U.S. DEPARTMENT OF THE INTERIOR 

U.S. GEOLOGICAL SURVEY

MOVEMENT PATTERNS, BEHAVIOR, AND HABITAT USE OF

RAZORBACK SUCKER STOCKING INTO THE GREEN RIVER AT

CANYONLANDS NATIONAL PARK, UTAH

By

'Dean K. Foster, University of Northern Arizona, Flagstaff 

2Gordon Mueller, U.S. Geological Survey, Midcontinent Ecological Science Center

Open-File Report 99-107

Prepared in cooperation with the National Park Service, U.S. Fish and Wildlife Service, and Utah

Department of Natural 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.

1 311 '/2 S. Lonetree Rd. Flagstaff, AZ 86001

2 D-8220, P.O.Box 25007, Denver, CO 80225
TABLE OF CONTENTS

EXECUTIVE SUMMARY .............................................. iiii

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

MATERIALS AND METHODS ............................................ 4

Sources and Transportation of Fish .................................... 4

Tagging ......................................................... 4

Tracking Design and Effort .......................................... 5

Habitat Use ....................................................... 6

Equipment Performance ............................................. 7

Data Analysis ..................................................... 7

RESULTS ............................................................. 8

Individual Movements - Distance From Release Point..................... 8

Individual Movements - Estimated Rates of Movements .................. 11

Individual Movements -Significance of Movements Within Millard Backwater

and Fish Condition Factor (K) ................................. 11

Individual Habitat Use and the Effects of Condition Factor ................ 12

Comparison of Treatments: Movement Patterns and Habitat Use ............ 14

DISCUSSION ......................................................... 15

Dispersal Patterns................................................. 15

Habitat Use...................................................... 18

A Potential Explanation for the Large Initial Dispersal of Stocked Fish ....... 19

CONCLUSIONS AND RECOMMENDATIONS ............................. 20

ACKNOWLEDGMENTS ................................................ 21

LITERATURE CITED .................................................. 22

APPENDICES ......................................................... 44
TABLES

Number Page

1. A summary of the sampling dates, locations, and total river kilometers 

scanned for tags. The information given below the table summarizes the 

surveying efforts .............................................. 27

2. A summary of fish movements within Millard Bottom backwater during

the acclimation period June 16-19. Fish 1 to? placed into backwater June 16

atl 615-2003 hr, and fish 8 to 15 placed into backwater June 17 at

0900-1047 hr .................................................. 28

3. Razorback sucker utilization of four habitat categories during three time

periods ....................................................... 29

4. Razorback sucker utilization of three current categories during three time

periods ....................................................... 30

5. Razorback sucker utilization of three water depths categories during three

time periods ................................................... 31

6. Condition factors of fish observed to use one of four habitat types are shown

below as a function of both treatment and time period .................. 32

7. Condition factors of fish observed to use habitats subjected to three different 

current intensities are shown below as a function of both treatment and time 

period .......................................................... 33

8. Summarize the condition factors of razorback suckers that utilized habitats

ranging from <1.2, 1.2-3.0, and >3m deep during three time periods. Razorback 

suckers inhabiting 1.2- to 3.0-m deep water have higher condition factors 

than fish in either shallower or deeper water, irregardless of treatment or time 

since release ..................................................... 34

11
FIGURES

Number Page

1. A general map of the project site located in the Southwestern United States ... 35

2A. The following 9 graphs show the dispersal distances (km) for razorback

suckers in the experimental treatment. Fish 15E was the only sucker to still 

remain in the Green River by the end of the project....................... 36

2B. The following 14 graphs show the dispersal distances (km) for razorback 

suckers in the control treatment. Four graphs could not fit on this page 

and are shown in the next Figure (3C) ................................. 37

2C. These graphs are a continuation of Figure 3B............................38

3 A. The following graphs show both the average rates of movements as well 

as the net direction of travel (+/-km/day) for experimental treatment fish. 

The best-fit lines are used to emphasize the general patterns for each fish ... 39

3B. The following graphs show both the average rates of movements as 

well as the net direction of travel (+/-km/day) for control treatment 

fish. The best-fit lines are used to emphasize the general patterns 

for each fish......................................................40

4. Plots of condition factor (K = [weight(grams)* 100]/[length(mm)3] vs. 

length(A) and weight(B). K is positively correlated with weight 

(p = 0.02), but not with length (p = 0.97, B)............................. 41

5. The following two graphs depict daily flow rates of the Colorado 

and Green Rivers within Canyonlands National Park and vicinity 

during the study period............................................. 42

6. Graph A displays the trends in dispersal distance over three time 

periods. Graph B shows that the average rate of razorback sucker 

movement (km/day) decreases from an initially high rate following 

stocking. Graph C illustrates the average direction that razorback 

suckers traveled. For graph C there is a significant treatment 

affect (p = 0.042)..................................................43

in
EXECUTIVE SUMMARY

Background This document represents the last of a series of reports for an NRPP study 

entitled: Advancing Knowledge on Critical Early Life History and Survival of the 

Endangered Razorback Sucker. Previous reports conducted under this study include: 

Nance. E. 1997. Planktonic and Benthic Invertebrate Densities in Three Backwater 

Habitats on the Lower Green River. Mueller. G. and E. Wick. 1998. Testing of Golf 

Course Ponds at Page, Arizona for Suitability as Grow-Out Facility for Razorback Sucker 

Using Surplus Fish from Ouray National Fish Hatchery. USGS Open-File Report 

98-151. Mueller. G. and P.C. Marsh. 1998. Post-stocking dispersal, habitat use, and 

behavioral acclimation of juvenile razorback suckers (Xyrauchen texanus) in two 

Colorado River reservoirs. USGS Open-File report 98-301.

Thirty razorback suckers from Ouray National Fish Hatchery were fitted with external 

radio transmitters and released in the lower Green River at Millard Bottom. Half the fish 

were released immediately, while the remaining half were held in the canyon's backwater 

with a blocking net for 48 hours. Fish were tracked weekly for a 60-day period. Surveys 

extended from the city of Green River, Utah, and the confluence of the Deloris River 

downstream to Lake Powell.

All fish left the release site and generally headed downstream. Dispersal rates for both 

groups were similar for the first 15 days, averaging 4.6 km/day. Three acclimated 

(experimental) and two released (control) suckers moved upstream (one moves 72 km) 

once they entered the Colorado River. During the 15- to 30-day period, average daily 

movement rates of acclimated fish decreased to 1.1 km/day compared to 3.5 km/day for 

those simply released. Razorback sucker average "directed" movements per day 

(+/- km/day) decreased significantly over time (p = 0.050) and varied significantly 

between treatments (p = 0.042). Control fish required more than 30 days to reduce their 

downstream-directed movements, whereas experimental fish reduced their downstream 

directed movements after 15 days. Ten of 14 control fish entered either Cataract Rapids 

or Lake Powell by day 58, whereas only 2 of 9 experimental fish tracked were detected 

that far downstream. We feel this provides initial evidence that post-stocking acclimation 

may reduce dispersal and that additional research is needed to examine other aspects of 

site-acclimation.

1111
INTRODUCTION

The razorback sucker (Xyrauchen texanus) is an endangered fish native to the Colorado 

River drainage of the Southwestern United States. Records of its capture in Canyonlands 

National Park have been extremely rare, undoubtedly due to the difficulty of sampling 

these remote reaches and possibly due to the rarity of the species. To our knowledge, no 

wild razorbacks have been captured in the past decade (Tom Chart, UDNR, personal 

communique) and only a few fish were taken prior to that period. Minckley et al. (1991) 

reported uncovering reports of only five razorback suckers being taken from Cataract 

Canyon and all were adults (Persons et al. 1982, Valdez et al. 1982, Valdez 1988). 

Holden conducted fish surveys within Canyonlands National Park between 1967- 1972 

and reported razorback suckers were rare and juveniles absent (Holden 1973). Eight 

juveniles were reported captured between Moab and Dead Horse Point prior to Holden's 

effort in 1962-64 (Taba et al. 1965). By all accounts, it appears adults and especially 

juvenile razorback suckers have become extremely rare in the park during the past 4 

decades.

Few extant populations of razorback sucker remain. Those remaining are scattered, 

comprised by very few fish (Tyus and Karp 1990) which experience low or no 

recruitment (Minckley 1983). The largest population occurs in Lake Mojave, 

Arizona/Nevada, with a small population in Lake Mead's Las Vegas Cove, and 

occasional collections downstream from Lake Mojave in the Lower Colorado River and 

its associated canal system (Minckley 1983, Marsh and Minckley 1989). The largest 

remaining population of riverine razorback sucker occurs on the Green River between the 

Yampa and Duchesne Rivers of Northeastern Utah (Tyus 1987, Tyus and Karp 1990). 

Very few naturally-spawned juvenile razorback suckers have been collected in the 

Colorado River drainage in recent history (but see Gutermuth et al. 1994, Marsh and 

Minckley 1989, Modde 1996, Modde et al. 1996), despite adult suckers being collected, 

albeit very rarely. Recently fisheries biologists in Utah, Colorado, Nevada, New Mexico, 

and Arizona have begun razorback sucker stocking programs to compensate for the 

razorback sucker's low rate of recruitment (Burdick and Bonar 1997, Langhorst 1989, 

Pfeifer and Burdick 1998, Ryden and Pfeifer 1995).

Historical efforts to enhance the dwindling populations of razorback suckers hi the lower 

Colorado River (Langhorst 1989, Marsh and Minckley 1989) by stocking hatchery-reared 

larvae and small fish appeared to have failed (Minckley et al. 1991). In 1986, more than 

1.4 million larvae were stocked into the Colorado River from Topock Gorge (just 

downstream from Davis Dam) to near Yuma. The U.S. Fish and Wildlife Service 

(USFWS) was able to capture only 41 juvenile razorback suckers from the original 1.4 

million larvae (Marsh and Minckley 1989). Although the return seemed small, Minckley 

(1995) pointed out that between 1981 and 1989 ~15 million razorback sucker larvae were 

stocked in the lower Colorado River, and if only 0.1% survived, then we should have 

only expected to encounter slightly less than one fish per surface hectare of water.

1
Attempts to reestablish razorback sucker in the Verde and Salt Rivers of Arizona using 

hatchery-reared fish were unsuccessful. Between June 30, 1981, and December 1, 1989, 

10,334,498 razorback suckers <100 mm in total length (TL) and 120,865 between 100 to 

287 mm TL were stocked into the Verde and Salt Rivers and their associated tributaries 

(Hendrickson 1993). Recapture data showed that very few of these razorback suckers 

survived more than 1 year. Those that did survive were found to be in poor condition 

(lost weight) and harbored extremely dense infestations of the parasitic copepod Lernaea 

cyprinacea (Creef and Clarkson 1993). Lernaea is an exotic parasite first known to 

inhabit Arizona waters as early as the 1930s (James 1968). It imbeds itself on the dermal 

surface, predominantly fin bases, of fish and subsequently feeds upon them. Lernaea 

infected fish in the upper Verde River with the highest incidence rate (~54% of all 

catostomids) in Arizona (James 1968). Hendrickson (1993) found that razorback suckers 

infested with Lernaea were more likely to perish when caught in 3-hour trammel net sets 

than were other fish species (zero mortalities, with or without Lernaea) and alluded to 

parasitic loads, predation from exotic fishes, and stress related to transport as factors that 

may have contributed to the low survival rates of stocked razorback suckers.

Current efforts to artificially enhance razorback sucker numbers in Lake Mojave have 

been attempted by placing the larvae into predator-free enclosures and allowing them to 

grow to -250 mm TL before release (Mueller and Burke 1999, Mueller 1995). Between 

1993 and 1995, 640 razorback sucker had been stocked into Lake Mojave in this fashion 

and have yielded 15 recaptures. These 15 fish (28 to 53 cm) represented the largest 

assemblage of young adult razorback suckers collected from Lake Mojave in nearly 

20 years. During the past 5 years, 20,000 additional razorback suckers have been stocked 

and have resulted in over 100 recaptures (Marsh and Pace 1999).

Stocking efforts to enhance razorback populations in the upper Colorado River Basin 

have just recently begun in earnest and have also resulted in low survivorship rates, 

except for perhaps stockings made into the San Juan River (Dale Ryden, FWS, personal 

communique). Twenty razorback suckers were released with 4.5-year radio tags in the 

upper Colorado River [river kilometer (RK) 339.0 to 367.0] during April of 1994 by U.S. 

Fish and Wildlife Service (USFWS) personnel (Burdick and Bonar 1997). These fish 

were all small adults (451 to 534 mm TL) and experienced relatively high post-release 

mortality for fish of this size during the first 150 days (7 of 10 confirmed or presumed 

dead, 10 missing). The same researchers also released 25 similarly sized razorback 

suckers (455 to 535 mm) into the Gunnison River during the same time period. 

Razorback sucker stocked into the Gunnison River also experienced high mortality rates 

during the first 150 days (19 of 22 confirmed or presumed dead, 3 missing).

In October 1994, 24 small adult razorback suckers (325 to 405 mm TL) outfitted with 

radio tags and 656 pit-tagged razorback suckers of similar size (~200 to 440 mm), were 

released into the San Juan River between RK 128 and 219 (Ryden and Pfeifer 1995). The
authors report survival rates of radio-tagged razorback suckers between 40 and 53%. 

Twenty-five of the 656 pit-tagged razorback suckers were recaptured during the first 

6 months. The recapture rate of pit-tagged fish is quite high when considering the large 

size of this study area and may indicate that the San Juan River is an excellent choice for 

future stocking of razorback suckers. However, since growth rates were low during the 

first 6 months following release (mean growth rate = .0105% of total length per Vi year), 

perhaps the aquatic food base available to the razorback sucker in the San Juan River is of 

poor quality or made partially unavailable due to competition with other fishes, the threat 

of predation, or some other factor. Or perhaps the low growth rates indicate that a 

substantial period of time is required for razorback sucker to make the transition from 

hatchery to turbid river.

The survivorship of stocked razorback sucker has been increased by releasing relatively 

large fish (>250 mm) instead of larvae (10 to 20 mm) (Mueller 1995), however, adult 

razorback suckers stocked into rivers undertake large movements during the first weeks 

of liberation and often suffer high mortality. For example, the releases of adult razorback 

sucker made by Ryden and Pfeifer (1995) in the San Juan River, Burdick and Bonar 

(1997) in the upper Colorado and Gunnison Rivers, and Day and Modde (1999) in the 

Green River have shown that stocked razorback sucker will undertake movements 

directed downstream (0 to 80 km) during the first few weeks following their release. This 

directed movement downstream accounted for a combined 46 out of 91 (50.5%) 

razorback suckers departing the two sites targeted for their introduction. Exceedingly few 

suckers (4 of 91) were observed to move upstream from their release points. Downstream 

emigration combined with fatalities (27 fish) have contributed in part to the difficulty in 

creating and maintaining viable, reproducing populations of razorback suckers in the 

habitats deemed to be suitable, as listed in the razorback sucker recovery plan (Tyus 

1998). Researchers have suggested that stocked fish should be ".. .stocked as far 

upstream as possible" (Burdick and Bonar 1997, Ryden and Pfeifer 1996) . This 

suggestion does have merit considering the propensity of razorback suckers to initially 

move downstream from a stocking site, but this technique requires that a great many 

individuals be stocked at a far distant location due to the low probability that a particular 

fish will survive, move downstream a set distance, and become a resident in a targeted 

section of river.

This project assessed movements and habitat use of razorback sucker stocked in the 

Green River, Canyonlands National Park, and tested pre-stocking acclimation as an 

alternative method to "upstream stocking," as suggested by Burdick and Bonar (1997) 

and Day and Modde (1999). The study was directed at determining the practicality of 

reestablishing/augmenting a viable population of razorback sucker into the Green and 

Colorado Rivers within Canyonlands National Park.

Two groups of 15 razorback suckers were compared: an acclimated group held in a 

backwater for ~2 days, and a second group handled identically and placed immediately
into the river adjacent to the backwater. The non-acclimated suckers served as a control. 

We examined if pre-release acclimation was able to affect the dispersal distance, dispersal 

rate, or behavioral patterns of razorback suckers following stocking, as well as examining 

the habitats that razorback suckers utilize within Canyonlands National Park.

MATERIALS AND METHODS 

Sources and Transportation of Fish

Thirty razorback suckers were obtained from the USFWS Ouray fish hatchery located 

near Vernal, Utah. The 30 fish were the progeny of 1 female and 2 males collected from 

the Green River at the Jensen site (River Kilometer[RK] 490; RK 0.0 is the confluence of 

the Green and Colorado Rivers). The suckers were the control group for a canceled 

chemoreception experiment. (Tom Pruitt, USFWS, personal communique).

The razorback suckers were transported in a 2000-L tank with oxygen bubblers from the 

Ouray National Fish Hatchery to the Green River at Mineral Bottom (RK 84) on June 16, 

1998. Fifteen fish were then transferred to 100-L Coleman coolers, lashed inside of a 

5.5-m Achilles inflatable boat. Two transportation trips were made downstream to the 

release point at Millard Bottom backwater (RK 54). Two water changes were made 

during transport to maintain adequate oxygen levels during the 45 minute trip.

Transmitter Attachment

All suckers were measured (TLmm) and weight (g, Appendix 1), and had an Advanced 

Telemetry Systems (ATS©) 90-day radio transmitter attached. Each transmitter was 

verified to be functioning properly before being attached to a fish by removing the 

deactivation magnet and listening for a signal with the ATS receiver. Transmitters were 

5.5 by 1.0 cm, outfitted with a beveled leading edge and a tapered rear cone, and 

attachment holes had been drilled through the epoxy. The holes were placed 1/3 up from 

the bottom on both ends of the transmitter. Transmitters were sewn with 9-kg test 

monofilament line onto the midline of the suckers' dorsal keels directly above the 

pectoral fins. Each suture was inserted ~10 mm below the dorsal keel surface and three 

square knots held each transmitter firmly against the keel. Each transmitter trailed a 25- 

cm whip antenna made of very fine stainless steel wire. The whip antennae terminated 1 

to 10 cm anterior to the upper lobe of the caudal fin. None of the whip antennae needed 

to be trimmed in order to avoid contact with the caudal fin.

This external attachment method was modified from Mueller and Marsh (1998) and was 

designed to allow the fish to eventually "shed" the tag. Experiments in circular tanks 

showed that the monofilament sutures would be pushed to the dorsal keel surface and 

expelled by razorback suckers over time. A few fish shed their transmitter within the first 

month, but most fish retained their transmitters for two or more months. This method is
in sharp contrast to the more widely used technique of surgically implanting radio 

transmitters. This method can lead to substantial fish mortality due to chronic infection 

of the abdominal dermis surrounding the exit hole created by the trailing whip antenna. 

However, some of the new transmitters employ an internal, coiled antenna that eliminates 

the exit hole but also decreases the detection distance. Implanted transmitters will remain 

inside fish for the remainder of their lives, while externally attached transmitters will 

likely be shed soon after the research project is complete.

Immediately following transmitter attachment, fish were alternately assigned to be either 

control or experimental treatment. A block net was placed at the mouth of Millard 

Bottom backwater, and experimental fish were released behind the blocking net and 

confined to the backwater while control fish were placed adjacent to the blocking net on 

the river side. Due to time and boat limitations, transmitters were only attached to 15 

suckers (7 experimental, 8 control) and released on the evening (1815 to 2003 hrs) of 

June 16, while the remaining fish (8 experimental, 7 control) were released the next 

morning (0900 to 1047 hrs). The block net was removed at 0640 hrs on June 19. Thus 

the period of time that the first seven experimental fish spent in the backwater (~ 2.5 

days) was greater than the second group of eight fish (~1.9 days).

Tracking Design and Effort

Razorback sucker positions were recorded using a 40-MHZ ATS© receiver, a whip 

antenna, and a hand-held directional loop antenna. The previously mentioned National 

Park Service 5.5-m Achilles inflatable boat with a 60-hp jet outboard was used 

throughout the summer for surveys. For each fish located, the RK was recorded and 

habitat was described (see next section).

The study site was in Canyonlands National Park, Utah, and extended into the Colorado 

and Green Rivers outside of the park (Figures 1). Twenty-two field surveys were 

conducted between June 24 and August 13 (Table 1). Thirteen of the 22 surveys 

repeatedly surveyed 3 reaches of river that were observed to contain radio-tagged 

razorback sucker. The first of these reaches was Mineral Bottom (RK 81.7) to Spanish 

Bottom on the Green and Colorado Rivers. Spanish Bottom is located 6.4 km below the 

confluence of the Green and Colorado Rivers and lies 0.75 km upstream from the start of 

Cataract Canyon rapids. The Mineral Bottom to Spanish Bottom section was surveyed 

five times (June 24 and 30, July 9, and August 5 and 7). The second reach was Potash 

boat dock (RK 77.1 ) to Spanish Bottom on the Colorado River. Potash to Spanish 

Bottom was also surveyed five times (July 1,8, 13, and 30, and August 13). The third 

reach was on Lake Powell from Hite Marina (RK 270.6) to the base of the Cataract 

Rapids at Imperial Canyon (RK 322). The river kilometer "zero point" below the 

confluence of the Green and Colorado Rivers is at Lee's Ferry; the confluence is 

considered to be RK zero if you are upstream in either the Green or Colorado Rivers, or
Colorado River RK 348.5 if you happen to be downstream of the confluence. This 

section of river/lake was surveyed three times (July 1 and 14, and August 12).

One 3-day survey was made in Cataract Canyon rapids on July 13-15. The remaining 

five surveys were made upstream of Mineral Bottom and Potash Boat dock. These 

surveys included the Green River from RK 81.9 to 218.4 and the Colorado River from 

RK 77.1 to 160.6.

A total of 452.9 km of river was surveyed for study razorback suckers. Throughout this 

section of river, an average sampling effort of one fish was located every two boat-hours. 

Alternatively, a radio-equipped fish was located every 53 km of river. Transmitters that 

were shed or otherwise immobile were not included in the effort estimation.

Habitat Use

Each time a razorback sucker was located, habitat type, surface water velocity, and water 

depth were estimated. Habitat was divided into four categories: channel, near shore, eddy 

pool, and backwater, and described below:

1. Channel - Defined as the deepest, and most often swiftest portion of the river. Both 

the Green and Colorado River channels were typically greater than 3 m in depth and 

surface currents greater than 5 km/hr.

2. Near shore - Defined as river habitat within 10m from shore. If a fish was within 

10 m of shore, but was also determined to be in the main channel or in a eddy, then 

the fish would be considered to be utilizing the alternative habitat type and not be 

considered near shore.

3. Eddy pools - Formed by water returning upstream, typically near shore, which then 

enters back into downward flowing currents. Eddy pools are typically oval in shape 

with the long side parallel to the main channel. Water flows quickly around the 

perimeter of the pool (referred to as an eddy fence), but never as swift as the main 

channel, with very slow moving water found in the middle of the eddy pool.

4. Backwaters - Most of the backwaters that exist in the study reach are naturally 

occurring areas of still water found in flooded canyon mouths. Backwaters are 

typically 15 cm to 1.25 m deep and can wind nearly 0.3 km up a canyon from the 

main river. These regions are devoid of current, are not as turbid as the main river, 

have heavily vegetated banks and margins (dominated by tamarisk, Russian olive, and 

willow), have slightly wanner water, and more productive plankton communities than 

found in their associated river (Mabey 1993). However, these regions are subjected to 

annual drying during the descending phase of the hydrograph, as well as being 

subjected to unpredictable flash floods during the summer monsoon season.
Discrete measurements of water velocity were not made; instead, visual assessments were 

made of the speed of water passing over the position of a located razorback sucker. Swift 

current was defined as being equal to the channel current. Slow current was defined as 

regions of no current or current that was visually estimated to be less than 2 km/hr. The 

category of moderate current was given to current other than swift or slow. The depth of 

the water where a razorback sucker was located was estimated by approaching as close to 

the fish as possible and lowering a 3-in-long, incremented oar into the water until it 

touched bottom or until the entire oar was beneath the surface. Water depth was placed 

into three categories: <1.2, 1.2 to 3, and >3 meters.

Equipment Performance

The ability of the ATS receiver to detect transmitter signals was affected by various 

factors. First, the effective range of the transmitter was more than doubled by efforts to 

eliminate static interference generated by the outboard engine. The receiver was placed 

into a large army-surplus rocket box. Next, the power supply was changed from running 

off of the boat's battery to a small motorcycle battery that was also placed inside of the 

rocket box. And finally, the whip antenna was mounted on the bow so as to maximize its 

distance from the outboard engine. After making these modifications, shallow water 

detections improved from 100 to 250 m to an average of 700 to 1000 m, with maximum 

detection ranges often approaching 1.7 km.

Even with the increase in receiver performance, deep signals >5 m remained difficult to 

detect due to signal attenuation. Razorbacks in the deepest portion of the channel were 

usually detected at less than 300 m. Since the boat was operated at a constant speed of 

-350 m/minute, and the receiver was able to scan all of the tag frequencies in a single 

minute, it was unlikely that many tags were missed during the monitoring. Additionally, 

all surveys were "round-trip," so each portion of surveyed river was scanned for tagged 

razorbacks twice each trip. Very rarely were tagged razorbacks not detected on the initial 

leg and later detected on the return trip.

Data Analysis

The condition factor, a "plumpness" index, was calculated for each razorback sucker 

using the equation K = [weight(grams)* 100]/[length(mm)3]. A regression analysis was 

performed on the condition factors to determine if there was a significant positive or 

negative relationship between K and either length or weight. This analysis was 

performed on Excel '97. Next, a two-tailed t-test was utilized to determine if razorback 

suckers that utilized backwater habitat had significantly different condition factors than 

the suckers that were not observed to utilize backwaters. The t-test was performed on 

Excel '97. Finally, three separate 3-factor ANOVAs were performed to determine if the 

condition factor of a fish would influence its selection of a particular habitat type, current
velocity, or water depth. The other two factors that were analyzed were time and 

treatment (acclimated vs. not-acclimated fish). The analyses were performed on SPSS 

(version 8.0) using the "General Linear Model - General Factorial" model. Type three, 

sums of squares were used and no data transformations were needed to meet the 

assumptions of normality and homogeneity of variances.

The movement patterns of the razorback suckers were analyzed with three 2-factor 

ANOVAs (SPSS version 8.0). The analyses were performed to determine the following 

questions:

1. Was the total distance that razorback suckers traveled since release dependent either 

upon the time since release or treatment?

2. Was the rate of razorback movements (km/day) dependent either upon the time since 

release or treatment?

3. Was the direction of a fish's travel (+/-km/day, + = upstream, - = downstream) 

dependent either upon the time since release or treatment?

Type three, sums of squares were used to compute the F-statistics for the ANOVAs. Data 

used for the total distance ANOVA was not transformed. Average daily movement data 

were log transformed. Data for the directed average daily movements were power 1.5 

transformed. Data still did not meet the assumptions of homogeneity of variance or 

normality, but were modestly improved over non-transformed data (Appendix 3). In 

addition, the transformed data increased the power of the ANOVA models for both 

average daily movements (0.901 -> 0.999) and directed movements (0.829 -> 0.843).

RESULTS 

Individual Movements - Distance From Release Point

All 15 razorback suckers that were placed into the backwater at Millard Bottom (Green 

River RK 54) actively swam within the flooded canyon mouth prior to their eventual 

release. The water in the backwater was turbid, so visual observations of the suckers' 

daily activities were impossible, however, each fish's position within the backwater was 

determined via telemetry on six separate occasions during the acclimation period. The 

backwater had four distinct regions: the inflow (4), the outflow (1), and two interior 

regions (3 and 4) delineated by bends in its channel. Razorback movements within the 

backwater are presented in Table 2. Initially, only 20% (9 of 45 contacts) of the fish were 

positioned next to the blocking net, but during the day before the net was removed 43% 

(16 of 37 contacts) were found near the blocking net.

Two fish escaped during this period of acclimation (Table 2). This occurred after heavy

8
rains on June 17 caused the Green River to rise and create a ~2-m-wide passage around 

the western edge of the blocking net. This escape route was less than 50 cm deep and 

contained a dense stand of juvenile willows. The willows possibly aided in reducing the 

total number offish that escaped.

The blocking net was removed at 0640 on June 19. The departure of the remaining 

13 experimental treatment razorback suckers (acclimated fish - referred to as "E" for - 

experimental treatment) from the now river-accessible Millard backwater was monitored 

until 0912. The first razorback sucker to leave the backwater was 12E at 0805. This fish 

headed downstream, was out of the ~l/2-km receiver range in 7 minutes, and was never 

contacted again. Razorback sucker 14E exited next at 0841 and was followed by sucker 

5E at 0846. Fish 14E headed downstream, was out of range in 18 minutes, and was never 

contacted again. Fish 5E departed downstream, moved out of range in 26 minutes, and 

would travel downstream to the Colorado River (54 km distance) and then swim at least 

72 km up the Colorado River over the next 20 days.

The movements of razorback suckers during the first day following their release were 

only determined for the control group (non-acclimated fish - referred to as "C" for 

control treatment) due to logistical difficulties. On June 17, five control fish (1C, 2C, 4C, 

6C, and 14C) were located in or near Andersen Bottom (Green River RM 48.9), and the 

search was terminated at Green River RK 47. Fish 1C, 2C, and 4C were all located 

within Anderson backwater. Fish 14C was located in the inside bend of the main channel 

of the Green River opposite Anderson Bottom, and sucker 6C was 1 km down river of 

Anderson Bottom in the river left portion of the main channel and moving downstream. 

Only fish 14C was released this same day (June 17, 7.8 hours earlier), whereas the 

remaining four fish were released the previous day (June 16,23 hours earlier). It is 

inexplicable that the majority of the fish located within 7 km downstream from the 

release point were released the previous day and not fish released just 7.8 hours prior. 

Fish 1C, 2C, and 6C were located in different backwaters further downstream 7 days 

later. It would appear that control razorback suckers seek and enter backwaters as they 

move downstream following release.

Both the experimental and control razorback suckers initially moved downstream from 

the release point during the first 2 weeks. After this initial period of downstream 

movement, a few fish (IE, 5E, 8E, 15E, 2C, and 7C) that had reached the confluence of 

the Green and Colorado Rivers (53.8 km distant) began to swim up the Colorado River 

(Figures 2A, 2B, and 2C). By day 25, fish 8E was now located 8.8 km up the Colorado 

River from its confluence with the Green River and was not contacted again.

Razorback sucker IE moved downstream to the Colorado River and swam 52 km 

upstream during the first 12 days. By day 54, razorback IE had moved down the 

Colorado River, swam through Cataract Canyon rapids, and was now positioned in Lake
Powell adjacent to the mouth of Gypsum Canyon some 85 km downstream.

Fish 5E reached the confluence in no longer than 7.8 days and, as previously mentioned, 

swam up the Colorado River at least 72 km. Between 19 and 24 days after its release, 5E 

began to move downstream and was last contacted 4.8 km above the Green River 

confluence.

Razorback sucker 15E was the only fish observed to move upstream in the Green River 

during the course of the 58-day study. Initially, 15E moved downstream to Green River 

RK 29.1 by day 11.4. During the next 9 days, 15E moved 2.5 km upstream. During 

days 20 to 47, razorback 15E then moved upstream again and was last contacted day 49 

at Green River RK 41.4 12 km below the release point.

Razorback 2C reached the confluence and traveled at least 24.9 km up the Colorado River 

during the initial 14 days. During the next 13 days, 2C moved 30.5 km downstream to 

6 km below the Green River confluence. This position was ~0.9 km above the first 

Cataract Canyon rapid. Later this same day, at 1733 (day 27.9), 2C had moved into 

Cataract Canyon rapids and was in the large, swift, eddy pool circulating below rapid #2 

(Colorado River km 340.2, confluence = RK ~348.5). By the following afternoon at 

1622, fish 2C had completed its journey through Cataract Canyon rapids and was located 

~0.5 km above Imperial Canyon (Colorado River RK 322.3). Fish 2C was able to move 

through the ~21 km of rapids in 1.05 days. By day 56, fish 2C's last known position was 

just inside the mouth of Clearwater Canyon in Lake Powell (Colorado River RK 308.2).

By day 14, razorback 7C had departed the Green River and swam 10.8 km up the 

Colorado River. During the next 7 days, 7C moved downstream and to the mixing zone 

of the Green and Colorado River confluence. From this time until day 58, razorback 7C 

positioned itself at Colorado River RK 345.2 and moved about within a 200-m section of 

river. This razorback sucker was observed to still be mobile by its periodically moving 

out from the deep channel (faint tag signal) and swimming along the shoreline (strong tag 

signal).

The remaining razorback suckers were either lost from contact early on, or moved 

downstream to the Colorado River and positioned themselves between the confluence and 

the head of Cataract Canyon Rapids (a reach of ~7 km), or they continued downstream 

and entered Lake Powell where contact was generally lost. Razorback suckers 3E, 10E, 

1C, and 9C were all located only once or twice. These four fish were moving 

downstream and it is unknown whether they later entered Lake Powell, or remained in the 

Green or Colorado Rivers and avoided detection by seeking out the deepest portions of 

the river. The radio-tag signals may attenuate to below detection levels when ~9 or more 

meters deep. Fish 6E, 8E, 14E, 5C, and 11C rapidly moved downstream and out of the 

lower 52 km of the Green River and positioned themselves in the previously mentioned 

Colorado River reach above Cataract Canyon rapids and the Green River confluence.

10
The remaining fish (2E, 3C, 6C, 8C, 12C, 13C, 14C, and 15C) all moved continuously 

downstream and entered Lake Powell.

Individual Movements - Estimated Rates of Movements

Only 17 of the 23 razorback suckers that were located following their release were 

contacted a sufficient number of times to estimate their daily rates (km/day) of movement 

(Figures 3A and 3B). Six razorback suckers (10E, 1C, 3C, 4C, 11C, and 14C) were 

located just twice during the 58 days of tracking. The remaining 11 fish were contacted 

between 3 and 7 times. The general trend was for the initial movement offish to be at a 

high rate of ~5 km/day and decrease over time to near 0 km/day.

However three razorback suckers increased their estimated daily rate of movement over 

time. Fish 10E and 1C increased their daily movements from ~3 km/day during the first 

few days following release to ~5 km/day by day 10. Contact was lost with both fish by 

day 12, so it will remain unknown if their rate of movement attenuated over time as 

occurred in the majority of the razorback suckers. Fish 2C, the third razorback sucker to 

have an increased daily movement rate over time, decreased its daily movements from 

~5 km/day during days 1 to 8 to near 0 km/day during days 30 to 58. However, a burst of 

movement occurring during day 29 resulted in a positive slope (Figure 3B).

The direction of the estimated daily movement rates for the suckers can also be seen in 

Figures 3 A and 3B. Positive data points designate upstream movements, whereas 

negative data points designate downstream movements. Only two suckers with greater 

than two contacts increased their rate of downstream movement over time. As previously 

mentioned, fish 2C moved down the Green River and then up the Colorado River 

24.9 km. Fish 2C then began a fairly rapid movement downstream and entered Lake 

Powell. This rapid, mid-study, downstream movement resulted in a negative slope for 

2C's average directed rate of movement over the course of the study period. Fish 5E also 

increased its rate of downstream movement over time. Fish 5E moved out of the Green 

River in approximately 8 days traveling at ~8 km/day (Appendix 1). Fish 5E then made a 

55.8-km movement up the Colorado River between days 7 and 12 at ~12 km/day. 

Upstream movement continued at a reduced rate (~3 km/day) until day 19, at which point 

5E moved downstream at ~-7 km/day and contact was lost 4.8 km above the Green River 

confluence. This trend in daily movements from large upstream, to small upstream, to 

large downstream resulted in the trend of 5E increasing downstream movements over 

time.

Individual Movements - Fish Condition Factor (K)

The movement patterns of razorback suckers did not appear to be dependent upon the 

condition factor [K = (weight* 100/length3)]. Condition factors (K) ranged between 0.734 

and 1.057, and were not correlated with length (p = 0.97, regression analysis) but were

11
positively correlated with weight (p = 0.02, regression analysis, Figure 4). Appendix 3 

summarize aspects of the suckers' movements in conjunction with their condition factors. 

The condition factors of the experimental and control fish that were observed to either 

swim upstream or hold position in the river overlapped broadly with the condition factors 

of the fish that were observed to only move downstream. The 7 razorback suckers that 

were never contacted following release had similar condition factors to the 23 fish that 

were located via telemetry. In addition, the condition factors (average K = 0.845, n = 6) 

of the six razorback suckers that utilized backwater habitats were not significantly 

different from the condition factors (average K = 0.892, n = 14) of those fish not observed 

to utilize backwaters (p = 0.22, two-tailed t-test).

Individual Habitat Use and the Effects of Condition Factor

During the first 2 weeks since release, the razorback suckers distributed themselves 

throughout many of the available habitat types (Table 3). Many fish moved between 

multiple habitats during this time period. For example, fish 6C was positioned near shore 

and moving rapidly downstream at Green River RK 48 on day 1. Fish 6C then entered 

Horse Canyon backwater (Green River RK 23) by day 7, remained there until at least 

day 13 as the water level fell to an estimated <60 cm, and then re-entered the main 

channel sometime before day 22. Fish 2C, 7C, and 3E also moved between habitats 

during the first 14 days. Fish 2C utilized both near shore and main channel habitat, as 

well as venturing into Jasper Canyon backwater (Green River RK 15.3) on day 7. Both 

7C and 3E were located in near shore, eddy pool, and channel habitats as they continued 

to move downstream.

During the 15 to 29 day period following release, the majority offish now began to 

generally utilize a single type of habitat. Only two fish, 5E and 8E, were observed to be 

utilizing two or more habitat types. Fish 5E was located near shore at Colorado River 

km 71.9 on day 19 and then entered the channel and quickly moved downstream to 

Colorado River RK 4.8 by day 25. Fish 8E was located near shore in a deep run adjacent 

to the large cottonwood tree at Spanish Bottom (Colorado River RK 342, Green River 

confluence = RK-348.5). Later, 8E was moved upstream to the large eddy pool in the 

tailwater of "The Slide" at Colorado River RK 2.4.

During the last 4 weeks of the study (days 30 to 58), the majority of razorback suckers 

were no longer near shore, but rather were split between near shore (five fish) and 

channel habitat (five fish). At this point, the water level of the Green and Colorado 

Rivers is sufficiently low to have dried all of the backwaters that have formed at the 

mouth of ephemeral canyon inflows (Figure 5). Eddy pools were now the least utilized of 

the available habitats. Only fish 6E and 7C were now observed to be positioned in eddy 

pools. However, both 6E and 7C were now found in eddy pools only once during this 

period while being found near shore twice (6E) and in the main channel four times (7C).

12
Four different control fish and two experimental treatment fish were observed to occupy 

backwater habitat in the Green River below the release site. Fish 1C was observed in two 

separate backwaters (Anderson Bottom and at Green River RK 12) and fish 6C was 

located in Horse Canyon backwater (Green River RK 23.3) on three separate occasions. 

Backwaters were only utilized by the control fish during the first 2 weeks. Fish 15E was 

the only sucker observed to still utilize backwater habitat after 2 weeks (July 9, day 20). 

FishlSE was located in Dead Horse Canyon (Green River RK 31.5 ), which was rapidly 

becoming dry. This fish did not need rescued, however, because a flash flood carried 15E 

into the river shortly after day 20.

Between the 0 to 14 day period following release, razorback suckers utilized riverine 

habitats which experienced all available current intensities, but the majority offish 

locations were in regions of slow or no current (Table 4). In spite of a high affinity for 

slow current, many razorback suckers (5E, 10E, 14E, 15E, 2C, 5C, 6C, and 7C) moved 

between regions of slow current (<~1.4 km/hr) and swift current (>~3.8 km/hr). Fish 6E, 

8E, 1C, 14C, and 15C were observed to only utilize habitats with slow or no current. 

Fish 6E, 14C, and 15C were located in near shore regions; 1C was found in Anderson 

backwater (Green River RK 49.8) on day 1 and in a shallow backwater at Green River 

RK 12 on day 7; and 8E was in a slow moving eddy pool at Colorado River RK 342. 

Sucker 9C was the only fish that utilized solely regions of swift water. Fish 9C was 

located in different sections of swift water on three separate occasions during these first 

15 days.

During the period of 15 to 29 days since release, 12 of 15 razorback suckers were found 

to be in habitats of slow or no current. Fish 11C, 15C, and 5E were positioned in slow 

current, as well as occupying moderate current (11C and 15C, -1.4-4.6 km/hr) and swift 

current (5E).

During the final 4 weeks the suckers began to reoccupy habitats with swift current, as 

well as continuing to utilize slow current regions. Only 7C moved between habitats in 

different current categories. Fish 7C occupied the very deep, swiftly flowing water in the 

run adjacent to and upstream from the "Dangerous Rapids Ahead" sign at Colorado River 

RK 345. As previously mentioned, fish 7C was also observed on one occasion to move 

out of the channel and move upstream along the northwestern bank approximately 100 m.

Razorback suckers initially began to occupy habitats of seemingly every available depth 

(Table 5). During the first 14 days, the experimental fish were utilizing chiefly shallow 

(0-1.2 m) or deep water. Only one fish from the experimental treatment (15E) was 

located in a habitat of moderate depth (1.2 to 3.0 m). Fish 15E was also found in the 

shallowest backwater habitats and the deep main channel. The control treatment fish 

were found in similar proportions in shallow, moderate, and deep habitats. Three control 

fish (2C, 6C, and 7C) were observed to move between shallow and deep regions of the 

Green and Colorado Rivers.

13
During the 15 to 29 day period since release, razorback suckers were not observed to 

move between habitats of different depths as often as during the first 2 weeks. Only fish 

5E and 8E were observed to utilize both shallow and deep habitats. Fish 5E utilized both 

near shore and eddy pool habitats while 8E utilized near shore and channel habitats.

During the final 4 weeks of the study (30 to 58 days), razorback suckers utilized 

predominantly deep-water habitats. Fish 6E was observed utilizing all three depth 

categories, 15E utilized moderate and deep water habitats, and the remaining fish (8E, 

14E, 2C, 7C, and 11C) were utilizing habitats greater than 3 m deep. Fish IE and 15C 

were found in >3-m-deep water in Lake Powell.

Tables 6, 7, and 8 summarize the condition factors of the fish that were located in each 

habitat, current, and depth category, respectively, over time. The average condition 

factors of the fish that frequented the four habitat types during the three time periods 

ranged from 0.81 to 0.93 and were not dependent upon habitat type (p = 0.610), treatment 

(p = 0.766), or time (p = 0.404). The average condition factors of the fish that occupied 

the three current intensities ranged from 0.771 to 0.966 and were not dependent upon 

current velocity (p = 0.935), treatment (p = 0.072), or time (p = 0.070). However, it 

appears that fish with large condition factors disproportionately utilized habitats of 

moderate depth (average K = 0.922) to a greater extent than either shallow habitats 

(average K = 0.869, p < 0.001 rukey's post-hoc) or deep habitats (average K = 0.874, p = 

0.018 tukey's post hoc).

Comparison of Treatments: Movement Patterns and Habitat Use

The majority of razorback sucker dispersal away from Millard Canyon backwater 

occurred during the first 2 weeks for both treatment groups (Figure 6A). There was no 

significant affect of treatment (p = 0.737) or time (p = 0.120) upon the distance fish 

traveled from the point of release. However, there was a small but steady increase in the 

distance control fish traveled over time. Control fish dispersed 43, 71, and 81 km for the 

time periods 1 to 14 day, 15 to 29 days and 30 to 58 days following release. 

Experimental fish averaged 59 km distance traveled over the first 14 days, this increased 

to 71.6 km by days 15 to 29, and reduced to 53.6 km by the end of the study. Although 

differences in dispersal were very similar, a greater proportion of control razorback 

suckers traveled downstream upon reaching the Colorado River than did experimental 

suckers. Ten of 14 control fish entered either Cataract Rapids or Lake Powell by day 58, 

whereas only 2 of 9 experimental fish were found that far downstream (Appendix 3).

The average distance razorback suckers moved per day (as estimated from successive 

radio contacts) decreased significantly over time (p O.OOO), and was not significantly 

affected by treatment (p = 0.437) (Figure 6B). The average daily movements (km/day) of 

both the experimental and control fish decreased incrementally over time, but at different

14
rates. Experimental razorback suckers slowed their movements to 1.1 km/day after 15 

days and remained similarly mobile (1.2 km) through day 58. Control fish were more 

than twice as mobile 15 to 29 days after release than the experimental fish, but reduced 

their overall movements to a much lower rate (0.37 km) than the experimental fish by the 

end of the study. The reason that the experimental suckers were more mobile during the 

30 to 58 day period was in part due to fish 15E traveling upstream toward the release site.

The difference in the daily movement rates (km/day) between the experimental and 

control fish during the 15 to 29 day period becomes more profound when viewed in 

conjunction with the direction of travel of each fish (Figure 6C). For the purposes of 

addressing the direction of travel of a fish, the movement rates (km/day) have been 

defined as positive if fish are swimming upstream and negative if a fish is traveling 

downstream. Razorback sucker average "directed" movements per day (+/- km/day) 

became significantly less negative over time (p = 0.05) and varied significantly between 

treatments (p = 0.042). As seen in Figure 7C, control fish required more than 30 days to 

reduce their downstream-directed movements, whereas experimental fish reduced their 

downstream directed movements after 15 days.

DISCUSSION 

Dispersal Patterns

Razorback sucker movements within the Millard Bottom acclimation backwater varied 

between individuals and changed in pattern over time. Three of the 15 fish were 

observed to roam nearly the entire length (-1/3 km) of the backwater within 10 minutes, 

while others appeared to roam within limited sections of the backwater or not move at all. 

Patterns in fish movement within this backwater were not correlated with condition 

factor, nor were these patterns able to predict post-release movement patterns. However, 

razorback suckers altered their movement patterns within the backwater over time. Fewer 

suckers (20%, n = 45 contacts) were observed to be positioned near the blocking net at 

the mouth of the backwater during the first day, but by the second day of confinement 

within the backwater the percentage rose to 43%(n = 37).

Only 3 of the 13 suckers (2 escaped) exited the cove within 2 hours of removing the 

blocking net. The three fish departed singly and moved downstream and out of the 

~l/2-km directional receiver range within 7 to 26 minutes. Seven of the ten remaining 

razorback suckers were observed to approach the area where the blocking net had 

previously been only to turn around and swim back into the backwater. These fish either 

simply anticipated that the net would be in its previous location since the turbidity of the 

water prevented visual recognition of the net except at very close range, or they were not 

yet ready or willing to enter the river. The duration of time required for the last razorback

15
sucker to depart the backwater remains unknown, but all the fish had departed the 

backwater within 5 days (the number of days until the next sampling occurred).

One short telemetry survey was made on June 17 to determine the locations of the 30 

control (not-acclimated) fish that were released on June 16 and 17. Five razorback 

suckers were located approximately 5 km below the release site. Three of these fish had 

entered Anderson Bottom backwater, which is the first backwater downstream of the 

release point. Three of these five control fish were later located in backwaters further 

downstream 5 days later. Twenty-nine percent (4 of 14) of control razorback suckers 

were observed to utilize backwaters during the first 2 weeks, two fish at least twice. 

However, since sampling occurred on just 3 days during the first 2 weeks, the actual 

number of control suckers that utilized backwater habitats was probably larger. Stocked, 

non-acclimated razorback suckers seek and enter backwaters as they move downstream 

following release. This rate of backwater use by stocked razorback sucker is much higher 

than that observed by Ryden and Pfeifer (1995) in 1994 and 1995 on the San Juan River, 

but is similar to the rates of backwater use seen in wild razorback suckers in the Colorado 

(18% of contacts) and Gunnison (26% of contacts) Rivers (Burdick and Bonar 1997).

Fourteen of the 15 control razorback suckers were found following release and all had 

moved downstream. Only one control group razorback sucker was not located, and since 

no fish were found on June 19 in the 28 km of river above Millard Bottom, it is very 

likely that all 15 control razorback suckers moved downstream following release. 

The majority of dispersal occurred during the first 2 weeks for both the control and 

experimental treatment groups (Figure 6.) By day 14, the mean maximum dispersal of 

the experimental fish was actually further than the control fish (59 vs.43 km). The 

dispersal distance of the control fish is probably an underestimate because two control 

fish that were located ~5 km from the release point on day 1 were never located again, 

and if they behaved similarly to the other 12 control fish, they would have continued to 

move downstream. By day 29, the mean maximum dispersal distance increased to 

approximately 71 km. During the final period of the study, days 30 to 58, the control 

razorbacks continued to increase their dispersal distance to 81 km while the experimental 

razorbacks decreased their average dispersal distance to 53 km. Although differences in 

dispersal were similar, a greater proportion of control razorback suckers traveled 

downstream upon reaching the Colorado River than did experimental suckers. Ten of 

14 control fish entered either Cataract Rapids or Lake Powell by day 58, whereas only

2 of 9 experimental fish were found that far downstream. However, due to large 

variability between individual fish and a low sample size, these modest treatment (p = 

0.74) and time period (p = 0.12) effects were not statistically significant. Similar 

dispersal distances for both hatchery- and pond-reared razorback suckers stocked into 

rivers were observed in the San Juan River during 1994 (-62.3 km) and 1995 (-95.5 km) 

(Ryden and Pfeifer 1995) and in the Green River during 1995 (week-1 = -39.2km, week3 = -87.1 km) (Day and Modde 1999).

16
The average rate of dispersal for both groups of razorback suckers was very similar 

during the first 14 days, but differed markedly over time. Initial movement rates were 

-4.6 km/day for both treatments. During the 15 to 29 day period, average daily 

movement rates for experimental razorback suckers decreased to 1.1 km/day while 

control suckers decreased their movement rates much less (3.5 km/day). During the 30- 

to 58-day period since release, experimental suckers continued to move at approximately 

the same rate (1.2 km/day) while the control fish had decreased their movements to 

0.37 km/day. Razorback sucker movement rates decreased significantly over time 

(p < 0.001), but due to high within-group variation the observed treatment affect was not 

significant (p = 0.44). This attenuation in the estimated rates of daily movement are very 

similar to those observed by Day and Modde (1999) in 1995 on the Green River. Their 

much smaller razorback suckers (average TL 197.9 mm vs. 437.6 mm) averaged 

6.8 km/day (n = 16) during the first 13 days and decreased to 2.0 km/day (n = 7) between 

days 13 and 28.

Although the rates of dispersal of experimental and control suckers did not differ 

significantly over time, the average directed rates of movement (+/-km/day) were 

significantly different between treatments (p = 0.042). Directed rates of movement were 

calculated for a particular fish by defining upstream movement rates as +km/day and 

downstream movements rates as -km/day and then summing these within treatment and 

time periods. The effect of a 2-day acclimation was to significantly reduce the 

downstream directed movements rates of razorback suckers, as seen in Figure 6. Initial 

downstream directed movement rates of control fish were -4.2 km/day. This is more than 

double the rate (-1.9 km/day) for experimental razorbacks. During days 15 to 29, 

experimental razorback sucker directed movement rates had attenuated to just 0.3 km/day 

while control fish were still continuing to move downstream at a rate of 3.5 km/day. 

Control razorback suckers required at least 30 days from the time of release to reduce 

their downstream directed movements to a level that was reached by experimental 

razorbacks after 15 days.

The finding that the majority of dispersal of stocked razorback sucker occurs during the 

first few weeks following release has been observed in previous razorback sucker 

stockings (Brooks 1985, Day and Modde 1999, Marsh 1987, Mueller and Marsh 1998, 

Ryden and Pfeifer 1995), as well as in other species offish. Chilton and Poarch (1997) 

observed that 50% of the total yearly movements of grass carp stocked into Texas 

reservoirs occurred during the first 2 weeks. Hanson and Margenau (1992) observed that 

the majority of young of the year muskellunge dispersal in lakes occurs during the first 

2 weeks. Carlstein and Eriksson (1996) observed that 75% European grayling 

(Thymallus thymallus) stocked into an experimental stream dispersed greater than 400 m 

downstream during the initial 8 hours.

17
Habitat Use

Razorback suckers in both treatments utilized all available habitats, current intensities, 

and water depths during the first 2 weeks and altered their patterns of habitat use over 

time. However, the two treatments differed in their habitat utilization patterns. Initially, 

the majority of control suckers were located in shallow (<1.2 m) regions with slow 

current (<1.4 km/hr), while experimental fish were most often observed to utilize deep 

water (>3 m) that was either slow or swiftly flowing (>4.8 km/hr). Nine of 19 razorbacks 

were utilizing channel habitat during the first 14 days. During the 15 to 29 day period 

following release, both treatment groups were occupying slow, near-shore habitats and 

deep eddy pools. Only one razorback sucker was observed to utilize channel habitat 

during this period. This experimental treatment fish had moved 72 km up the Colorado 

River and was returning downstream towards the Green River confluence by way of the 

main channel. During the 30 to 58 day period since release, seven of the ten fish that 

could still be located were found in deep water (>3 m), and five fish were now utilizing 

channel habitat. Three of the razorbacks utilizing water greater than 3 m deep were 

located near flooded canyon mouths (2) or moving down lake (1) in Lake Powell.

The pattern of razorback sucker habitat use during the initial 14 days was similar to that 

observed by Burdick and Bonar (1997) in wild razorback sucker in the Gunnison River. 

The pattern of habitat utilization was proportionally 21% (60%) channel, 21% (19%) 

eddy pool, 21% (26%) backwater, and 37% (7%) near shore [parenthesis denote data 

taken from Burdick and Bonar (1997)]. The most obvious difference in the habitat 

utilization rates is that instead of utilizing mainly channel habitat, the razorback suckers 

in this study were found most often near shore as opposed to the channel.

However, this pattern changed during the 30 to 58 day period. During the last 4 weeks of 

the project, the majority of razorback sucker contacts (52%) were now in the main 

channel, 37% were still in near shore habitat, and 11% of contacts were in eddy pools. 

These results contrast with the 1994 and 1995 San Juan stockings in which razorback 

sucker utilized chiefly channel habitat (Ryden and Pfeifer 1996). However, Ryden and 

Pfeifer (1996) observed that razorback suckers show seasonal variability in habitat 

utilization patterns. Perhaps the razorback suckers in both this experiment, as well as 

those of Ryden and Pfeifer (1996), were utilizing deep channel habitat in August, not 

only because it was the most abundant habitat type (~75% of all habitats in the San Juan 

River), but perhaps in order to seek out a preferred temperature as well. Bulkey and 

Pimentel (1983) utilized electronic shuttle box experiments to deduce that razorback 

suckers' preferred temperature lies between 22.9 and 24.8 °C. The thermal profile of the 

Green River within Canyonlands National Park during August of 1998 is unfortunately 

unknown.

A surprising finding was a significant correlation between the condition factor of a fish 

and the depth of water that it utilized. Razorback suckers that utilized habitats of

18
moderate depths (1.2 to 3 m) had on average larger condition factors than fish that 

utilized either shallow (<1.2 m) or deep (>3.0 m) habitats. The reason for this affect of 

condition factor upon depth selection is unclear, but there are at least three possibilities.

First, fish with large condition factors may be more "plump" than their kin because they 

are more efficient foragers. If this is the case, then it follows that Green River habitats of 

moderate depth should be more productive than either deep or shallow zones. It is not 

known if this true. However, this hypothesis is testable since the diet of razorback 

suckers is known to consist of benthic insects, such as Ephemeroptera and Chironomidae, 

algae, detritus, and other items such as Cladocerans in reservoirs (Banks 1964, Jonez and 

Sumnerl954, and Vanicek 1967), and the availability of these items could easily be 

compared at these water depths.

A second explanation is that habitats of moderate depth may require fish to expend either 

greater or lesser quantities of energy to maintain position than either shallow or deep 

habitats. This does not seem to be a correct statement since there was no correlation 

between condition factor and current velocity. In addition, the condition factors offish 

observed to utilize backwaters were not statistically different from the condition factors 

offish found in eddy pools, near shore, or in the main channel.

A third explanation is that habitats of moderate depth are more competitive environments 

for razorback sucker than either shallow or deep habitats, and high condition factor fish 

have an advantage over low condition factor fish when involved in competitive 

interactions. This argument does have some merit in that Abbot et al. (1985) found that a 

weight advantage of only 5% was enough to ensure dominant status during paired intraspecific competition in steelhead trout, and that the razorback suckers used in this project 

had condition factors that were positively correlated with length. It then follows that a 

larger fish involved in inter-specific competition for a food item, current refuge, space, 

etc., would fair better than a smaller or thinner fish.

A Potential Explanation for the Large Initial Dispersal of Stocked Fish

Often fisheries biologists attribute the high initial dispersal rates of stocked fish to 

transport and handling stresses (Bonga 1997, Salonius and Iwama 1993, Waring et al. 

1996). These stresses have been shown to cause fish to respond by secreting higher the 

resting levels of the hormone cortisol (Barton and Zitzow 1995, Clearwater and 

Pankhurst 1997, Pankhurst and Dedual 1994, Wallin and Van den Avyle), which can 

have major physiological consequences. Higher than normal circulating cortisol levels 

cause fat stores to be mobilized (Waring et al. 1996), circulating lymphocyte levels to 

decrease (Barton and Zitzow 1995, and Salonius and Iwama 1993), osmoregulatory 

imbalances (Bonga 1997, Barton and Zitzow 1995), and even lead to follicular atresia 

(Clearwater and Pankhurst 1997). Chronic stresses such as overcrowding or intraspecific competition for resources can result in submissive behavior and the loss of access

19
to preferred habitats, as well as higher rates of mortality (Pottinger and Pickering 1992) 

and decreased fitness (Pankhurst and Dedual 1994).

Clearly, fisheries biologists agree that efforts to minimize handling and transport stresses 

generated during fish stocking is a worthwhile endeavor. The attachment of telemetry 

transmitters requires surgery or attachment with anchors or sutures and can be very 

stressful to the animal. Morton et al. (1995) determined that 17 of 18 species of African 

mammals captured by physical restraint increased plasma cortisol concentrations as 

compared to normal, whereas capture using chemical sedatives usually caused a decrease 

in cortisol levels. These findings illustrate the importance of employing MS-222 sedative 

when outfitting fish with telemetry transmitters.

However, stressors to stocked fish do not ameliorate following stocking. Naive 

hatchery-reared fish will undoubtedly find that making the transition from hatchery pond 

or raceway to turbid, swift rivers is a very stressful event. Stocked fish must learn to feed 

upon natural food sources quickly, learn to identify and escape from predators, and 

navigate lotic environments. Razorback suckers typically move long distances 

downstream during the initial period following stocking, as well as experience reduction 

in growth rates and condition factors (Hendrickson 1993, Ryden and Pfeifer 1995). 

Based on our findings, it appears that this transition period is at least 2 weeks long.

This experiment has shown that pre-stocking acclimation is able to significantly alter the 

dispersal rates of liberated razorback suckers, however a longer period of acclimation 

appears to be needed for razorback suckers to remain near the release site. Perhaps a 2- to 

4-week acclimation period is needed for razorback suckers to acclimate to their new 

surroundings. This is based on experiments by Pottinger and Pickering (1992) that 

showed that between 2 and 4 weeks is required for chronically confined (crowding and 

intra-specific competition stresses) rainbow trout cortisol levels to decrease to those of 

the controls.

CONCLUSIONS AND RECOMMENDATIONS

The collection of razorback sucker larvae from Middle Stillwater Canyon in 1993-1996 

from the lower Green River (Muth et al. 1998) stimulated interest in this river section 

(USFWS 1999). Unfortunately, the backwaters where larvae are typically collected are 

ephemeral, flooding each spring for a few weeks before they drain with receding flood 

flows. It's doubtful larvae gain any appreciable growth before either being forced back 

to the main channel or stranded by receding flows. While nursery habitat is sparse, 

historically, these river reaches must have been important migration corridors. However, 

the apparent absence of both adults and juveniles may suggest these river reaches might 

be only marginally important to the species today.

Stocking within the boundaries of Canyonlands National Park is certainly a management

20
or recovery option; however, we feel the likelihood of establishing local populations in 

themselves is probably unlikely. Cataract Canyon appears to represent a downstream 

conveyance vortex to newly stocked hatchery fish and possibly a hindrance for upstream 

migration. The reestablishment of razorback sucker within the park will probably be 

dependent upon reestablishing or expanding populations elsewhere.

It's well known that hatchery produced razorback suckers are extremely susceptible to 

downstream drift (Ryden and Pfeifer 1996, Burdick and Bonar 1996, Day and Modde 

1999). As with this study, the majority of suckers stocked at Millard Bottom ended up in 

Lake Powell. Current methods to compensate for this drift involves stocking fish further 

upstream of targeted reintroduction sites or as this study suggested, fish should be siteacclimated to reduce post-stocking trauma and possibly subjected to flow prior to 

stocking in riverine environments.

Possible options for reintroducing razorback sucker to Canyonland National Park include:

In-Park. Fish should be stocked during spring run-off and held in seasonally flooded 

backwaters for a minimum of 2 weeks. Backwaters could be effectively blocked with 

barrier nets. We also suggest tests be conducted with acclimating suckers to flow 

(O.lm/sec) for a minimum of 1 month prior to introduction.

Artificial backwater or holding facilities could be constructed in the upper reaches of the 

Green and Colorado River. These semi-permanent structures could be used to rear wild 

caught razorback sucker larvae for eventual reintroduction, or be used to rear and 

acclimate hatchery production to local conditions.

Out-of-Park. As discussed in the report, razorback suckers could be stocked, held, and 

acclimated at upstream locations. Several possible locations exist. Another option would 

be to stock adults or large juveniles in the Colorado River inflow area of Lake Powell. 

It's been documented that razorback suckers stocked in the San Juan River inflow area 

have migrated as far as 80 km upstream (Dale Ryden, USFWS personal communique) 

and similar upstream migrations from reservoirs exceeding 100 km have been noted 

(Mueller unpublished data).

ACKNOWLEDGMENTS

Special appreciation goes to Ed Wick who developed the research theme and initiated the 

NRPP process; Bruce Rodgers and Craig Hauke (NPS) provided study guidance; the 

Canyonlands Park Ranger staff provided logistical support; Tom Czapla and Tom Pruitt 

(USFWS) provided study fish; Johnny Boutwell and David Mueller assisted in the field; 

and the manuscript was reviewed by Tim Modde. Work was conducted under permits 

issued by FWS, NPS, and Utah Division of Natural Resources and funded by USGS and 

NPS.

21
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the Turbot. Journal of Fish Biology 48:161-173.

26
TABLES

Table 1. A summary of telemetry sampling dates, locations, and total river kilometers 

scanned for tags. The information given below the table summarizes the surveying 

efforts.

Description

Short effort to locate control fish below release point

Millard Bottom to Mineral Bottom

Mineral Bottom to confluence

Mineral Bottom to Spanish Bottom

Potash to Spanish Bottom

Hite Marina to Imperial Canyon (base of Cataract Rapids)

Potash to Spanish Bottom

Mineral Bottom to Spanish Bottom

Ranger's snout boat - Potash to river kilometer 29.9

Ranger's snout boat - river kilometer 29.9 to 336

Ranger's snout boat - river kilometer 336 to 302

Potash to Moab boat dock

Moab to top of Big Bend Rapids

Moab to confluence of the Delores and Colorado Rivers

Town of Green River upstream to diversion dam

Town of Green River to river mile 70

Potash to Spanish Bottom

Mineral Bottom to Spanish Bottom

Near Spanish Bottom to Mineral Bottom

Mineral Bottom up to Ten Mile Canyon

Hite Marina to Imperial Canyon (base of Cataract Rapids)

Potash to Spanish Bottom

Date

June 17

June 19

June 24

June 30

Julyl

July 2

JulyS

July 9

July 13

July 14

July 15

July 21

July 23

July 25

July 26

July 28

July 30

Augusts

August 7

August 11

August 12

August 13

begin river km

54.0

54.0

81.9

81.9

77.1

270.6

77.1

81.9

77.1

29.9

336.5

77.1

118.0

118.0

192.7

192.7

77.1

81.9

-3.2

81.9

270.6

77.1

end km

48.2

81.9

0.0

-6.4

-6.4

321.4

-6.4

-6.4

29.9

336.5

301.9

118.0

130.1

160.6

218.4

112.4

-6.4

-6.4

81.9

129.3

322.8

 6.4

tot km

11.6

27.9

163.8

176.7

167.0

 58.8

167.0

176.7

47.2

41.9

34.5

81.9

24.1

85.1

51.4

 138.1

167.0

176.7

170.2

94.8

104.4

167.0

hours

1.5

2.5

9.6

9.3

9.03

5.5

9.33

8.8

4.5

7.5

5.5

4.5

2

8.1

3.5

9

9.95

5.55

5.28

5.55

6.37

9.1

Total number of surveying trips

River km surveyed

Hours spent surveying

Total fish contacts

Fish per hour of telemetry

Fish per river km surveyed

22

2136.9

141.96

69

0.486

0.032 or 1 fish per 33 river km surveyed

Telemetry effort shortened due to adverse weather

27
Table 2. A summary offish movements within Millard Bottom backwater during the 

acclimation period 6/16&17 - 6/19. Fish 1-7 placed into backwater 6/16 1615-2003, and 

fish 8-15 placed into backwater 6/17 @0900-1047.

Fish ID

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

6/171555

2

4

2

2

3

3

1

1

3

4

1

3

4

1

3

6/171605

3

4

2

3

3

3

1

2

1

4

3

2

2

3

3

6/17 1615

3

4

2

3

3

4

1

2

2

4

1

2

4

3

3

6/18 1030-1050

4

2

escaped

4

2

escaped

2

4

4

1

2

4

4

4

4

6/18 1241

4

1or2

4

?

1or2

2

3

3

?

4

3

3

3

6/18 2030-2130

4

2

4

4

4

1

4

3

1

2

?

3

4

28
Table 3. The following tables show razorback sucker utilization of 4 habitat categories 

during three time periods.

Days 0-14

near shore

3E

6E

10E

14E

15E

2C

2C

4C

5C

6C

7C

7C

7C

11C

14C

15C

eddy pool

3E

5E

8E

8E

14E

3C

5C

7C

11C

backwater

10E

15E

1C

1C

2C

4C

6C

6C

6C

channel

1E

3E

5E

10E

15E

2C

5C

7C

9C

Days 15-29

near shore

5E

6E

8E

6C

7C

8C

11C

11C

13C

15C

eddy pool

8E

14E

2C

4C

5C

14C

backwater

15E

channel

5E

Days 30-58

near shore

6E

6E

8E

2C

11C

11C

15C

eddy pool

6E 7C

backwater channel

1E

14E

14E

15E

15E

7C

7C

7C

7C

15C

29
Table 4. The following tables show razorback sucker utilization of 3 current categories 

during three time periods.

Days 0-14

slow (<1.4 kmTfirJ

3E

3E

6E

8E

8E

10E

14E

15E

15E

1C

1C

2C

5C

5C

6C

6C

6C

7C

7C

7C

11C

14C

15C

moderate (1.4 - 4.8 km/hr)

1E

5E

2C

2C

3C

4C

7C

11C

swift (>4.8 km/hr)

3E

5E

10E

14E

15E

2C

5C

6C

7C

9C

Days 15-29

slow (<1.4 km/hr)

5E

6E

8E

8E

14E

15E

6C

7C

8C

11C

13C

14C

moderate (1.4 - 4.8 km/hr)

11C

15C

swift (>4.8 km/hr)

5E

Days 30-58

slow (<1 .4 kmTTirJ

1E

6E

6E

6E

2C

7C

15C

15C

moderate (1.4 - 4.8 km/hr)

8E 11C

11C

swift (>4.8 km/hr)

14E

14E

15E

15E

7C

7C

7C

7C

30
Table 5. The following tables show razorback sucker utilization of 3 water depths 

categories during three time periods.

Days 0-14

0 -1.2 meters

3E

3E

6E

10E

14E

15E

1C

1C

2C

2C

2C

4C

5C

6C

6C

6C

7C

1.2 -3 meters

15E 5C

6C

7C

7C

7C

11C

14C

15C

>3 meters

1E

3E

5E

5E

8E

8E

10E

14E

15E

2C

3C

5C

6C

7C

9C

11C

Days 15-29

0 -1.2 meters

5E

8E

15E

6C

1.2 -3 meters

6E 7C

8C

11C

11C

13C

14C

15C

>3 meters

5E

8E

14E

2C

4C

5C

Days 15-29

0 - 1 .2 meters

6E

1.2 -3 meters

6E

8E

15E

11C

11C

15C

>3 meters

1E

6E

14E

14E

15E

2C

7C

7C

7C

7C

7C

15C

31
Table 6. The condition factors offish observed to use one of four habitat types are 

shown below as a function of both treatment and time period. Average condition factors 

are shown at the bottom of the columns.

Days 0-14

near shore

exp.

0.827

0.913

0.908

0.912

0.93

0.898

control

0.8

0.8

0.831

0.896

0.864

0.906

0.906

0.906

0.966

0.932

0.904

0.883

eddy pool

exp.

0.768

0.799

0.891

0.891

0.912

0.852

control

0.882

0.896

0.906

0.966

0.913

backwater

exp.

0.93

0.930

control

0.734

0.734

0.8

0.864

0.864

0.864

0.810

channel

exp.

0.743

0.768

0.799

0.908

0.93

0.830

control

0.8

0.896

0.906

1.057

0.915

Days 15-29

near shore

exp.

0.799

0.913

0.891

0.868

control

0.864

0.906

0.921

0.966

0.966

0.879

0.904

0.915

eddy pool

exp.

0.891

0.912

0.902

control

0.8

0.831

0.896

0.932

0.865

backwater

exp.

0.93

0.930

control

channel

exp.

0.799

0.799

control

Days 30-58

near shore

exp.

0.913

0.913

0.891

0.906

control

0.8

0.966

0.966

0.904

0.909

eddy pool

exp.

0.913

0.913

control

0.906

0.906

backwater

exp. control

channel

exp.

0.743

0.912

0.912

0.93

0.93

0.885

control

0.906

0.906

0.906

0.906

0.904

0.906

32
Table 7. The condition factors of fish observed to use habitats subjected to three 

different current intensities are shown below as a function of both treatment and time 

period. Average condition factors are shown at the bottom of the columns.

Days 0-14

slow(<1.4km/hr)

exp.

0.768

0.768

0.913

0.891

0.891

0.908

0.912

0.93

0.93

0.879

control

0.734

0.734

0.8

0.896

0.896

0.864

0.864

0.864

0.906

0.906

0.906

0.966

0.932

0.904

0.869

moderate (1.4-4.8 km/hr)

exp.

0.743

0.799

0.771

control

0.8

0.8

0.882

0.831

0.906

0.966

0.864

swift (>4.8 km/hr)

exp.

0.768

0.799

0.908

0.912

0.93

0.863

control

0.8

0.896

0.864

0.906

1.057

0.905 \

Days 15-29

slow (<1. 4 km/hr)

exp.

0.799

0.913

0.891

0.891

0.912

0.93

0.889

control

0.864

0.906

0.921

0.966

0.879

0.932

0.911

moderate (1.4-4.8 km/hr)

exp. control

0.966

0.904

0.935

swift (>4.8 km/hr)

exp.

0.799

0.799

control

Days 30-58

slow (<1. 4 km/hr)

exp.

0.743

0.913

0.913

0.913

0.871

control

0.8

0.906

0.904

0.904

0.879

moderate (1.4-4.8 km/hr)

exp.

0.891

0.891

control

0.966

0.966

0.966

swift (>4.8 km/hr)

exp.

0.912

0.912

0.93

0.93

0.921

control

0.906

0.906

0.906

0.906

0.906

33
Table 8. The following tables summarize the condition factors of razorback suckers that 

utilized habitats ranging from <1.2, 1.2-3.0, and >3m deep during three time periods. 

Average condition factors are shown at the bottom of the columns. Razorback suckers 

inhabiting water 1.2-3.0 meters deep have higher condition factors than fish in either 

shallower or deeper water, irregardless of treatment or time since release.

Days 0-14

0-1.2 meters

exp.

0.768

0.768

0.913

0.908

0.912

0.93

0.867

control

0.734

0.734

0.8

0.8

0.8

0.831

0.896

0.864

0.864

0.864

0.906

0.827

1.2-3 meters

exp.

0.93

0.930

control

0.896

0.864

0.906

0.906

0.906

0.966

0.932

0.904

0.910

>3 meters

exp.

0.743

0.768

0.799

0.799

0.891

0.891

0.908

0.912

0.93

0.849

control

0.8

0.882

0.896

0.864

0.906

1.057

0.966

0.910

Days 15-29

0 - 1.2 meters

exp.

0.799

0.891

0.93

0.873

control

0.864

0.864

1.2 -3 meters

exp.

0.913

0.913

control

0.906

0.921

0.966

0.966

0.879

0.932

0.904

0.925

>3 meters

exp.

0.799

0.891

0.912

0.867

control

0.8

0.831

0.896

0.842

Days 30-58

0 - 1.2 meters

exp.

0.913

0.913

control

1.2-3 meters

exp.

0.913

0.891

0.93

0.911

control

0.966

0.966

0.904

0.945

>3 meters

exp.

0.743

0.913

0.912

0.912

0.93

0.882

control

0.8

0.906

0.906

0.906

0.906

0.906

0.904

0.891

34
FIGURES

Figure 1. A map of the study site. Multiple surveys were conducted on the boxed-in 

portions of both the Colorado and Green Rivers. The portions of both rivers below the 

transect lines and above the boxed areas, as well as Cataract Canyon rapids, were only 

surveyed once.

Upper Exteat of 

Tracking km 218.4

Upper Extent of 

Tracking km 155

Potash Boat Ramp

Begfa Cataract Canyoa Rapids (21 lun)

Ead Rapids, Bcgia I J*e Powdl

35
Figure 2A. The following 9 graphs show the dispersal distances (km) for razorback 

suckers in the experimental treatment. Fish 15E was the only sucker to still remain in the 

Green River by the end of the project.

1E

20 40 

Days since re least

S

1 D

!

c

1

if

e

1

8E

125 -I 

100

75 

50

25

0< -r- ,-

S~-

0 20 40 60

Days since release

2E

20 40 

Days since release

Total distance point frm release 

(km)

10E

125, 

100 

75 

50 

25

C

S

) 20 40 60

Days since release

Total distance from release (km) point 

3E

125 1 

100 

75 

50 

25 

0< 

(

,**

> 20 40 60

Days since release

It

5 p

*- 1

14E

125 , 

100

7fi

50 

25X" '

0 20 40 60

Days since release

I 1

ill

f

"£

"ip

5E

125, 

100

75 

50

25

0.. r ,_--

0 20 40 60

Days since release

distance Total release from point (km)

15E

125 , 

100 

75 

50 

25 

0. 

C

^* - »

) 20 40 60

Days since release

 I

g i

5 g |-

 *~

"I

6E

125,

100

75

50 

25

X " ' '

0 20 40 60

Days since release

36
Figure 2B. The following 14 graphs show the dispersal distances (km) for razorback 

suckers in the control treatment. Four graphs could not fit on this page and are shown in 

the next Figure (3C).

6 ^

Total distance 1release point (1 W838 o 

1C

X

} 20 40 60

Days since release

2C

20 40 

Days since release

60

3C

20 40 

Days since release

4C

1 | 125 n

8¥ ioo

Is 75

1 J 50

'| 25

£ 9 8 oi n .

0 

^

20 40 60

Days since release

SC

20 40 

Days since release

|

S

I o

5

I

r

i

I

i

6C

125 -i

100

75 

50

25

.s*

0 < > ^^ , , -

0 20 40 60

Days since release

|

S

 o

B

I

r

I

i

i

. 7C

125-j

100

75 

50

25

^ _ __

U v 

/

i i i

0 20 40 60

Days since release

from nee 

«

 oI

I

¥ 5&

i

8C

125 -, 

100 

75

50 

25 

0- 

(

/

) 20 40 60

Days since release

|

S

i

 o

I

r

I

I

1

9C

125-,

100

75 

50

25

0« , , ,

^*

0 20 40 60

Days since release

11C

E -»

|| 125 -,

 r 100

f

a re 

_ J 50

I 1 25

|l ° ]

/^A ^

H 0 20 40 60

Days since release

37
Total distance from 

release point (km)

Ui 

00

Total distance from 

release point (km)

ro crt --J o ro 

o en o en o 01

Total distance from 

release point (km)

w 

O

Total 

relea
Figure 3 A. The graphs show both the estimated average rates of daily movements 

(km/day) as well as the direction of the movements (+/-km/day) for experimental 

treatment fish. Solid lines show the trend in average daily movement rates, while dashed 

lines show the trend in the direction of travel.

1E

15.000

7.500

0.000

II 

-7.500

6E

10 20 30 40 " flJ * 60

Days since release

Days since release

5E

15.000-,

7.500

X. I

-7.500

-15.000

m

f^^~*

-. 

i 10 20 30 40 50 60

" "

Days since release

8E

15.000 -,

7.500

 o

£ I

-7.500

-15.000

 , j

I 10* 20 30 40 50 60

Days since release

10E

15.000-,

>, 750°

TJ

X. I

-7.500

-15.000

4»* **

I % 20 30 40 SO 60

Days since release

14E

Days since release

15E

15.000 n

7.500

|

1 0.000

2 <

-7.500

-15.000

. * _____________ f. ^r~~~~~^^^f^^^^^^^^^^^^f^i^ ____ . 

i m 20 30 40 50 60

Days since release

39
Figure 3B. The graphs show both the estimated average rates of daily movements 

(km/day) as well as the direction of the movements (+/-km/day) for control treatment 

fish. Solid lines show the trend in average daily movement rates, while dashed lines 

show the trend in the direction of travel.

1C

15.000 n

7.500

X

 D

X I

-7.500

-15.000

> *

§ 10 20 30 40 50 60

Days since release

2C

30.000

15.000

X

^ 0.000 

tp I

-15.000

-30.000

 *

- -*- I f. ft

1 « 20 30 40 ^0" 60

Days since release

3C

15.000 -I

7.500

T>

 g 0.000

^

-7.500

-15.000

4^^Bi>^^

**

) 10^ " 20 30 40 50 60

"

Days since release

4C

15.000 n

7.500

 D

x 1

-7.500

-15.000

^ *~""^~ ~*~~^

! «-»" "bo 40 50 60

Days since release

5C

Days since release

6C

15.000 n

7.500-

X

1 0.000

2 i

-7.500

-15.000

_ .mia - » "^ mo 40 so eo

Days since release

7C

15.000-,

7.500

X

 D 

J 0.000 

I

-7.500

-15.000

__ 1 ^* a^ 

 ^ s in^^K^ai ^f^^^'^^^^^^^^f' 

> "10" "20 30 40 50 60

Days since release

11C

15.000 n

7.500

X

T>

X 1

-7.500

-15.000

«

^X^

) 10 a *20 30 40 50 60

Days since release

14C

15.000-, 

4

7.500

X

 D

-7.500

-15.000

^^>

10 20 30 40 50 60

-

1

Days since release

15C

15.000

7.500

X

S 

^ 0.000 

X I

-7.500

-15.000

*

I Jfl0" 2ir 1"3o""40~50^60

Days since release

40
Condition Factor

CO

en 

o

pop 

^ bo CD

o 

o

CD

% 

S

en 

o

en 

o 

o

CD

01

m 

6

Condition Fact

pop 

^ bo CD

en 

o

o> 

en 

o

I

CO

IT

00

en 

o

O

en 

o
Figure 5. The following two graphs depict daily flow rates of the Colorado and Green 

Rivers within Canyonlands National Park and vicinity during the study period.

30000

25000

20000

P 15000 

(0

w 10000

5000

Green River Daily Discharge 1998

Razorbacks 

released

11/16/97 1/5/98 2/24/98 4/15/98 6/4/98 7/24/98 9/12/98 11/1/98

30000 n

25000

?g 20000

CD

g> 15000

CO

g 10000

5000

Colorado River Daily Discharge 1998

Razorbacks 

released

1st razorback appears 

in Colorado River

Reject is over

11/16/97 1/5/98 2/24/98 4/15/98 6/4/98 7/24/98 9/12/98 11/1/98

42
Figure 6. Graph A compares the average dispersal away from the stocking site between 

experimental fish (solid red lines) and control fish (dashed black lines). Graph B shows 

that the average rate of razorback sucker movement (km/day) decreases from an initially 

high rate following stocking. Graph C illustrates the average direction that razorback 

suckers traveled; there is a significant treatment affect (p = 0.042). The error bars used 

for the graphs are one standard error of the mean.

A 100 -]

| ~ 80

 §

g- tS 60

Q 8

o c 40

§Q 20

0 -

<

i

*~~^^**^'

\

m '

L ^**^*'s(

i

>

0-14 15-29 30-58

Time Period (days)

B

_ js 5^

0 =

o> o ^^ 4

5 o> <u

0)5 E A ^ W

O ^* 

< Q

3 

£ 2

0-14 15-29 30-58

Time Period (days)

0-14 15-29 30-58

Time Period (days)

43
APPENDICES

Appendix 1. Summarizes the rate (km/day) of razorback movements. Rates were 

calculated by dividing the distance traveled by the number of days between contacts. 

Only fish that were contacted at least twice during one of the three time periods are 

shown. The time periods are: 0 = 0-14,15 = 15-29, 30 = 30-58 days.

tag ID

11C

11C

11C

12C

13C

14C

14C

15C

15C

15C

15C

1C

1C

2C

2C

2C

2C

2C

2C

3C

4C

5C

5C

5C

5C

6C

6C

6C

6C

6C

7C

7C

7C

7C

7C

7C

7C

Days since release

14.06

21.10

22.14

28.08

15.08

0.33

15.09

7.09

22.21

55.96

56.01

0.95

7.79

0.96

7.79

14.68

27.87

28.92

56.62

7.82

0.93

7.78

13.67

14.70

27.83

0.91

7.73

13.65

22.74

28.63

7.79

14.70

27.71

43.75

49.98

51.00

57.74

trtrnnt

con

con

con

con

con

con

con

con

con

con

con

con

con

con

con

con

con

con

con

con

con

con

con

con

con

con

con

con

con

con

con

con

con

con

con

con

con

time

15

30

30

30

30

15

30

15

30

58

58

15

15

15

15

15

30

30

58

15

15

15

15

15

30

15

15

15

30

30

15

15

30

58

58

58

58

distance

55.52

54.09

54.14

69.20

86.09

4.18

80.30

25.91

29.13

91.89

91.89

4.18

42.00

4.18

38.78

74.83

58.82

79.34

93.50

54.07

4.18

48.04

53.91

57.29

61.47

5.95

30.90

30.90

47.23

66.62

42.64

64.85

54.07

56.32

56.48

56.40

56.40

average km/day

3.95

0.21

0.05

2.46

5.67

12.89

5.16

3.66

0.21

1.86

0.00

4.42

5.53

5.54

5.06

5.24

1.93

19.68

0.51

6.91

4.54

6.18

1.00

3.29

0.32

6.48

3.66

0.00

1.80

3.32

5.47

0.09

0.83

0.14

0.03

0.08

0.00

directed km/day

-3.74

-0.21

-0.05

-2.46

-5.67

-12.89

-5.16

-3.66

-0.21

-1.86

0.00

-4.42

-5.53

-5.54

-5.06

0.80

-1.93

-19.68

-0.51

-6.91

-4.54

-6.18

-1.00

-3.29

-0.32

-6.48

-3.66

0.00

-1.80

-3.32

-5.47

-0.09

-0.83

-0.14

-0.03

0.08

0.00

44
Appendix 1. Continued.

9C

10E

10E

14E

14E

14E

14E

14E

14E

15E

15E

15E

15E

15E

1E

1E

1E

3E

5E

5E

5E

5E

6E

6E

6E

6E

6E

6E

8E

8E

8E

8E

8E

7.13

5.16

11.13

12.16

19.17

25.25

47.40

48.12

48.42

5.13

11.08

20.30

47.16

49.11

12.35

54.06

54.09

6.30

5.24

12.36

19.41

24.23

13.05

20.08

26.04

41.56

42.09

48.33

11.16

12.16

19.19

19.23

25.12

con

exp

exp

exp

exp

exp

exp

exp

exp

exp

exp

exp

exp

exp

exp

exp

exp

exp

exp

exp

exp

exp

exp

exp

exp

exp

exp

exp

exp

exp

exp

exp

exp

15

15

15

15

30

30

58

58

58

15

15

30

58

58

15

58

58

15

15

15

30

30

15

30

30

58

58

58

15

15

30

30

30

16.50

17.38

46.35

54.07

54.88

56.32

56.48

56.48

12.38

6.12

24.94

22.45

12.38

12.38

106.37

85.77

85.77

12.23

54.07

109.99

126.16

92.69

58.66

58.50

58.42

59.62

57.13

59.62

59.62

59.62

59.62

59.62

94.95

2.32

3.37

4.86

4.45

0.12

0.24

0.01

0.00

0.00

1.12

3.16

0.27

8.82

0.00

8.62

2.10

0.00

2.14

6.91

12.32

2.30

6.94

4.70

0.02

0.01

0.00

0.46

0.40

5.18

0.00

0.00

0.00

1.39

-2.32

-3.37

-4.86

-4.45

-0.12

-0.24

-0.01

0.00

0.00

-1.12

-3.16

0.27

0.37

0.00

-0.14

-2.10

0.00

-2.14

-6.91

12.32

2.30

-6.94

-3.97

-0.02

-0.01

0.00

-0.46

-0.40

-5.18

0.00

0.00

0.00

1.39

45
Appendix 2. Summarizes the furthest distance each contacted fish had traveled during 

the three time periods. The time periods are: 0 = 0-14, 15 = 15-29, 30 = 30-58 days.

Tag ID

11C

11C

12C

13C

14C

15C

15C

15C

1C

2C

2C

2C

3C

3C

4C

4C

5C

5C

6C

6C

7C

7C

7C

8C

9C

10E

14E

14E

14E

15E

15E

15E

1E

1E

3E

5E

5E

6E

6E

6E

8E

8E

days since release

14.06

21.10

28.08

15.08

15.09

7.09

22.21

55.96

7.79

14.68

28.92

56.62

7.82

26.74

0.93

27.85

14.70

27.83

7.73

28.63

14.70

27.71

49.98

15.63

7.13

11.13

12.16

25.25

47.40

11.08

20.30

47.16

12.35

54.06

6.30

12.36

19.41

13.05

26.04

48.33

11.16

19.19

treatment

con

con

con

con

con

con

con

con

con

con

con

con

con

con

con

con

con

con

con

con

con

con

con

con

con

exp

exp

exp

exp

exp

exp

exp

exp

exp

exp

exp

exp

exp

exp

exp

exp

exp

time

15

30

30

30

30

15

30

58

15

15

30

58

15

30

15

30

15

30

15

30

15

30

58

30

15

15

15

30

58

15

30

58

15

58

15

15

30

15

30

58

15

30

distance

55.52

54.14

69.2

86.09

80.3

25.91

29.13

91.89

42.00

74.83

79.34

93.5

54.07

121.74

4.18

61.47

57.29

61.47

30.90

66.62

64.85

54.07

56.48

88.51

16.50

46.35

54.07

56.32

56.48

24.94

22.45

12.37

106.37

85.77

12.23

109.99

126.16

58.66

58.42

59.62

59.62

94.95

46
Appendix 3. Summary offish lengths, weights, condition factors, and telemetry 

contacts. An * denotes fish that reached Lake Powell. An # indicates that fish were 

contacted in Cataract Canyon Rapids.

Fish ID

1E

2E

3E

4E

5E

6E

7E

8E

9E

10E

11E

12E

13E

14E

15E

1C

2C

3C

4C

5C

6C

7C

8C

9C

10C

11C

12C

13C

14C

15C

# days acclimation

2.540

2.549

'.913-1.750

2.552

2.545

'.913-1.750

2.536

1.953

1.924

1.917

1.960

1.951

1.930

1.914

1.972

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

Length (mm)

464

470

451

425

438

419

394

476

445

465

419

406

445

425

438

400

470

445

464

457

419

483

457

445

416

415

457

413

375

432

Weightfg)

740

858

704

712

672

672

520

962

796

912

588

520

714

702

782

470

830

775

828

856

636

1018

880

928

582

692

848

618

490

728

Conditin factor

0.743

0.827

0.768

0.925

0.799

0.913

0.852

0.891

0.906

0.908

0.799

0.775

0.813

0.912

0.93

0.734

0.8

0.882

0.831

0.896

0.864

0.906

0.921

1.057

0.809

0.966

0.887

0.879

0.932

0.904

Contacted?

Y

Y

Y

-

Y

Y

-

Y

-

Y

-

-

-

Y

Y

Y

Y

Y

Y

Y

Y

Y

Y

Y

-

Y

Y

Y

Y

Y

# of Contacts

2

1

1

-

5

5

-

4

-

2

-

-

-

5

5

2

6

2

2

4

5

7

1

1

-

3

1

1

2

3

47