U.S. DEPARTMENT OF THE INTERIOR 

U.S. GEOLOGICAL SURVEY

Aquatic Survey of the Lower Escalante River,

Glen Canyon National Recreation Area, Utah

June 22-26,1998

By

Gordon Mueller, U.S. Geological Survey-MESC; 

2Lewis Boobar, Glen Canyon National Recreation Area;

3Richard Wydoski, Bureau of Reclamation;

4Kristen Cornelia, 4Richard Fridell, and 5Quentin Bradwisch,

Utah Division of Wildlife Resources

Open-File Report 99-101 

Prepared jointly with the National Park Service and Utah Division of Wildlife Resources.

This report is preliminary and has not been reviewed for conformity with U.S. Geological Survey 

editorial standards (or with the North American Stratigraphic Code). Any use of trade, product 

or firm names is for descriptive purposes only and does not imply endorsement by the U.S. 

Government.

'P.O. Box 25007, D-8220, Denver, Colorado 80225 

2P.O. Box 1507, Page, Arizona 86040 

3P.O. Box 25007, D-8220, Denver, Colorado 80225 

4344 E. Sunland Dr., #8, St. George, Utah 84790

5P.O. Box 1446, Page, Arizona 86040
TABLE OF CONTENTS

Page

EXECUTIVE SUMMARY ................................................... iv

INTRODUCTION ........................................................... 1

CHAPTER 1 -- INVERTEBRATES..(By Boobar) .................................. 4

METHODS ........................................................... 4

RESULTS ........................................................... 4

DISCUSSION ......................................................... 8

RECOMMENDATIONS ................................................ 8

REFERENCES ........................................................ 8

CHAPTER 2 -- FISH..(By Mueller, Wydoski, Bradwisch) .......................... 10

METHODS .......................................................... 10

RESULTS ........................................................... 10

DISCUSSION ........................................................ 17

RECOMMENDATIONS ............................................... 19

REFERENCES ....................................................... 20

CHAPTER 3 -- AMPHIBIANS..(By Cornelia and Fridell) .......................... 22

METHODS .......................................................... 25

RESULTS ........................................................... 25

DISCUSSION ........................................................ 28

RECOMMENDATIONS ............................................... 30

REFERENCES ....................................................... 31

APPENDICES

A. PHOTOGRAPHS .................................................. 33

TABLES

Number Page

1.1 Taxonomic list and abundance of aquatic macroinvertebrates 

collected downstream of Harris Wash, Escalante River, Utah 

- 06/22/98 through 06/24/98. Abundance : QN=quantitative 

(per meter squared), QL= Qualitative ................................ 5

1.2 Community summary statistics. Abundance data is number 

per meter squared for quantitative samples and number per 

sample for qualitative samples. EPT = totals for the insect 

orders, Ephemeroptera, Plecoptera, Trichoptera. MHBI = 

Modified Hisenhoff Biotic Index. In site descriptor, 

QL = qualitative and QN + Quantitative samples ....................... 6
Number

1.3 Taxa richness by functional feeding group; number of taxa 

per meter squared for quantitative samples and number of 

taxa per sample for qualitative samples. Numbers in 

parentheses are percentages, In site descriptor, QL = 

qualitative and QN = quantitative samples .............

1.4 Taxa abundance by functional feeding group; abundance per 

meter squared for quantitative samples and abundance per 

sample for qualitative samples. Numbers in parentheses are 

percentages. In site descriptor, QL = qualitative and QN = 

quanitative samples ................................

2.1 Physical measurements (width, depth, length, velocity) 

of stream sites 1,2,3,4,5 sampled on the Escalante River, 

Utah. ......................................................... 12

2.2 Historical record of fish species collected or observed in

the Escalante River, Utah ........................................ 16

2.3 Length, weight, and range data taken from fish collected

In the Lower Escalante River, Utah. ................................ 17

3.1 Amphibians occurring in the lower 100 km of the Escalante 

River including common name, scientific name, and status 

within the State of Utah. Information is based on locality 

data compiled from museum records, grey (unpublished) 

literature, and Tanner (1940) ...................................... 22

3.2 Sampling date, GPS location, survey length, and life stage 

of woodhouse toads observed during 1998 presence/absence 

surveys at 13 sampling stations on the Escalante River, Utah. ............ 26

3.3 Number and lifestage (A=adult, J=juvenile), average water depth 

(cm), ambient temperature, water temperature (°C), and 

microhabitat for woodhouse toad observations at seven survey 

stations between Harris Wash and Fence Canyon, 

Escalante River, UT ............................................. 27

n
3.4 Number and lifestage (A=adult, J=juenile), average water depth 

(cm), ambient temperature, water temperature (°C), and 

microhabitat for woodhouse toad observations at six survey 

sites located between Fool's Canyon and the Lake Powell 

confluence, Escalante River, UT ......................... 29

Number

2.1

2.2

FIGURES

Species composition offish collected from the lower 

portion of the Escalante River and its side canyons 

during June 22-26, 1998 .......................

Length distribution of fish captured in the lower 

portion of the Escalante River and its side canyons 

during June 22-26, 1998 .....................

13

14

2.3

3.1

3.2

Fish capture based on equipment selectivity .......................... 15

Amphibian sampling reaches, Escalante River, UT, 

June 22, 1998 to June 26, 1998 ................ 23

Historic distribution of amphibians within the lower 

100 km of the Escalante River, UT. Locality information 

was compiled from museum records, grey (unpublished) 

literature, and Tanner (1940) ....................... 24

Number

MAP

1. Map showing the location of the sites sampled on 

the mainstem Escalante River during June 1998 .

in
EXECUTIVE SUMMARY

A 5 member survey team, representing U.S. Geological Survey, National Park Service, and Utah 

Division of Wildlife Resources surveyed the invertebrate, fish, and amphibian communities of 

the lower 80 km reach of the Escalante River. The objective was to begin gathering baseline 

biological information on the more remote sections of this unique watershed. The survey ran 

through June 22 to June 26, 1998. A total of eight sample sites were examined, four located 

between Harris Wash and Fence Canyon (10 km) and four between Fool's Canyon and Coyote 

Gulch. Sample sites were distanced, approximately 3 km apart.

A total of 475 macroinvertebrates representing 19 taxa were collected, 116 from the upper reach 

and 359 from the lower reach. The dominant families were Chironomidae, Hydrosychidae, 

Simuliidae, and Tricorythidae. Diversity was fairly constant throughout the study area as was the 

MHBI, which summarizes the overall pollution tolerances of the taxa collected.

Over 300 fish were collected representing 3 native and 8 normative species. This survey adds 

two additional species, striped bass (Morone saxatilis) and yellow bullhead (Ictalurus natalis), to 

the 14 species previously reported. The mainstem river between Harris Wash and Fence Canyon 

is remarkably endemic, consisting of roundtail chub (Gila robusta), speckled dace (Rhinichthys 

osculus), and flannelmouth sucker (Catostomus latipinnis). Of the 88 fish collected from the 

mainstem, 87 (99%) were native. Downstream sites were dominated by non-natives which 

constituted 89% of our collections. Red shiner were quite abundant making up 85% of the fish 

collected downstream of Fools Canyon. Permanent pools found in side canyons were dominated 

by green sunfish and fathead minnows. It appears the mainstem native community is relatively 

stable, since species composition has changed little during the past 25 years.

Amphibian inventories were conducted at 13 stations, 7 in the upper and 6 in the lower reach. 

Five amphibian species have been documented in the study area, including the Great Basin 

spadefoot (Spea intermontanus), canyon treefrog (Hyla arenicolor), Northern leopard frog (Rana 

pipiens), red-spotted toad (Bufopunctatus), and woodhouse toad (Bufo woodhousei). Surveys 

encountered 15 adults, 200 juveniles, 1,975 tadpoles, and 3 egg strands, all being Woodhouse 

toads. The absence of the other species may be attributed to the timing of the sampling.

This open-file report provides a discription of one field trip. It was not intended to represent an 

extensive survey effort nor a complete analysis of field data. This report represents a repository 

of field data, observations and discriptions of ecological conditions in June 1998, and provides 

some recommendations for resource managers.

IV
INTRODUCTION

The U.S. Geological Survey (USGS), in cooperation with National Park Service, Fish and 

Wildlife Service, and Utah Division of Wildlife Resources, has been studying the fish 

communities found in the confluences and tributaries of Lake Powell, Utah. Research has 

focussed on the native and non-native fish communities found at the confluence of the San Juan 

River and Lake Powell, with specific interest in the endangered razorback sucker (Xyrauchen 

texanus). These research tasks were finished in 1997 and remaining project resources were 

refocused in 1998.

National Park Service requested that remaining resources and time be directed at the Escalante 

River that lies within the boundaries of Glen Canyon National Recreation Area. The Escalante 

River in an extremely remote stream with little known about its aquatic community. We know of 

only one previous attempt to survey the lower river's fish community and that was conducted by 

Dr. Paul Holden in the early 1970's before Lake Powell filled (1980).

An extensive baseline inventory would demand resources and time that far exceeds this study. 

National Park Service (NPS) prepared a joint, 5-year study proposal with the Grand StaircaseEscalante National Monument (GLCA 1997). A task force was created to evaluate and make 

recommendations pertaining to the proposal. Members represent NPS, Bureau of Land 

Management, Utah Division of Wildlife Resources (UDWR), and Forest Service. The 

committee recommended the USGS effort be developed as a pilot survey, not only to examine 

aquatic resources, but to also assess collection techniques and problems associated with difficult 

access. This information provides additional survey information for UDWR's river drainage 

management plan.

A 5 member, survey team was formed of state and federal biologists, for the purpose of 

conducting a baseline survey of invertebrates, fish, and amphibians found in the middle and 

lower reaches of the Escalante River. The survey ran through June 22 to June 26, 1998.

Site Description The Escalante River drains approximately 830 km2 portions of Garfield and 

Kane counties, Utah. There are approximately 800 km of active stream within the watershed. Its 

headwater is formed by Pine, Mamie, Sand, and Calf creeks which enter the Escalante upstream 

of Highway 12. Waters are diverted from the river to Wide Hollow Reservoir, an off stream 

storage facility. Pine Creek supports approximately 2,000 of irrigated crop land. Downstream of 

Highway 12 the river enters the Escalante Canyon, a remote sandstone canyon bracketed by the 

Kaiparowits Plateau to the west, Circle Cliffs to the North, and Lake Powell to the south. 

Headwaters are located within Dixie National Forest and lower portions of the drainage flow
through Grand Staircase Escalante National Monument and Glen Canyon National Recreation 

Area. An excellent discription of the physical attributes of the drainage is presented in 

Ottenbacher and Hepworth (1999).

The stream is relatively small but flows are highly erratic do to spring run-off and flash flooding 

during the summer monsoon season (Appendix A). Low base flows that are aggravated by 

irrigation diversions. The furthest downstream gauging station (#09337500) is located near the 

town of Escalante, Utah, which is relatively high in the water shed. Additional base and storm 

flows are contributed to the river by tributaries or side canyons such as: Boulder Creek, Harris 

Wash, Silver Falls Creek, Twenty-five Mile Wash, Moody Canyon, Stevens Canyon, and Coyote 

Gulch.

Sampling was conducted in two sections of the river's lower 80 kms which provided access and 

extraction by helicopter or by boat. This was necessary do to the absence of roads. The 

upstream section was located between Harris Wash and Fence Canyon (10 km). The survey 

team was dropped off at Harris Wash and backpacked downstream sampling and photographing 

four sites located at 3 km intervals (Map 1 & Appendix A). Here the canyon floor is relatively 

broad and the stream meanders through a well developed riparian corridor composed of willow, 

cottonwood, and tamarisk. Stream habitat is dominated by run and riffle habitat as it drops an 

average of 3.2 m/km. Stream bank undercutting and riparian vegetation in some areas provide 

overhead cover and diverified habitat for aquatic animals. Deep pools or backwaters were rare or 

absent. The stream bed was composed primarily of sands and gravels.

Fence Canyon had several small, entrenched pools, that were formed by rock depressions and 

clay. One was sampled that was located approximately 100 m upstream of the Canyon's 

confluence with the river.

Sampling in the lower most river reach was completed between Fool's Canyon and Coyote 

Gulch (Map 1). In this area the river enters a narrow canyon. Stream gradient decreases (2.1 

m/km) and the stream bed and banks are littered with rock rubble and large (>4 m) boulders. 

Fine sands replace gravels as the predominate substrate size and riparian vegetation is restricted 

to colonizing tamarisk and willow. Cover is limited to washouts formed around large boulders 

and rock rubble.

Another changes occurs further downstream at Steven's Canyon where the number of large 

bounders diminish and the stream bed becomes broader and shallower. The substrate is 

dominated by sands and fine gravels and there are narrow stands of dense willow and tamarisk. 

Sediment deposition is obvious not only in the mainstem river but also up Coyote Gulch. It's 

believed sediment loading is influenced by reservoir elevations. Again, sampling was conducted 

at 3 km intervals in this 10 km reach.
Upper Study Sites (1-4)

GPS Coordinates

Site# UTMx UTMy

1. 481013 4168401

2. 482546 4166119

3. 482546 4164200

4. 484200 4162874

5. 501509 4144965

6. 501406 4144565

7. 501074 4143872

8. 501532 4143206

Lower Study Sites (5-8)

Map 1. Map showing the locations of the sites sampled on the mainstem Escalante River during 

June 1998.
CHAPTER 1--INVERTEBRATES

By Lewis Boobar (NFS) 

METHODS

A total of 16 Surber (30 X 30 cm sample area, 500 um net) samples (Merritt and Cummins 1996) 

were collected from riffles along the lower Escalante River. Two of the 16 samples were 

collected from each of four riffles (sites), four from the upper and four from the lower reaches 

(Map 1). Additionally, 30 minutes were spent at each site collecting macroinvertebrates from 

debris and snags. The samples and associated water were mixed with 95% ethyl alcohol to 

obtain a concentration (ca. 50% ethyl alcohol) high enough to temporarily preserve the animals. 

Later, samples were composited by type and river-section. The resulting two composite Surber 

samples and two composite qualitative samples (one of each type from each river-section) were 

processed by the Bureau of Land Management and U.S. Forest Service National Aquatic 

Monitoring Center at Utah State University, Logan, UT as described by Vinson and Hawkins 

(1996). Initially, the entire sample was sorted for large and less-numerous organisms. If the 

sample contained more than 250 organisms, it was sub-sampled. They took additional 

sub-samples until at least 250 organisms are found. The identified portion of the sample was 

placed in 70% ethyl alcohol, cataloged, and archived. The data was entered into a common 

computer database at the National Aquatic Monitoring Center. This database currently contains 

aquatic macroinvertebrate data and corresponding geographic information for more than 4000 

samples.

RESULTS

A total of 475 macroinvertebrates representing 19 taxa were collected, 116 from the upper reach 

and 359 from the lower reach (Table I.I, Appendix A). The dominant families were 

Chironomidae, Hydrosychidae, Simuliidae and Tricorythidae (Table 1.2). Diversity was fairly 

constant throughout the study area as was the Modified Hilsenhoff Biotic Index 

(MHBI)(Hilsenhoff 1987, 1988; Bode et al. 1991), which summarizes the overall pollution 

tolerances of the taxa collected, and the USGS Community tolerant quotient (Wingett and 

Mangum 1979). The taxa richness (Table 1.3) and abundance (Table 1.4) of functional feeding 

groups showed collector gatherers and collector filters to be slightly greater in the lower reach, 

and scrapers to be slightly greater in the upper reach.
Table 1.1. Taxonomic list and abundance of aquatic macroinvertebrates collected 

downstream of Harris Wash, Escalante River, Utah - 06/22/98 through 

06/24/98. Abundance: QN = quantitative (per meter squared), 

QL = Qualitative.

Phylum 

Class 

Order 

Family 

Subfamily/Genus/species

Annelida

Oligochaeta

Haplotaxida

Tubificidae

Arthropoda

Arachnoidea

Hydracarina

Insecta

Coleoptera

Elmidae

Microcylloepus

Microcylloepus

Stenelmis

Gyrinidae

Gyrinus

Diptera

Chironomidae

Orthocladiinae

Tanypodinae

Simuliidae

Prosimulium

Prosimulium

Simulium

Ephemeroptera

Baetidae

Baetis tricaudatus

Callibaetis

Heptageniidae

Heptagenia

Tricorythidae

Tricorythodes

Hemiptera

Corixidae

Neocorixa

Naucoridae

Ambrysus

Odonata

Gomphidae

Erpetogomphus compositas

Trichoptera

Trichoptera

Hydropsychidae

Hydropsyche

Hydroptilidae

Mollusca

Gastropoda

Basommatophora

Physidae

Physella

Total: 19taxa

Life 

Stage 

L/P/A

A

A

L

L

A

A

A

L

L

L

P

L

L

L

L

L

L

A

A

L

L

P

L

L

A

Abundance

upper-' upper- lowerQL QN QN 

106721 106722 106723

3

1

1

2 3

3

1

1

3 17

1 1

1

1

24 8

8 6 40

3 1

15 3

9 9 15

1 1

1

7

1

13 71

35 81 161

lowerQL 

106724

119

9

6

13

1

14

1

2

22

10

1

198

1. Numbers listed under QN and QL allows cross referencing to Bureau of Land 

Management and U.S. Forest Service National Aquatic Monitoring Center Database.
Table 1.2. Community summary statistics. Abundance data is number per meter squared for quantitative 

samples and number per sample for qualitative samples. EPT = totals for the insect orders, 

Ephemeroptera, Plecoptera.Trichoptera. MHBI = Modified Hilsenhoff Biotic Index. 

In site descriptor, QL = qualitative and QN = quanitative samples.

Assemblage Abundance Measures

Site

Upper-QL

Upper-QN

Lower-QN

Lower-QL

Date

6/23/98

6/22/98

6/24/98

6/24/98

Sample ID 1

106721

106722

106723

106724

Total

abundance

35

81

161

198

EPT2

abundance

27

43

132

66

#of

families

8

11

8

10

Dominant

family

Tricorythidae

Simliidae

Hydrosychidae

Chironomidae

Dom. Family

abundance

9

24

71

119

Dom. Family

% contribution

25.71

29.63

44.1

60.1

Diversity Indices

Upper-QL

Upper-QN

Lower-QN

Lower-QL

6/23/98

6/22/98

6/24/98

6/24/98

106721

106722

106723

106724

Total

taxa

richness

8

13

10

11

EPT

taxa

richness

4

4

6

6

Shannon

diversity

1.851

2.023

1.573

1.44

Simpson

diversity

0.159

0.161

0.277

0.385

Evenness

0.983

0.792

0.685

0.495

Biotic Indices

USFS 

Biotic Condition Index4

Upper-QL

Upper-QN

Lower-QN

Lower-QL

6/23/98

6/22/98

6/24/98

6/24/98

106721

106722

106723

106724

MHBI3

2.61

4.06

3.97

4.93

Indication

Slight organic enrichment

Moderate organic enrichment

Slight organic enrichment

Moderate organic enrichment

CTQa

89

96

89

95

CTQd

87

94

96

100

1. Allows cross referencing to Bureau of Land Management and U.S. Forest Service National Aquatic 

Monitoring Center Database.

2. Ephemeroptera, Plecoptera, Trichoptera - ratio considered sensitive to pollution.

3. Modified Hilsenhoff Biotic Index - summarizes the overall pollution tolerances of the taxa collected.

4. Community toerant quotient - integrates biological, physical and chemical parameters.
Table 1.3. Taxa richness by functional feeding group; number of taxa per meter squared for quantitative 

samples and number of taxa per sample for qualitative samples. Numbers in parentheses 

are percentages. In site descriptor, QL = qualitative and QN = quanitative samples.

Site

Upper-QL

Upper-QN

Lower-QN

Lower-QL

Date

6/23/98

6/22/98

6/24/98

6/24/98

Sample ID 1

106721

106722

106723

106724

Shredders

0(0)

0(0)

0(0)

1(9)

Scrapers

1(13)

2(15)

2(20)

1(9)

Collector 

filterers

1(13)

2(15)

2(20)

2(18)

Collector 

gatherers

5(50)

4(31)

4(40)

5(45)

Predators

1(13)

5(38)

1(10)

1(9)

Unknown

1(13)

0(0)

1(10)

1(9)

1. Allows cross referencing to Bureau of Land Management and U.S. Forest Service National Aquatic 

Monitoring Center Database.

Table 1.4. Taxa abundance by functional feeding group; abundance per meter squared for quantitative samples 

and abundance per sample for qualitative samples. Numbers in parentheses are percentages. 

In site descriptor, QL = qualitative and QN = quanitative samples.

Site

Upper-QL

Upper-QN

Lower-QN

Lower-QL

Date

6/23/98

6/22/98

6/24/98

6/24/98

Sample ID 1

106721

106722

106723

106724

Shredders

0(0)

0(0)

0(0)

10(5)

Scrapers

3(9)

16(20)

4(2)

1(1)

Collector 

filterers

3(9)

37(46)

79(49)

31(16)

Collector 

gatherers

22(63)

23(28)

75(47)

153(77)

Predators

1(3)

5(6)

1(1)

2(1)

Unknown

7(20)

0(0)

1(1)

1(1)

1. Allows cross referencing to Bureau of Land Management and U.S. Forest Service National Aquatic 

Monitoring Center Database.
DISCUSSION

The macroinvertebrate abundance in the lower Escalante have not been previously studied. The 

upper reaches above the confluence of The Gulch and the Escalante River and tributaries were 

sampled incidental to a survey of threatened and endangered fish (McAda et al. 1977). That 

study showed that Baetis sp. was ubiquitous throughout the sampling area and Rhyacophila sp. 

dominated headwaters, where as Tipulids and Anisopterans were more prevalent in the lower 

reaches of the study area. Vinson (1998) collected samples from the upper reaches of the 

Escalante River, tributaries and a couple of Tinajas. That study found about 70 taxa. Plecoptera 

were only collected from Steep Creek, which is a tributary of The Gulch. The Trichopteran 

Rhyacophila was not collected during the 1998 survey.

Rivers naturally change as they flow downstream. Riverain vegetation conditions, light, 

temperature, hydraulics, and substrate composition all change and in response to these 

environmental changes macroinvertebrate communities change. The macroinvertebrate 

abundance in the lower Escalante was low compared to the data collected from the upper 

Escalante by Vinson (1998). This is not that unusual for river drainages. Vinson sampled in 

early June when the water level was low. Just before we sampled the lower reaches the water 

level was elevated. Sampling was confined to the edge of the river due to the high water and 

scouring could have reduced the abundance. Because this is the first information on 

macroinvertebrates from the lower Escalante River it begins to establish baseline data against 

which future data can be compared.

RECOMMENDATIONS

Inventory: A comprehensive study that samples the macroinvertebrates within the mainstem and 

tributaries of the Escalante at various times of the year should be conducted. This study should 

include the entire watershed and should not be confined to NFS lands. The data collected would 

provide the spatial and temporal information required for selecting water quality monitoring sites 

within the watershed.

Monitoring: As a minimum the NFS should establish a long term monitoring site on the lower 

Escalante located at the north face of Steven's Arch (UTMx501532y4143206). This site can be 

accessed by hiking down Coyote Gulch. A suite of physical and chemical parameters should be 

collected with the macroinvertebrate data to help detect changes in water quality. Other sites 

might need to be added as information from the inventory is gathered.

REFERENCES

Bode, R. W., M. A. Novak, and L. E. Abele. 1991. Methods for Rapid Biological Assessment 

of Streams. New York Department of Environmental Conservation. Albany, New York.
Hilsenhoff, W. L. 1988. Rapid Field Assessment of Organic Pollution with a Family Level 

Biotic Index. The Journal of the North American Benthological Society. 7:65-68.

Hilsenhoff, W. L. 1987. An Improved Index of Organic Stream Pollution. The Great Lakes 

Entomologist. 20:31-39.

MaAda, C., C. Philips, C.R. Berry, and R.S. Wydoski. 1977. A Survey of Threatened and 

Endangered Fish in Southeastern Utah Streams. Utah Cooperative Fishery Research 

Unit, Contract No. 77-8236, Logan Utah pp 245.

Merritt, R. W. and K. W. Cummins. 1996. An Introduction to the Aquatic Insects of North 

America. Kendall-Hunt Publishing Company, Dubuque, Iowa.

Vinson, M. R. 1998. Aquatic Benthic Macroinvertebrate Monitoring Report. U.S.D.I. Bureau 

of Land Management Aquatic Ecosystem Laboratory, Logan, Utah.

Vinson, M. R. and C. P. Hawkins. 1996. Effects of Sampling Area and Subsampling Procedure 

on Comparisons of Taxa Richness Among Streams. The Journal of the North American 

Benthological Society 15:392-399.

Wingett, R.N. and F.A. Mangum. 1979. Biotic condition indexf:integrated biological, physical, 

and chemical parameters for management. U.S. Forest Service Intermountain Region, U.S. 

Department of Agriculture, Ogden, UT.
CHAPTER 2--FISH

By Gordon Mueller (USGS), Richard Wydoski (BOR), and Quentin Bradwisch (UDWR)

METHODS

Sampling was conducted to determine fish community composition, relative abundance, and 

changes since previous surveys (Holden and Irvine 1975) and to examine sampling gear 

efficiency. Sampling techniques included both active and passive netting techniques using the 

following equipment: a 6 mm bar mesh (1.3 X 10 m) seine, a 12 mm (1.3 x 15 m) trammel net, a 

80 cm diameter, 2 hoop fyke net, and two collapsible minnow traps.

Sampling was conducted on the declining limb of spring runnoff and weather conditions were 

relatively cool and dry. The river was turbid, carrying a substantial sediment and debris load. 

Visibility was <10 cm which made it difficult to sample or make any visual observations. Gage 

reading at the headwaters of the Escalante River (station#09337500) fell from 32 to 6 cfs during 

the course of the survey. Downstream tributaries contributed additional flows increasing the 

river to an estimated volume of 155 cfs (131-191 cfs [3.7-5.4 m3/s]).

A small volume (<2 cfs) of water was flowing from Harris Wash and Coyote Gulch but the 

stream beds at Fence, Choprock, and Steven's canyons were dry. The flow from Harris Wash 

was broad (3-5 m) and quite shallow (2-5 cm) and we observed schools of small (<3 cm) suckers 

and speckled dace. Fence Canyon had a series of spring fed pools, some more that a meter deep 

and several meters in length. The pools supported what appeared to be multi year classes of 

green sunfish and fathead minnows which suggests the pools are permanent features. These are 

the same species reported to be common in pools found in other side canyons by both Holden 

and Irvine (1975) and McAda et al. (1977). Slightly more water (est 2-4 cfs) was flowing from 

Coyote Gulch. At its confluence with the river it formed a large (7-10 m), long (50 m), shallow 

pool (0.5 m) that was full of tadpoles. We walked upstream approximately 1 km. The stream 

bed was composed of fine, drifting sand. Only a couple of small fish (suckers or dace ?) were 

observed.

Flow Measurements Physical measurements of the reach's length, width (3 locations), midchannel depths, and maximum depth were recorded. Surface water velocities were measured by 

timing floats released in mid-channel. A gross flow estimate was calculated using the following 

formula: R= ^y2^ , were R = volume (mVsec), W = stream width, Da = depth X constant .8 for 

bottom roughness, L = length, and T = average float time in seconds (Lagler 1950). Other more 

complex as well as smaller areas were sampled but not measured.

Seining The seine was used to collect both quantitative and qualitative information. At each 

study site a reach relatively free of major obstructions was sampled using three-pass, depletion 

seining. Prior to sampling the trammel net was set downstream to block fish escape. The 

sample reach was seined starting upstream and working toward the blocking net. Fish collected

10
from each seine haul were held in live nets. Following sampling, fish were identified, counted, 

measured and weighted.

Fyke Net A single throated fyke net constructed of 6 mm nylon netting, 2.5 m in length, with 

two 76 cm hoops was set with the entrance facing downstream in deep channels where velocities 

held the net upright. Time of sets ranged from 1 to 10 hours.

Minnow Traps Two collapsible, 2 mm mesh minnow traps (30 cm x 30 cm x 45 cm) were set it 

in slack water habitats near shore. Time of sets ranged from 1 to 10 hours.

Trammel Net A 15 cm outer and 1.2 cm inter panels trammel net measuring 1.3 by 15 m was set 

in or near deeper holes or backwaters. Trammel nets were typically set overnight.

RESULTS

Physical measurements were taken at the first 5 sampling sites where the river was smaller, more 

channelized and could effectively be seined (Table 2.1). The primary purpose of measuring 

sample area was to calculate fish densities and biomass per surface area or habitat volume. 

Unfortunately, due to high flows and velocities (>3.0m3/>lm/s) it was not possible to effectively 

seine the study sites.Seining was difficult for the lack of suitable sites and high (>1 m/sec) river 

velocities. Appropriate seining sites having suitable depth, velocities, and unobstructed reaches 

were uncommon. This might not be the case at lower flows.

We also had problems finding sites with adequate depth (>1 m) and lengths (>3 m) to set the 

fyke net. The trammel net proved to be the biggest challenge. There were essentially no 

backwater or pool habitats. We would normally set a portion of the trammel net (<7 m) in eddie 

pools behind large boulders. The net was fished 3 nights, 2 of which produced fish. The 

trammel produced the second highest species diversity: roundtail chub, flannelmouth sucker, 

carp, and stripped bass. It also provided good information on adult fish that are difficult to seine 

and provide information on reproductive status.

Insufficient data was collected to allow density or biomass estimates. Field information is 

limited to individual fish data, relative abundance, and species persence. Stream measurements 

were not taken at sites 6, 7, and 8.

Fish Survey efforts yielded 306 fish, representing eleven species (Table 2.2). We encountered 

two new species, yellow bullhead and striped bass new not previously reported for the drainage 

and brown trout which were not reported that far downstream by Holden and Irving (1975). We 

did not encountered largemouth bass nor bluehead sucker which were previously reported.

11
Eighty nine fish, representing 4 (99%) indigenous species, were collected in the mainstem river 

between Harris Wash and Fence Canyon (Figures 2.0). We encountered multiple year classes 

(possibly 4) of roundtail chub, flannelmouth sucker (4-5), and green sunfish (2-3) (Figure 2.1).

Roundtail chub were spawning, males were tuberculate and in breeding colors and we collected 

one ripe female. We encountered only one non-native upstream of Fence Canyon; a juvenile 

brown trout. Length and weight information is provided in Table 2.3 and Figure 2.2.

Table 2.1 Physical measurements (width, depth, length, velocity) of sites 1, 2, 3, 4, 5 sampled on 

the Escalante River, Utah.

Site

Sitel

Average

Site 2

Average

Site 3*

Average

Site 4

Average

Site 5*

Average

Width 

(m)

9.8

8.5

7.6

8.6

0.4

10.7

9.8

10.3

4.9

5.2

4.9

5.0

7.6

9.8

11.3

9.6

4.8

4.0

2.1

2.2

Length Depth 

(m) (m)

38.7 .53

.61

.67

.60

43.3 .38

.38

.45

.40

30.5 .31

.38

.38

.33

21.3 .38

.45

.53

.45

29.0 .31

.27

.45

.34

Max. Depth Travel Time 

(m) (sec)

.98 33

55

40

43

.68 35

36

34

35

.53 19

22

20

21

.53 19

18

18

18

.53 39

41

41

40

Volume (cfs) 

(m3/s)

3.72 (131)

5.40 (191)

1.92 (68)*

4.09 (144)

0.43 (15)*

* measurement of side channel.

12
SPECIES COMPOSITION

UPPER REACH

(N = 89)

SPECKLED DACE 40.4%

ROUNDTAIL CHUB 15.7%

I BROWN TROUT 1.1%

JUVENILE SUCKER 13.5%

FLANNELMOUTH SUCKER 29.2%

FENCE CANYON 

((N = 20)

GREEN SUNFISH 45.0%

FATHEAD MINNOW 40.0%

JUVENILE SUCKER 15.0%

LOWER REACH 

(N = 197)

RED SHINER 86.3%

SPECKLED DACE 2.0%

FLANNELMOUTH SUCKER 9.1%

THERS 2.5%

CHANNEL CATFISH 

CARP

STRIPED BASS 

YELLOW BULLHEAD

Figure 2.1. Species composition of fish collected from the lower portion of the Escalante River 

and its side canyons during June 22-26, 1998.

13
18

15

I

w 12

u.

u_

FLANNELMOUTH SUCKER

SSSiSSSSiSSSS 

TOTAL LENGTH

S g

ROUNDTAIL CHUB

._..._.I-- - 

I

r~ -

r4*4DflOOr4*<D4DOr4*4DflOONTr«fl0O

TOTAL LENGTH

o

5

I 

co 4

LL 

LLi 3 LU

CO

i 2

1

0

SPECKLED DACE

I

'

TOTAL LENGTH

S S g S 

TOTAL LENGTH

OF FISH NUMBER O MCO>

FATHEAD MINNOW

-

B

II 

eo o>

GREEN SUNFISH

TOTAL LENGTH

ooooooooooo

TOTAL LENGTH

Figure 2.2. Length distribution of fish captured in the lower portion of the Escalante River 

and its side canyons during June 22-26, 1998)

14
to

U)

tfl

PERCENT OF SPECIES CATCH 

MINNOW TRAP

TRAMMEL NET

m

§

PERCENT OF SPECIES CATCH

M yi -J 

01 o in

MINNOW TRAP

TRAMMEL NET

M

TR

PERCENT OF SPECIES CATCH PERCENT OF SPECIES CATCH 

CD

MINNOW TRAP

TRAMMEL NET

O 

70 m m

CO

c 

z

Tl

CO

MINNOW TRAP

TRAMMEL NET

MINN

TRAM
There wasn't any surface flow from Fence Canyon, however, the canyon had several small pools 

that are entrenched in the bedrock. It appears small springs maintain these pools year-round. 

One pool, approximately 1 m deep, 4 m wide and 10m long was sampled by seine and trammel 

net. Twenty fish were captured. Green sunfish (45%) were the most numerous, followed by 

fathead minnow (40%) and juvenile suckers (15%).

Table 2.2. Historical record of fish species collected or observed in the Escalante River, Utah.

Common Name Scientific Name Holden & Irvine McAda et. al 1998

(1975) (1977)

Flannelmouth Sucker

Bluehead Sucker

Roundtail Chub

Speckled Dace

Red Shiner

Fathead Minnow

Carp

Channel Catfish

Yellow Bullhead

Striped Bass

Largemouth Bass

Green Sunfish

Brown Trout

Rainbow Trout

Cuttthroat Trout

Brook Trout

Trout hybrids

(Catostomus latipinnis)

(Pantosteus discobolus)

(Gila robustd)

(Rhinichthys osculus)

(Cyprinella lutrensis)

(Pimephales promelas)

(Cyprinius carpio)

(Ictalurus punctatus)

(Ictalurus natalis)

(Morone saxatilis)

(Micropterus salmoides)

(Lepomis cyanellus)

(Salmo trutta)

(Salmo gairdneri)

(Salmo clarki)

(Salvelinus fontinalis)

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X*

X*

X

X

*Not previously reported

The reach downstream of Fool's canyon was predominately exotic (89%). A total of 197 fish 

were captured. Red shiner made up 86% of the catch followed by flannelmouth sucker (9%), 

speckled dace (2%), and miscellaneous others (3%) which included two new species: a 172mm 

yellow bullhead and a 600mm striped bass (Figure 2.1).

Sampling Gear Sampling techniques were quite selective for some species and sizes offish 

(Figures 2.2 & 2.3). For instance nearly all (85%) the roundtail chub were collected by fyke net. 

The fyke net also targeted larger suckers (>10 cm) and while its mesh size was relatively small 

(6 mm), few small fish (speckled dace or red shiners) were collected by the fyke net. This 

would suggest smaller fish might have been concentrated along shoreline (fringe) habitats rather 

than mid-stream. This contention is also supported by the fact that smaller fish were captured by 

the minnow traps and the seine along shore.

16
Table 2.3. Length, weight, and range data taken from fish collected in the Lower Escalante 

River, Utah during June 22-26, 1998.________________________

Species___________#____x Length (mm) (Range) # x Weight (gr) (Range)

Flannelmouth sucker 41 144 (36-400) 18 98 (6-320)

Roundtail chub 14 196 (83-313) 12 98 (25-275)

Specked dace 36 56 (36-84) 0 --

Red shiner 88 52 (32-78) 0 --

Fathead minnow 9 50 (44-54) 0 --

Carp 1 440 -- 1 1,000

Channel catfish 2 77 (72-82) 0 --

Yellow bullhead 1 172 1 16

Green sunfish 8 73 (45-137) 0 -

Striped bass 1 600 - 1 1,650

Brown trout 1 62 0 --

DISCUSSION

Habitat The dissimilarities in habitat reflected three, distinct fish communities. As reported by 

Holden and Irvine (1974) there is a distinct change in both stream morphology and community 

structure between the middle and lower portions of the Escalante River. Habitat complexity and 

amplitude of hydraulic cycles must have a significant influence on fish community structure. 

The middle canyon represents a fairly broad floodplain which is typically channelized by a well 

developed riparian corridor bordered by willow, cottonwood and tamarisk. The combination of 

bank cutting and well developed riparian corridors provides ample overhead cover in the form of 

vegetative shade and exposed roots mass where fish can hide from predators, feed, spawn, or find 

refuge from the current. There is abundant evidence that high flood flows frequently swell and 

overbank, inundating seasonal side channels. The occurrence of woody vegetation, large snags, 

and piles of flood debris on higher benches of the floodplain would provide ample cover for fish 

during floods. The river was relatively shallow with few areas deeper than 1 m. Any habitat that 

could be categorized as pool, were extremely small with depths never exceeding 1.5 m. 

Typically, the stream was channelized with a mixture of undercut and gravel banks.

Downstream of Scorpion Gulch, the river enters and travels through a narrow and confined 

canyon to Lake Powell. The river has an entrenched channel. Vegetation was absent or 

extremely rare, being limited to young stands of willow, tamarisk, and weeds. The stream bed 

was strewed with large boulders, rock rubble, and fines. Cover was typically limited to rock 

interspace and deep pools caused by river hydraulics and rock outcroppings. During flooding, 

the canyon would pose extremely hostile conditions. The hostile environment may benefit 

endemic species by negatively impacting nonnatives.

17
Community Structure We found three distinctly different fish communities: the middle portion 

of the river basin, the lower portion, and the side canyons. The native fish community found 

between Harris Wash and Fence Canyon was remarkably intact. Sampling suggests that 

speckled dace, roundtail chub, and flannelmouth sucker are still abundant as they were nearly 25 

years ago (Holden and Irvine 1975). The maintainance or enhancement of this native fish 

community is identified as a management objective (Ottenbacker and Hepworth 1999). The 

roundtail chub is listed as threatened by Utah and the flannelmouth sucker is a state Species of 

Special Concern. Of the 88 fish collected from the mainstem, 87 (99%) were native. No red 

shiners or largemouth bass were collected. Our native sample composition was higher than the 

65% endemism reported by Holden and Irvine (1975), however, they sampled side canyons 

where exotics were quite common. In Holden and Irvine's narrative, they discussed sampling 

Harris Wash, Steven's Canyon, and Coyote Gulch where they found pools dominated by nonnative fishes.

They also reported that non-native species dominated (95%) the lower mainstem community as 

well as the side canyons. We found similar conditions. Non-natives made up 89% of the fish 

collected in the side canyons and lower sampling sites. Red shiner were quite abundant making 

up 85% of the fish collected downstream of Fools Canyon. We also collected adult carp 

(440 mm) and striped bass (600 mm) which undoubtedly migrated upriver from Lake Powell.

The native fish community is bracketed, both up- and downstream by exotic fish communities. 

The river's head waters support 4 species of non-native trout. Side canyon pools throughout the 

basin have been reported to contain large numbers of red shiner, fathead minnow and green 

sunfish (Holden and Irvine 1975, McAda et al. 1977). Our survey identified two additional 

exotics; the yellow bullhead and striped bass, one of which undoubtedly migrated upstream from 

Lake Powell. Undoubtedly, individuals periodically seed the mainstem during spring and storm 

runoff. It's not only encouraging, but also interesting that the middle canyon has remained 

essentially intact during the past 25 years. The resiliency of the endemic fish community 

between Harris and Fence Canyons must be partially in response to rather harsh, summer 

conditions where apparently, only natives can survive. The differences in physical habitat types 

is striking, especially in considering the conditions that fish face through the full range of annual 

flood and drought cycles.

Potential Threats It appears that during the past 25 years the native/non-native fish community 

has remained relatively stable. While this is somewhat reassuring, the fish community will 

always be threatened by human activities that proliferates pollution, further water depletion, and 

the spread of additional fish species and their parasites and pathogens.

Previous reports did not address the possibility that fish are, or can, migrate from Lake Powell. 

The presence of common occurring largemouth bass, channel catfish, carp, and green sunfish 

may have resulted of bait bucket introductions or their escape from upstream ponds. However, 

the absence of largemouth bass and channel catfish from the extensive surveys conducted by 

McAda et al. (1977) suggests these species may have migrated upstream from the reservoir.

18
Holden and Irvine (1975) observed largemouth bass and carp throughout our study area and 

reported largemouth bass were found in breeding pairs. During our survey the river was 

extremely turbid which didn't allow similar sightings, however, we strongly suspect largemouth 

may still be found in relatively low numbers.

We also encountered two new species: a yellow bullhead and striped bass. While the origin of 

the yellow bullhead can be questioned, the striped bass undoubtedly came from Lake Powell. 

Striped bass commonly run up rivers to spawn when water temperatures reach between 15 to 20 

°C (Moyle 1976) and are reported to run up the Colorado and San Juan Rivers to spawn 

(Gustavenson 1982). The fish was an adult and would not have survived summer river 

temperatures (>27 °C) (McAda et al. 1977, Moyle 1976).

The smallmouth bass (Micropterus dolomieui) is a relatively recent introduction to Lake Powell 

that could directly and indirectly threaten the Escalante native fishery. While none have been 

collected or reported, they have established an impressive reservoir fishery making up an 

estimated 20% of Lake Powell's creel (Blommer and Gustaveson 1997). Smallmouth bass were 

first introduced in 1982 through a decade long stocking program. Fish were stocked at 21 

reservoir locations, which included the Escalante River Arm of Lake Powell (Blommer and 

Gustaveson 1997).

Smallmouth bass are actually better suited for small streams than largemouth bass. Habitats used 

by smallmouth bass are quite similar to those used by roundtail chub. In Arizona, smallmouth 

bass have replaced roundtail chub populations in the Verde and Salt rivers (Minckley 1973). 

While smallmouth bass will prey directly on native fish, they also pose an indirect threat by 

spreading the bass tapeworm. Lake Powell smallmouth bass have been reported to have a high 

infestation (Blommer and Gustaveson 1997).

RECOMMENDATIONS

Monitoring We recommend that surveys be conducted downstream of Fence Canyon to 

determine the transition area where non-native fishes become more abundant. The reasons why 

exotics have been able to expand their range in other streams and not in the middle portion of the 

Escalante River deserves closer examination.

We would recommend that a monitoring program be establish to periodically (about every 5 

years) monitor the fish community at selected sampling sites. The mainstem river contained an 

intact native fish community that could easily be impacted.

Sampling Equipment Recommendations The sampling techniques we used worked well in 

remote reaches where equipment had to be packed in. Seining would be the most effective 

sampling method during low flows. Our efforts were less effective because of higher than 

normal flows.

19
If another trip were planned, we would recommend the following gear: 1 seine (6 mm mesh II. 3 

X 7 m), 2-trammel nets (1.3 by 8 m in length), 4-6 minnow traps, 4 fyke nets (2-50 and 

2-80 cm diameter), and light fishing gear. If the survey crew had access to horses or a helicopter 

a backpack shocker should also be considered.

REFERENCES

Blommer, G.L. and A.W. Gustaveson. 1997. Smallmouth Bass in Lake Powell, 1982-1996. 

Sport Fish Restoration Act Project F-46-R. March 1997, Publication No. 97-9. 

Utah Department of Natural Resources, Salt Lake City, pp 59.

Gustavenson, W.A., T.D. Pettengill, J.R. Wahl, and J.E. Johnson. 1982. Lake Powell Fisheries 

Investigations, Publication No. 82-6, DJ Project F-28-R-10. Utah State Division of 

Wildlife Resources.

Holden, P.B., and J.R. Irvine. 1975. Ecological Survey and Analysis of the Aquatic and 

Riparian Fauna and Flora of Escalante Canyon, Utah. Contract No. CS 12004 B034, 

Final Report to National Park Service and Cooperative Research Unit, Utah State 

University, Logan, Utah.

Karp, C., and G. Mueller. 1996. Annual Report of Razorback Sucker Telemetry Study in the 

Lower San Juan River, Utah. 1996. Bureau of Reclamation, Denver Technical Service 

Center, D-8220, Denver, Colorado.

Lagler, K.F. 1950. Studies in Freshwater Fishery Biology. Edwards Brothers, Inc, Ann Arbor, 

Michigan pp 231.

MaAda, C., C. Philips, C.R. Berry, and R.S. Wydoski. 1977. A Survey of Threatened and 

Endangered Fish in Southeastern Utah Streams. Utah Cooperative Fishery Research 

Unit, Contract No. 77-8236, Logan Utah pp 245.

Minckley, W.L. 1973. Fishes of Arizona. Arizona Game and Fish Department, Phoenix, 

pp 293.

Moyle, P.B. 1976. Inland Fishes of California. University of California Press, Berkeley. 

pp405.

Mueller, G., and R. Wydoski. 1995. Fish survey of San Juan River inflow area of Lake Powell, 

March 13-28, 1995. National Biological Service, Denver, Colorado.

20
Mueller, G., and P.C. Marsh. 1998. Post-stocking dispersal, Habitat use, and behavioral 

acclimation of juvenile razorback suckers in two Colorado River reservoirs. U.S. 

Geological Survey Open-File Report 98-301, Denver, Colorado.

Ottenbacker, M.J., and D.K. Hepworth. 1999. Aquatic Management Plan Escalante River

Drainage Hydrologic Unit 14070005. Utah Division of Wildlife Resoures, Salt Lake City, 

Utah. pp. 24.

Sigler, W. F., and R. R. Miller. 1963. Fishes of Utah. Utah State Department of Fish and 

Game, Salt Lake City, Utah, pp 203.

21
CHAPTER 3-AMPHIBIANS

By Kristen M. Cornelia and Richard A. Fridell (UDWR)

In June 1998, amphibian presence/absence surveys were conducted by the Utah Division of 

Wildlife Resources (UDWR) during an interagency sampling trip on the lower Escalante River. 

Surveys were conducted to determine the occurrence and geographic distribution of amphibians. 

Amphibian inventories were conducted at 13 stations within the lower 80 km (50mi) of the 

Escalante River. The lower 80 km of the Escalante River was divided into two sampling reaches. 

The upper reach, located between Harris Wash and Fence Canyon (Figure 3.1), contained seven 

survey stations. The lower reach, located between Fool's Canyon and the confluence of Lake 

Powell (approximately 0.75 miles below Coyote Gulch) (Figure 3.1), contained six survey 

stations.

Historic distribution of amphibians in the lower Escalante drainage (Figure 3.2) was determined 

by compiling locality information from museum records, unpublished literature, and Tanner 

(1940). Five amphibian species have been historically documented in the lower 100 km of the 

Escalante River, including the Great Basin spadefoot (Scaphiopus intermontanus), canyon 

treefrog (Hyla arenicolor), Northern leopard frog (Rana pipiens}, red-spotted toad (Bufo 

punctatus), and woodhouse toad (Bufo woodhousei) (Figure 3.2, Table 3.1).

Table 3.1. Amphibians occurring in the lower 100 km of the Escalante River including common 

name, scientific name, and status within the State of Utah. Information is based on 

locality data compiled from museum records, unpublished literature, and Tanner 

(1940).

Common Name Scientific Name Status 

Great Basin Spadefoot Scaphiopus intermontanus Native 

Leopard Frog Rana pipiens Native 

Canyon Treefrog Hyla arenicolor Native 

Woodhouse Toad Bufo woodhousei Native 

Red-spotted Toad________Bufo punctatus_____________Native_________

22
 Upper Sampling Reach

Harris Wash

Fence Canyon

Fools Canyon £

CoyoljiJGulch ,j'

V X -^

10 20 Kilometers

N

A

Figure 3.\. Amphibians sampling reaches, Escalante River, UT, June 22 - 26, 1998.

23
S Twenty-fweMleWash

0 10 20 Kilometers

 Scaphiopus intermontanus 

Rana pipiens

 Hyla arenicolor

 Bufo woodhousei

 Bufo punctatus

N

A

Figure 3.2. Historic distribution of amphibians within the lower 100 km of the Escalante River, 

UT. Locality information was compiled from museum records, unpublished 

literature, and Tanner (1940).

24
METHODS

Sampling techniques for surveying amphibians included both Visual encounter (VE) surveys 

(Crump and Scott 1994) and call counts (Zimmerman 1994). Visual encounter surveys were 

conducted at all stations by walking along the river channel and systematically searching for 

amphibians. During VE surveys a single person searched both sides of the channel. Bank cover 

was not turned over or disrupted; only those individuals visible on the surface were counted. At 

each station, reaches approximately 0.20 mi in length were targeted for VE surveys. However, 

due to habitat heterogeneity and time limitations, survey distance and search time varied among 

stations. Typically, channel right was searched while walking downstream and channel left was 

searched while returning to the upstream starting point. Any seeps or side canyons within the 

station were surveyed for a maximum distance of 0.25 mi. Amphibians captured during 

sampling were identified, snout-vent length measured (mm), and released. Total survey time, 

station length, number of individuals encountered and life stage, water temperature, ambient 

temperature, and GPS location were recorded at each station.

Approximate counts were conducted for all tadpoles and egg strings encountered. Each egg 

string was assigned an age class according to stage of development. Age classes were designated 

as follows: Class 1) string below water surface and resting on substrate or vegetation, envelopes 

clear and ova small, dark and round; Class 2) string starting to float to surface, envelopes opaque 

and ova kidney-shaped or elongated; Class 3) string at water surface and top layer of eggs crusty 

due to desiccation, embryos have tails and are close to hatching; Class 3+) string starting to 

disarticulate and often yellow in color, most of the embryos have hatched from the eggs and are 

feeding on the string or swimming freely as tadpoles; Dead) embryos desiccated or white to gray, 

with disarticulation of both the embryos and egg string.

When tadpoles were encountered a sample of 10 was collected. Samples were used for 

confirmation of species and stored for future tissue analysis. All samples were preserved in 95% 

ethanol. Tadpoles collected were verified using a dissecting scope and a dichotomous key (Altig 

1970) developed by Gosner (1960).

Call count surveys were conducted near dusk at 2 stations. At each station, ten minute voice 

counts were conducted at two separate locations approximately 0.10 mi apart. Thirteen stations 

within two reaches, totaling 8.65 miles of habitat, were surveyed (Table 3.2). Total search time 

was 16 person hours.

RESULTS

The woodhouse toad (Bufo woodhousei) was the only amphibian species documented. All life 

stages of this species were observed, including juvenile (n=200) and adult toads (n=19), tadpoles 

(n=2425), and egg strings (n=4) (Table 3.2). In addition, two calling woodhouse toads were 

recorded. Woodhouse toads were observed at 10 of 13 stations (Table 2).

25
Table 3.2. Sampling date, GPS location, survey length, and life stage of woodhouse toads 

observed during 1998 presence/absence surveys at 13 sampling stations on the 

Escalante River, Utah. Tadpole numbers in parenthesis are estimates.

Station 

Number

Upper

I 1

2 1

3 1

41

5 1

6 1

72

Lower

8 1

9 1

10 1

II 2

12'

13 1

Date

6-22-98

6-22-98

6-22-98

6-23-98

6-23-98

6-23-98

6-23-98

6-24-98

6-24-98

6-25-98

6-25-98

6-26-98

6-26-98

UTMx

481013

482257

482524

483214

483536

483970

484247

501642

501386

501191

501746

501714

501986

UTMy

4168401

4167280

4165951

4165111

4164325

4164025

4162639

4144696

4144219

4143611

4143089

4142111

4141540

Only Visual encounter surveys conducted at this station.

Survey 

length

0.10 mi

0.10 mi

0.50 mi

0.10 mi

0.20 mi

0.40 mi

2.0 mi

0.50 mi

2.0 mi

0.50 mi

1.75 mi

0.40 mi

0.10 mi

a

Toads

1

l a

1

0

0

0

1

1

5

2

204

0

5

Tadpoles

(50)

(100)

0

0

0

0

(300)

(100)

0

(250)

(625)

(1000)

0

Egg strings 

(Age)

0

0

1(1)

0

0

0

0

1(2)

2 (Dead)

0

0

0

0

Dead B. woodhousei, partial remains only.

Upper Reach (Harris Wash to Fence Canyon); Woodhouse toads were observed at 4 of 7 

stations surveyed in the upper reach (Table 3.3). Observations included adults (n=4), tadpoles 

(n=450), and a single egg string. Six surveys were conducted on the mainstem of the Escalante 

River (stations 2-1 a) and resulted in 3 adult toads, approximately 100 tadpoles, and 1 egg string 

(Table 3.3). Tadpoles (n=100) and the remains of a dead adult toad were located in an offchannel pool at station 2 (Table 3.3). A single adult toad was observed along the channel at 

stations 3 and 7a. The single egg string (Age Class 1) was located in an off-channel pool at 

station 3. No amphibians were located at stations 4, 5, or 6. Water temperature in the mainstem 

Escalante River was 19°C; temperatures in the off-channel pools averaged 20°C (Table 3.3).

26
Table 3.3. Number and lifestage (A=adult, J=juvenile), average water depth (cm),

ambient temperature, water temperature (°C), and microhabitat for woodhouse toad 

observations at seven survey stations between Harris Wash and Fence Canyon, 

Escalante River, UT.

Station 

Number

1

2

3

4

5

6

T

7b

T(A)°C

27

29

24

-

-

26

26

26

T

O/^ 

(W) ^

22

21

19

19

19

19

17

23

# Observed/ 

Lifestage

U

1A 1

1A

0

0

0

1A

0

Tadpole # 

(depth cm)

50(4)

100(5)

0

0

0

0

0

300 (5)

Egg string # 

(depth cm)

0

0

1(5)

0

0

0

0

0

Microhabitat

Side wash

Off-channel pool

River bank & offchannel pool

-

-

-

River bank

Isolated pools in 

side canyon

Partial remains of dead adult found in off-channel pool. 

Mainstem Escalante River 

Fence Canyon

Surveys were also conducted in two tributaries to the Escalante River, Harris Wash (Station 1) 

and Fence Canyon (Station 7b). A single adult toad and approximately 350 tadpoles were 

observed (Table 3.3). Water temperatures in Harris Wash and Fence Canyon were 22°C and 

23 °C, respectively. In Fence Canyon seven isolated pools were surveyed; only two contained 

amphibians. The five pools not containing amphibians supported populations of green sunfish 

(Lepomis cyanellus), fathead minnow (Pimephales promelas), and juvenile Catostomus sp. Of 

the approximately 450 tadpoles recorded in the upper reach, 78% (n=350) were located in side 

canyons. Tadpoles were typically found aggregated in shallow (<5cm), warm (20°C to 23 °C), 

ephemeral pools in both the mainstem and side canyon stations (Table 3.3).

Call counts were conducted in Fence Canyon on the evening of June 23, 1998. No calling 

amphibians were recorded.

Bank cover among all upstream stations was predominantly willow, cottonwood, tamarisk, and 

Russian olive, however, Equisetum sp., Juncus sp., Typha sp., and Phragmites sp. were also 

common. The river bank substrate was primarily sand, gravel, and cobble.

27
Lower Reach (Poors Canvon to Lake Powell confluence): Woodhouse toads, in various life 

stages, were observed at all six stations surveyed in the lower reach. Observations included 

juvenile (n=200) and adult (n=15) toads, tadpoles (n=1975), and egg strings (n=3). Surveys were 

conducted at 5 stations (8-1 la, 13) on the mainstem of the Escalante River and resulted in 14 

adult toads, approximately 800 tadpoles, and 3 egg strings (Table 3.4). The adult toads were 

observed at stations 8-1 la, and 13 (Table 3.4). All toads were found along the channel less than 

5 m from the water's edge. Tadpoles were observed in off-channel pools at stations 8, 10, and 

1 la, at an average depth of 7 cm (Table 3.4). An off-channel pool at station 1 la had dried up 

leaving approximately 50 tadpoles dead. In addition, 2 dead egg strings, the result of a dried 

pool, were observed at station 9. Woodhouse toads (n=2) were heard calling at station 13, 

however, call counts were not officially conducted at this station. These were the only 

amphibian vocalizations heard during the entire survey period. The water temperature of the 

mainstem and off-channel pools averaged 22 °C and 25 °C respectively.

Two tributaries, Stevens Canyon (Station 1 Ib) and Coyote Gulch (Station 12), were also 

surveyed. A single adult toad, approximately 200 metamorphs, and approximately 1175 tadpoles 

were observed (Table 3.4). Water temperatures in Stevens Canyon and Coyote Gulch averaged 

24°C and 12°C respectively. Within Stevens Canyon, approximately 175 tadpoles were 

observed in two isolated pools (at an average depth of 5.5 cm) (Table 3.4). In addition, one adult 

toad and approximately 200 metamorphs (11mm SVL) were located in an isolated pool 0.25 

miles up the canyon. Approximately 1000 tadpoles, in various developmental stages, were 

observed in Coyote Gulch. Of the approximately 1975 tadpoles observed in the lower reach, 

59% (n=l 175) were located in side canyons.

Call counts were conducted in Stevens Canyon on the evening of June 25, 1998. No calling 

amphibians were recorded.

Bank cover in the lower reach was predominantly willow, tamarisk, Phragmites sp., Equisetum 

sp., and Juncus sp. The river bank substrate was primarily sand, gravel, and cobble.

DISCUSSION

Although five amphibian species have been historically documented in the lower Escalante River 

drainage (Table 3.1), woodhouse toads were the only amphibian species observed during the 

interagency sampling trip. This may be attributed to the timing of the sampling. Woodhouse 

toads, red-spotted toads, Great Basin spadefoot toads, leopard frogs, and canyon treefrogs are all 

seasonal breeders. Timing of breeding activity is variable among all five species, however, it 

typically occurs from March to June, peaking in April and mid-May (Stebbins 1985, Wright and 

Wright 1995). These species may not have been observed because the surveys occurred at the 

end of the breeding activity period.

28
Table 3.4. Number and lifestage (A=adult, J=juvenile), average water depth (cm),

ambient temperature, water temperature (°C), and microhabitat for woodhouse toad 

observations at six survey stations between Fool's Canyon and the Lake Powell 

confluence, Escalante River, UT.

Station 

Number

8

9

10

10

ll a

ll a

ll a

ll b

ll b

12

13

T1 of* MA) ^

-

31

26

26

31

31

31

30

30

20

23

T

O/"1 

A\\A V_^

19

24

19

21

25

25

33

22

26

12

-

# Observed/ 

Lifestage

U

2A, 3J

1A, U

0

0

3A

0

0

1A, 200J

0

3J

Tadpole # 

(depth cm)

100 (6)

0

0

250 (5)

200 (8)

0

200 (9), 

50 (Dry pool)

175 (5.5)

0

1000 (6in)

0

Egg string # 

(depth cm)

1(3)

2 (Dry pool)

0

0

0

0

0

0

0

0

0

Microhabitat

River bank; offchannel seep & pool

River bank; dry pool

River bank

Off-channel pool

Off-channel pool

River bank

Off-channel pools

Pools in side canyon

Pool in side canyon

Side canyon

River bank

Mainstem Escalante River 

Stephens Canyon

In addition to temporal variation in breeding, these species exhibit different breeding behaviors 

and habitat requirements. Spadefoot toads are secretive, spending long periods of time 

underground. Breeding activity occurs following spring and summer rains (Stebbins 1985). As 

a result, this toad is seldom encountered and annual timing of breeding is unpredictable. Canyon 

treefrogs inhabit intermittent or permanent streams, preferring to breed in quiet boulder strewn 

pools with solid, rocky bottoms (Stebbins 1985). Suitable canyon treefrog habitat was not 

observed on the lower mainstem Escalante River. However, suitable habitat may exist in 

unsurveyed side canyons. Red-spotted toads are primarily nocturnal. They are typically 

observed among streamside rocks in intermittent streams, however, they occasionally frequent 

open floodplains, breeding in temporary pools following spring runoff (Stebbins 1985). While 

preferring open marshes, ponds, and reservoirs, leopard frogs also inhabit permanent seeps, 

springs, and slow-moving streams with dense aquatic vegetation (Stebbins 1985). Breeding 

habitat consists of shallow, open water with submerged aquatic vegetation. While suitable redspotted toad and leopard frog breeding habitat was observed in both the mainstem and side 

canyons, surveys did not coincide with the optimal breeding activity period.

Woodhouse toads are typically found in close proximity to permanent water sources including 

rivers, streams, ponds, and irrigation ditches. Woodhouse toads inhabit sandy areas, breeding in 

standing pools and shallow flowing stream reaches (Stebbins 1985, Sullivan 1986, Wright and

29
Wright 1994). Our results document that the lower 80 km of the Escalante River provides 

suitable habitat for Woodhouse toads, with breeding populations existing in both the mainstem 

and side canyons. In the upper and lower sampling reaches, woodhouse toads were associated 

with shallow flowing channels, off-channel pools, and seeps. Sixty-three percent (n=1525) of 

tadpoles were located in side canyons. Both Fence and Stevens Canyon, with isolated, warm 

(22 °C - 26 °C) pools, and Harris Wash and Coyote Gulch, with flows less than 2cfs, provided 

suitable breeding habitat.

The Escalante River is characterized by seasonal high flows resulting from spring runoff and 

rainfall. On the mainstem and side canyons, amphibian breeding habitat is restricted to shallow 

flowing channels, springs, seeps, and backwaters and off-channel pools created by receding high 

water. Temporal variation in the availability of breeding habitat may impact the distribution of 

amphibians. In addition, the distribution of suitable amphibian breeding habitat is limited by the 

presence offish (Hayes and Jennings 1986). In the lower Escalante River, woodhouse toads 

were found breeding in ephemeral areas providing submarginal habitat for fish. Non-native 

fishes pose a greater threat to amphibians than native fishes because their habitat requirements 

overlap with that of breeding amphibians. Amphibian population fragmentation and declines, as 

a result of predation and competition by non-native fishes, have been documented throughout 

western North America (Orchard 1992, Corn 1994). Many non-native fishes (e.g. Lepomis sp., 

Pimephales sp.) are adapted to quiet pools and backwater areas and are highly tolerant of poorly 

oxygenated intermittent streams unsuitable for native fishes (Page and Burr 1991). Hayes and 

Jennings (1986) reported that surveyed localities with non-native fishes rarely supported native 

ranid populations. When amphibians and non-native fishes were sympatric, ranid populations 

were small, suggesting factors were marginal for their survival. In Fence Canyon, within the 

lower Escalante drainage, tadpoles were observed only in isolated pools lacking non-native 

fishes. Amphibian distribution within the lower Escalante River is limited by availability of 

ephemeral habitat associated with spring runoff. Utilization of this breeding habitat by 

amphibians may be limited by competition with non-native fishes.

Breeding populations of woodhouse toads occur in both the mainstem and side canyons of the 

lower Escalante River. While woodhouse toads were the only amphibian species observed in the 

lower drainage, suitable breeding habitat exists for spadefoot toads, red-spotted toads, and 

leopard frogs. Suitable habitat on the mainstem Escalante was not observed for canyon treefrogs, 

however, it may exist in side canyons. Breeding habitat in the lower drainage is ephemeral, and 

availability and utilization are impacted by temporal variation and the presence of fish. The 

timing of amphibian surveys annually is critical in order to coincide with optimal breeding 

activity.

RECOMMENDATIONS

Further inventory, detailing species occurrence and distribution, is necessary prior to establishing 

long term monitoring of amphibian species within the Escalante River. To maximize amphibian 

encounters, we recommend conducting intensive inventories earlier in the breeding season,

30
coinciding with peak amphibian breeding and daily activity periods. Call count and VE 

techniques should be utilized and surveys should be conducted on both the mainstem and side 

canyons. Thorough investigation of side canyons should be conducted as they may provide 

more available breeding habitat, associated with seeps, springs, and seasonal runoff.

REFERENCES

Altig, R. 1970. A key to the tadpoles of the continental United States and Canada. 

Herpetologica. 26:180-207.

Corn, P.S. 1994. What we know and don't know about amphibian declines in the west. Pages 

59-67 in W.W.I Covington and L.F. DeBano (technical coordinators), Sustainable 

ecological systems: Implementing an ecological approach to land management. USD A 

Forest Service, Rocky Man. Forest and Range Experiment Station, Ft. Collins, CO. 

General Technical Report RM-247.

Crump, L.M., and NJ. Scott, Jr. 1994. Visual encounter surveys. Pages 84 - 92 in W.R. Heyer, 

M.A. Donnelly, R.W. McDiarmid, LC. Hayek, and M.S. Foster, eds. Measuring and 

monitoring biological diversity. Standard methods for amphibians. Smithsonian 

Institution Press, Washington.

Gosner, K.L. 1960. A simplified table for staging anuran embryos and larva with notes on 

identification. Herpetologica. 16:183-190.

Hayes, M.P., and M.R. Jennings. 1986. Decline of ranid frog species in western North America: 

are bullfrogs (Rana catesbeiand) responsible? Journal of Herpetology 20:490-509.

Orchard, S.A. 1992. Amphibian population declines in British Columbia. Pages 10 - 13 in C.A. 

Bishop and K.E. Pettit, eds. Declines in Canadian amphibian populations: designing a 

national monitoring strategy. Canadian Wildlife Service. Occ. Paper 76. 120pp.

Page, L.M., and B.M. Burr. 1991. A field guide to freshwater fishes of North America north of 

Mexico. Houghton Mifflin Company, Boston.

Stebbins, R.C. 1985. A field guide to western reptiles and amphibians. Houghton Mifflin 

Company, Boston.

Tanner, V.M. 1940. Abiotic study of the Kaiparowits region of Utah. Great Basin Naturalist. 

1:97-126.

Wright, A.H., and A. A. Wright. 1995. Handbook of frogs and toads of the United States and 

Canada. Comstock Publishing Company, Inc., Ithaca, NY.

31
Zimmerman, B.L. 1994. Audio strip transects. Pages 92 - 97 in W.R. Heyer, M.A. Donnelly, 

R.W. McDiarmid, LC. Hayek, and M.S. Foster, eds. Measuring and monitoring 

biological diversity. Standard methods for amphibians. Smithsonian Institution Press, 

Washington.

32
APPENDIX A

Photographs

An aerial view of the Escalante River taken somewhere between Fence Canyon and Twentyfive 

Mile Wash. This section of the river is typical of the Middle Canyon where the floodplain is 

confined to a relatively broad corridor. This section supports a relatively intact endemic fish 

community.

33
Sample Site #2. Trammel net being used as a blocking net during seining.

Sample Site #3. Looking upstream, the seining station was the left channel.

34
Sample Site #4. Looking downstream to the confluence of the Escalante River and Fence 

Canyon.

Fence Canyon Site. Isolated pool in Fence Canyon located approximately 100 m upstream 

from the Escalante River (note trammel net).

35
''' ife'l

Sample Site #5. Looking upstream. Seining station was located further downstream.

Sample Site #6. Looking downstream. Typical of entire reach, channel obstructed with 

large boulders and rock rubble.

36
Sample Site #7. Looking downstream. Typical of entire reach, channel obstructed with 

large boulders and rock rubble.

fc

Escalanbe River Hear Escalante, Ub 

Station Hunber: 09337500

1972 1977 1982 1987 1992

Legend: Discharge, in CFS

 Estimated Discharge, in CFS

Historical Streamflow Daily Values Graph for Escalante River near Escalante, UT (09337500)

37