-corrected

Raw Not temperature-corrected

ATV All-terrain vehicle
Monitoring of Endangered Roanoke Logperch (Percina 

rex) in Smith River Upstream from the Philpott Reservoir 

on U.S. Army Corps of Engineers Property near 

Martinsville, Virginia

By James H. Roberts1 and Paul L. Angermeier2

____________________

1

Department of Fish and Wildlife Conservation, Virginia Tech, 

Blacksburg, Virginia.

2

U.S. Geological Survey, Virginia Cooperative Fish and 

Wildlife Research Unit, Blacksburg, Virginia

Introduction 

The purpose of this study was to continue annual monitoring of Roanoke logperch (Percina rex), an endangered 

fish, in the Smith River immediately upstream from Philpott 

Reservoir. This river reach is owned by the U.S. Army Corps 

of Engineers (USACE), which must ensure that appropriate 

actions are undertaken to aid in recovery of logperch. Monitoring of fish abundance and habitat conditions provides a means 

for assessing the species’ status and its responses to USACE 

management actions. 

The Roanoke logperch is a large darter (Percidae: 

Etheostomatinae) endemic to the Roanoke, Dan, and Nottoway River basins of Virginia and North Carolina, where it 

occupies third- to sixth-order streams containing relatively 

silt-free substrate (Jenkins and Burkhead, 1994). Because of 

its rarity, small range, and vulnerability to siltation, the 

Roanoke logperch was listed in 1989 as endangered under 

the U.S. Endangered Species Act (ESA) (U.S. Federal 

Register 54:34468-34472). 

Within the Dan basin, Roanoke logperch have long been 

known to occupy the Smith River and one of its largest tributaries, Town Creek (Jenkins and Burkhead, 1994). Logperch 

also recently were discovered in other tributaries of the Dan 

River, including North Carolina segments of the Mayo River, 

Cascade Creek, Big Beaver Island Creek, Wolf Island Creek 

(William Hester, U.S. Fish and Wildlife Service, personal 

commun., 2012). Within the Smith River, Roanoke logperch 

are present both upstream and downstream from Philpott 

Reservoir, a hydroelectric and water storage project owned 

and operated by the USACE. Although logperch have not been 

observed in the reservoir itself, the species is relatively abundant in a free-flowing, ≈ 2.5-km-long segment of Smith River 

upstream from the reservoir on USACE property (Lahey and 

Angermeier, 2006). This segment is bounded on the downstream end by the lentic conditions of the reservoir and on the 

upstream end by White Falls, a natural waterfall that presumably allows fish passage during all but the lowest streamflows 

(Roberts and Angermeier, 2009; fig. 1).

The ESA stipulates that USACE must ensure that its 

actions do not jeopardize Roanoke logperch and ensure that 

appropriate actions are taken to aid in the recovery of Roanoke 

logperch. USACE recognized that additional information was 

needed to assess compliance with these stipulations, including data on baseline population levels, habitat availability, and 

potential threats to the species on USACE property. USACE 

therefore contracted with Virginia Tech (VT) and the U.S. 

Geological Survey via the Virginia Cooperative Fisheries and 

Wildlife Research Unit (VCFWRU) to continue ecological 

monitoring that was initiated in a pilot study in 2005 (Lahey 

and Angermeier, 2006). The VCFWRU is jointly sponsored by 

the U.S. Geological Survey, Virginia Tech, Virginia Department of Game and Inland Fisheries, and Wildlife Management 

Institute. 

This final report summarizes results of biological monitoring performed by VT and the VCFWRU in 2011, and compares these data to data collected during 2006–2010 (Roberts 

and Angermeier, 2011). Where appropriate, a comparison was 

made to data on Roanoke logperch collected previously in the 

study reach (Lahey and Angermeier, 2006) and in the upper 

Roanoke River (Roberts and Angermeier, 2011). This work 

was performed under the auspices of VT’s Institutional Animal 

Care and Use Committee (IACUC) protocol 11-035-FIW. 

Specifically, the following objectives were addressed:

• Estimate population density of Roanoke logperch on 

USACE property;

• Measure and map by suitability class the distribution of habitat suitable for Roanoke logperch in the 

project area;
2 Monitoring of Endangered Roanoke Logperch (Percina rex) in Smith River near Martinsville, Virginia

• Assess water quality relative to Roanoke logperch 

habitat in the project area;

• Use the data on logperch abundance, habitat suitability,

and water quality to test the general validity of correlates of logperch abundance from other locations;

• Identify opportunities and threats related to protecting 

and enhancing Roanoke logperch habitat; and

• Provide suggestions on the necessity and scale of futur

studies and monitoring related to logperch in and near 

USACE waters.

Objective 1: Estimate population density 

of Roanoke logperch on USACE property

Data were collected between October 9 and 10, 2011 at 

each of the five permanent monitoring sites that were established by Roberts and Angermeier (2007; fig. 2). Each site 

comprised a riffle-run complex that was deemed to contain at 

least some microhabitat configurations that were suitable for 

Roanoke logperch. At each site, an 80-m-long permanent transect parallel to the stream channel previously was established

by driving steel rods into the streambank at 12-m intervals on 

e 

one side of the river (Roberts and Angermeier, 2007). Precise locations of the downstream- and upstream-most rods at 

each site were determined for this report by using a handheld 

geographic positioning system device. During fish and habitat 

sampling (see below) temporary transects were established at 

12-m intervals along the permanent transect (that is, at each 

steel rod) that extended across the stream channel, perpendicular to the permanent transect.

The preferred method for estimating population density 

of Roanoke logperch in fall (September–October) consists of electrofishing into a stationary seine (Roberts and 

Angermeier, 2011). In fall 2010, logperch were captured by 

electrofishing fixed-area net-sets along temporary transects 

(see previous paragraph) at each site. The first net-set was 

positioned on the downstream-most transect of a site, 1 m 

from one of the streambanks. The second quadrat was positioned along the same transect, adjacent to and 1 m from 

the first. As many non-overlapping quadrats as would fit on 

each transect were sampled, given the length of the transect 

(that is, the stream width). Occasionally areas of the stream 

were skipped that, based on best judgment, exhibited velocity too high to position the net or too low to sweep fishes 

into the net. The above procedures were replicated at each 

upstream transect. During electrofishing, a 2-m-tall, 4-m-wide, 

5-mm-mesh bag seine was positioned 4 m downstream from 

Figure 1. The Smith River at White Falls at the time of sampling, October 9, 2011.
Objective 2 3

Figure 2. Location of the five sample sites (yellow circles) on the Smith River upstream 

from Philpott Reservoir.

the transect. Then, beginning 4 m upstream from the transect, 

a backpack electrofisher made three rapid downstream passes 

into the seine. Thus, a 32-m2

 area (4 m wide x 8 m long) was 

sampled by each net-set. Following electrofishing of a net-set, 

the seine was quickly pulled up and hauled to the streambank, 

where captured fishes were processed. Captured logperch were 

pooled across all quadrats in a site to determine the abundance 

of logperch in the site. Logperch abundance subsequently was 

converted to population density (number ha–1) based on the 

area (number of net-sets) sampled at a site.

Captured logperch were sorted into age classes based on 

total length (TL; Roberts and Angermeier, 2011): for fall-captured logperch, fish ≤ 95 mm TL were Age-0 and fish > 95 mm 

TL were Age-1+. After Age-0, fish age cannot be reliably 

determined based on size. Because they are standardized by 

effort, population density estimates can be compared across 

sites and time periods. 

A total of nine Roanoke logperch were captured in 

fall 2011, of which six were Age-1+ and three were Age-0 

(table 1). Population density ranged from 0.0 to 104.2 total 

individuals ha–1 at individual sites and averaged 50.9 total 

individuals ha–1 over all sites. This density was within the 

range observed in previous years.

Annual variation in population density was shown to 

be high at almost all sites for both Age-0 and Age-1+ logperch (fig. 3). The only exception was site 5 (the upstreammost site), which exhibited relatively stable Age-1+ density. 

Spatial peaks and troughs of Age-1+ logperch density did not 

seem to coincide with peaks and troughs of Age-0 logperch 

density. Age-0 density tended to be high at sites 1 and 5 and 

low at sites 2, 3, and 4, whereas Age-1+ density tended to be 

high at site 4 and low at site 1. This lack of correlation is not 

surprising, given that adult and juvenile logperch exhibit preferences for different habitat configurations (Rosenberger and 

Angermeier, 2003). Furthermore, previous genetic findings 

suggested that logperch dispersal within the USACE-owned 

reach was extensive, such that the spatial distribution of Age1+ and Age-0 fish during fall does not necessarily reflect the 

distribution of fish during spawning (Roberts and others, 2008; 

Roberts and Angermeier, 2009). Spatial patterns of Age-1+ 

and Age-0 density are similarly asynchronous in the upper 

Roanoke River (Roberts and Angermeier, 2011).

Objective 2: Measure and map by 

suitability class the distribution of 

habitat suitable for Roanoke logperch 

in the project area

Lack of suitable habitat may be the primary factor 

limiting the distribution and abundance of Roanoke logperch, both rangewide and in the Smith River (Jenkins and 

Burkhead, 1994; Rosenberger, 2007). This, combined with 

the difficulty of estimating logperch abundance given its rarity, suggests that the availability of high-quality habitat may 

provide both a useful index of the viability of the logperch 

population in the Smith River and a means of interpreting 

spatiotemporal variation in logperch abundance. A GIS-based 
4 Monitoring of Endangered Roanoke Logperch (Percina rex) in Smith River near Martinsville, Virginia

Table 1. Observed abundances and estimated densities of Roanoke logperch during fall 2011 at five permanent sites in 

the USACE-owned segment of the Smith River. 

[Abundance and densities were estimated based on numbers of individuals per hectare. Logperch age-classes were distinguished based on fish total 

length. SE represents one standard error]

Site

Site

length 

(meters)

Number

of net-sets

Logperch abundance Logperch density (ha–1)

Age-0 Age-1+ All Age-0 Age-1+ All

1 80 12 0 0 0 0.0 0.0 0.0

2 80 12 0 0 0 0.0 0.0 0.0

3 80 11 0 2 2 0.0 56.8 56.8

4 80 10 1 2 3 31.3 62.5 93.8

5 80 12 2 2 4 52.1 52.1 104.2

Total 400 57 3 6 9

Mean 80 11.4 0.6 1.2 1.8 16.7 34.3 50.9

SE 0 0.4 0.4 0.5 0.8 10.7 14.1 22.2

0

10

20

30

40

50

60

Age-0 logperch

Site 1

Site 2

Site 3

Site 4

Site 5

0

20

40

60

80

100

120

140

160

180

200

2005 2006 2007 2008 2009 2010 2011 2012

Population density (fish/ha)

Age-1+ logperch

EXPLANATION

Site 1

Site 2

Site 3

Site 4

Site 5

EXPLANATION

Figure 3. Variation in the population density of Age-0 (top 

panel) and Age-1+ (bottom panel) Roanoke logperch among 

five sites across six years.

approach to habitat assessment and mapping has been developed and successfully applied in the upper Roanoke River 

(Ensign and Angermeier, 1994; Ensign and others, 1998), 

and application of the methodology to the Smith River was 

described by Roberts and Angermeier (2007). These methods 

were adoped to assess the availability of habitat suitable for 

Roanoke logperch at each Smith River site during fall 2011. 

Maps showing the distribution of suitable and unsuitable 

habitats at each site during fall 2011 are shown in figures 4 

through 8. On average, 24 percent of the habitat cells that were 

sampled at sites featured “high-quality” (good to excellent) 

habitat for Roanoke logperch in fall 2011, whereas 30 percent of the cells featured “low-quality” (poor to unsuitable) 

habitat (table 2). 
Objective 2 5

Unsuitable

Poor

Fair

Good

Excellent

Streamflow 

EXPLANATION

Figure 4. Distribution and quality of microhabitat cells 

(1.5-m2 pixels) at site 1 during fall 2011. Microhabitat 

cells were classified according to suitability for Age-1+ 

Roanoke logperch using transect-based habitat data 

and a habitat suitability index that was developed 

by Ensign and Angermeier (1994) and Ensign and 

others (1998) based on observations of logperch in the 

Roanoke River.

Unsuitable

Poor

Fair

Good

Excellent

EXPLANATION

Streamflow 

Figure 5. Distribution and quality of microhabitat cells 

(1.5-m2 pixels) at site 2 during fall 2011. Microhabitat 

cells were classified according to suitability for Age-1+ 

Roanoke logperch using transect-based habitat data 

and a habitat suitability index that was developed 

by Ensign and Angermeier (1994) and Ensign and 

others (1998) based on observations of logperch in the 

Roanoke River.
6 Monitoring of Endangered Roanoke Logperch (Percina rex) in Smith River near Martinsville, Virginia

Unsuitable

Poor

Fair

Good

Excellent

EXPLANATION

Streamflow 

Figure 6. Distribution and quality of microhabitat cells 

(1.5-m2 pixels) at site 3 during fall 2011. Microhabitat cells were 

classified according to suitability for Age-1+ Roanoke logperch 

using transect-based habitat data and a habitat suitability index 

that was developed by Ensign and Angermeier (1994) and Ensign 

and others (1998) based on observations of logperch in the 

Roanoke River.

Unsuitable

Poor

Fair

Good

Excellent

EXPLANATION

Streamflow 

Figure 7. Distribution and quality of microhabitat cells 

(1.5-m2 pixels) at site 4 during fall 2011. Microhabitat cells were 

classified according to suitability for Age-1+ Roanoke logperch 

using transect-based habitat data and a habitat suitability index 

that was developed by Ensign and Angermeier (1994) and Ensign 

and others (1998) based on observations of logperch in the 

Roanoke River.
Objective 2: Measure and map by suitability class the distribution of habitat suitable for Roanoke logperch in the project area 7

Unsuitable

Poor

Fair

Good

Excellent

EXPLANATION

Streamflow 

Figure 8. Distribution and quality of microhabitat cells 

(1.5-m2 pixels) at site 5 during fall 2011. Microhabitat cells were 

classified according to suitability for Age-1+ Roanoke logperch 

using transect-based habitat data and a habitat suitability index 

that was developed by Ensign and Angermeier (1994) and Ensign 

and others (1998) based on observations of logperch in the 

Roanoke River.

Annual variation in habitat suitability may be related 

to annual variation in the streamflow of the Smith River, 

as estimated by the U.S. Geological Survey streamgaging 

station near Woolwine (table 3). The estimated percentage of high-quality habitat is strongly positively correlated 

with the streamflow during habitat sampling, as well as with 

the mean and standard deviation of streamflow during the 

spring (April 1 through June 30) leading up to the sample 

(table 4). Elevated spring streamflows may scour away previously deposited silt, thereby increasing habitat suitability. 

Elevated streamflows during sampling may increase the depth 

and velocity of microhabitat cells, which increases habitat 

suitability scores.

Patterns of temporal variation in habitat conditions are 

more distinctive than patterns of spatial variation. The availability of high-quality Age-1+ habitat at sites varies consistently among years (fig. 9). That is, if availability of highquality habitat increases (or decreases) between years at one 

site, it tends to increase (or decrease) at all sites. Some spatial 

patterns are also evident. First, site 5 tended to exhibit greater 

availability of high-quality habitat than sites 3 or 4. Second, 

site 3 exhibited less annual variability than other sites, possibly because of its deep morphology and prevalent unsuitable 

bedrock substrate, which make habitat suitability calculations 

at the site less sensitive to hydrologic variation. Furthermore, 

spatial variation in habitat quality did not clearly relate to spatial variation in Age-1+ or Age-0 logperch density. This lack of 

spatial correlation between habitat and logperch density also 

has been observed in the upper Roanoke River (Roberts and 

Angermeier, 2011), and suggests that logperch migrate among 

sites over their lifetimes, and therefore, that recruitment and 

carrying capacity are determined more at the reach scale than 

at the scale of an individual site or riffle.

0

20

40

60

80

100

2005 2006 2007 2008 2009 2010 2011 2012

Percentage excellent or good habitat

Site 1

Site 2

Site 3

Site 4

Site 5

EXPLANATION

Figure 9. Variation among five sites across 6 years in 

the percentage of sampled microhabitat cells featuring 

“excellent” or “good” Age-1+ Roanoke logperch habitat. 

Microhabitat cells were classified using a habitat suitability 

index that was developed by Ensign and Angermeier (1994) 

and Ensign and others (1998) based on observations of 

logperch in the Roanoke River.
8 Monitoring of Endangered Roanoke Logperch (Percina rex) in Smith River near Martinsville, Virginia

Table 2. Distribution of Age-1+ Roanoke logperch habitat suitability classes during fall 2011 at five 

permanent sites in the USACE-owned segment of the Smith River. 

[Column entries are the percentages of the total site area estimated to be in the designated suitability class. SE represents 

one standard error. The habitat suitability index used to evaluate habitats was developed by Ensign and Angermeier (1994) 

and Ensign and others (1998) based on observations of logperch in the Roanoke River]

Site

Suitability classification (percentage of site) Total area

(square meters) Unsuitable Poor Fair Good Excellent

1 16.2 7.9 46.9 22.0 7.1 1905.7

2 7.0 20.2 63.1 9.6 0.1 2031.7

3 6.3 23.6 47.1 16.5 6.5 2553.7

4 25.3 22.2 32.1 18.6 1.8 3064.5

5 4.2 16.0 42.3 37.0 0.5 2110.5

Mean 11.8 18.0 46.3 20.7 3.2 2333.2

SE 4.0 2.8 5.0 4.5 1.5 212.9

Table 3. Annual variation in the mean and standard deviation of daily discharge of the Smith River 

during spring and during fall fish sampling, as well as the corresponding estimates of overall Roanoke 

logperch density and mean percentage of high-quality microhabitats at sample sites. 

[Discharge data were obtained between April 1–June 30 from the U.S. Geological Survey streamgage near Woolwine, Virginia. ft3

, cubic feet; ha, hectare; SD, standard deviation]

Year

Spring

streamflow (ft3

 s-1)

Sampling Overall 

Age-0 Overall Age-1+ Mean percentage

streamflow 

(ft3

 s–1)

logperch 

density

logperch 

density excellent-good

Mean SD Mean (fish ha–1) (fish ha–1) habitat

2006 30.7 36.8 28 13.4 35.7 38.0

2007 48.4 17.8 14 18.4 59.7 23.4

2008 34.3 23.2 10 5.1 56.4 13.0

2009 73.0 50.1 22 13.4 35.7 49.0

2010 46.9 17.9 15 11.6 8.3 41.4

2011 53.3 23.2 12 16.4 32.9 24.0
Objective 3 9

Table 4. Interannual correlations between variables shown in table 3.

[Variables include the mean (SpringMean) and standard deviation (SpringSD) of streamflow of the 

Smith River during spring (April 1–June 30) and streamflow during fish sampling (Sampling), as 

well as estimates of overall Age-0 and Age-1+ Roanoke logperch density and the mean percentage of 

high-quality (good or excellent) habitat at sample sites. Discharge data were obtained from the U.S. 

Geological Survey stream gauge near Woolwine, Virginia. None of these correlation coefficients are 

significantly larger than expected by chance (P < 0.05), but values > 0.5 are highlighted in bold]

SpringMean SpringSD Sampling Age-0 Age-1+

SpringSD 0.46

Sampling 0.01 0.72

Age-0 0.38 –0.02 0.20

Age-1+ –0.18 –0.05 –0.23 –0.01

Habitat 0.51 0.64 0.72 0.23 –0.66

Objective 3: Assess water quality 

relative to Roanoke logperch habitat 

in the project area

Water-quality conditions were measured at each site on 

October 9, 2011 (table 5). All previously measured waterquality variables were measured, with the exception of turbidity, which could not be measured because the turbidimeter 

malfunctioned. As a consequence, turbidity at all sites was 

visually estimated and determined to be < 1 NTU during sampling. Overall, water quality exhibited only minor betweensite variability, which was expected given the proximity of 

the sites to each other. Based on published accounts (Jenkins 

and Burkhead, 1994) and data from the Roanoke River, water 

quality in the Smith River during fall 2011 was well within 

ranges acceptable for use by Roanoke logperch (Roberts and 

Angermeier, 2011).

Objective 4: Use the data on logperch 

abundance, habitat suitability, and 

water quality to test the general 

validity of correlates of logperch 

abundance from other locations

Using regression-tree analyses, Roberts and Angermeier 

(2011) found that temporal variation of logperch abundance in 

the upper Roanoke River partly could be explained by temporal variation in the magnitude of streamflow during the winter 

and spring preceding the sample. Logperch were estimated 

to be more abundant in years during which streamflow was 

moderate and had relatively low variability. Presumably, high 

streamflows cause displacement and/or mortality of logperch, 

but moderate streamflows are necessary to scour silt from 

feeding and spawning habitats.

Table 5. Water-quality variables as measured at all sites on October 9, 2011. 

[Water conductivity was recorded both with (TC) and without (Raw) accounting for water temperature. The 

mean and standard error (SE) of water quality variables across sites are given. The turbidimeter malfunctioned 

on the day of sampling, so turbidity measurements are not given, however, the visual estimate of turbidity was 

less than 1 NTU at all sites. mg/L–1, milligrams per liter; μS, microsiemens; °C, degrees Celsius]

Site pH Turbidity

 (NTU)

Dissolved

oxygen

 (mg/L–1)

Raw

conductivity

 (μS)

TC

conductivity

 (μS)

Water

temperature

 (°C)

1 7.8 – 9.9 48.8 62.9 13.2

2 8.0 – 9.6 51.5 63.2 15.3

3 8.1 – 10.1 52.1 63.6 15.6

4 7.9 – 9.7 51.3 63.6 15.0

5 7.9 – 9.5 51.3 63.7 14.8

Mean 7.9 – 9.8 51.0 63.4 14.8

SE 0.05 – 0.10 0.57 0.15 0.42
10 Monitoring of Endangered Roanoke Logperch (Percina rex) in Smith River near Martinsville, Virginia

Multiple regression analysis is not yet possible in the 

Smith River, because the record contains only 6 years of 

data. However, based on bivariate correlations, logperch 

density does not appear to be strongly related to streamflow 

(tables 3 and 4). Estimated Age-1+ logperch density is weakly 

negatively correlated, and Age-0 density weakly positively 

correlated, with the mean of streamflow during spring (April 1 

through June 30) and with the mean of streamflow during fish 

sampling. Density of both age classes is weakly negatively 

correlated with the standard deviation of spring streamflow. 

In contrast, Age-1+ density is more strongly negatively correlated with the percentage of high-quality habitat. Because 

habitat quality itself is collinear with streamflow, the latter 

relationship was considered spurious. This same, presumably 

spurious, negative correlation between fish density and habitat 

quality has been observed in the Roanoke River. In the 2009 

Smith River report (Roberts and Angermeier, 2010), bivariate 

correlations suggested stronger relationships between hydrologic variability and logperch density. This change in results 

given additional observations indicates the danger of placing 

too much emphasis on such findings and underscores the need 

for longer-term monitoring to understand mechanisms influencing logperch population dynamics.

Objective 5: Identify opportunities 

and threats related to protecting and 

enhancing Roanoke logperch habitat

Foreseeable threats to Roanoke logperch and their 

habitats in the Philpott reach of Smith River appear to be 

minor based on our observations and appear to have remained 

unchanged since our last survey (Roberts and Angermeier, 

2011). Human activity seems uncommon within the USACEowned reach; we obseved no dwellings or roads there. The 

operation of all-terrain vehicles (ATVs) in and near the stream 

may represent the greatest human impact to the Smith River 

within the study reach, given that it creates tracks of exposed 

soil that sloughs into the river during heavy rains. We did not 

assess the prevalence and distribution of ATV activities and 

their impacts “on the ground,” or how these impacts vary over 

time. Such an assessment may be best performed using time 

series of satellite imagery or aerial photography, analyzed in a 

GIS. We did observe relatively few entry points of ATVs into 

the river channel. Limiting access of ATVs to the floodplain 

of the Smith River may protect the banks and channel of the 

river from erosion due to ATV use. The greatest threats to the 

USACE-owned reach may be from increasing urbanization 

and pollution further upstream in the Smith River watershed.

Objective 6: Provide suggestions on the 

necessity and scale of future studies 

and monitoring related to logperch in 

and near USACE waters

If the USACE objectives for managing waters near 

Philpott Reservoir include development of baseline information on the distribution and abundance of Roanoke logperch, 

as well as spatiotemporal variation in these parameters, a 

prudent strategy would be to continue monitoring logperch 

population density, availability of suitable logperch habitat, 

and water quality at the five sites described herein. Annual 

samples, collected in fall (September–October), would provide 

a sound basis for analyzing interannual variation in logperch 

abundance, and potentially lead to greater understanding of the 

factors (for example, the recruitment of juveniles, availability 

of habitat, and hydrologic variability) that regulate logperch 

abundance in the upper Smith River. Such knowledge is 

particularly valuable given the availability of a comparable 

dataset from the upper Roanoke River; analyses of similarities and differences between rivers should provide valuable 

insight into factors regulating logperch abundance overall. 

For example, preliminary comparisons between rivers suggest 

that hydrologic variation may affect the two logperch populations in different ways. Collection of additional samples over a 

wider range of hydrologic scenarios may allow the estimation 

of maximum and/or minimum streamflow thresholds that are 

critical for logperch population dynamics. Such biologically 

linked models could be used to increase the effectiveness of 

conservation efforts for Roanoke logperch, both upstream and 

downstream of the Philpott Reservoir (Orth et al., 2004). 
References Cited 11

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For additional information regarding this 

publication, contact:

Paul L. Angermeier

Virginia Cooperative Fish and Wildlife 

Research Unit

Virginia Tech

Blacksburg, VA 24061-0321

Email: biota@vt.edu

Prepared by:

USGS Science Publishing Network

Raleigh Publishing Service Center

3916 Sunset Ridge Road

Raleigh, NC 27607

Roberts and Angermeier—Monitoring of Endangered Roanoke Logperch (Percina rex) in Smith River near Martinsville, Virginia—Open-File Report 2012–1221