Draft Plan for Non-native Fish Control in the 

Colorado River Ecosystem 

2002-2006 

Submitted to: 

 Glen Canyon Dam Adaptive Management Program 

 Technical Work Group 

December 2002 

Prepared by: 

Non-native Control Ad hoc Committee Members 

Bill Persons, Arizona Game and Fish Department, Chair 

Bill Davis, EcoPlan Associates 

Gary Burton, Western Area Power Administration 

Dennis Kubly, Bureau of Reclamation 
Non-native Control Ad hoc Group Report 12/20/2002 

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TABLE OF CONTENTS 

EXECUTIVE SUMMARY ............................................................................................................ 2 

INTRODUCTION/ BACKGROUND............................................................................................ 3 

ASSUMPTIONS............................................................................................................................. 5 

PROBLEMS FACED BY NATIVE FISHES ................................................................................ 6 

Cold water temperature............................................................................................................... 6 

Trout Predation ........................................................................................................................... 7 

Channel Catfish, Bullhead, and Common Carp Predation ......................................................... 7 

Predation and Competition with Other Non-native Fishes......................................................... 8 

STRATEGIES TO ADDRESS THE PROBLEMS ........................................................................ 9 

Brown trout and rainbow trout predation.................................................................................... 9 

Channel catfish, black bullhead and carp predation ................................................................. 10 

Competition with non-native fishes.......................................................................................... 10 

MONITORING AND RESEARCH ............................................................................................. 11 

MANAGEMENT CONSIDERATIONS...................................................................................... 12 

Timing concerns........................................................................................................................ 12 

Social concerns ......................................................................................................................... 12 

Biological concerns................................................................................................................... 13 

Institutional concerns................................................................................................................ 13 

RECOMMENDATIONS.............................................................................................................. 13

Draft Work Plans for Research and Monitoring 2002-2006......................................................... 15 

Project 1: Feasibility Study to determine the efficacy of using a weir in Bright Angel Creek 

to capture brown trout............................................................................................................... 15 

Project 2: Mechanical removal of non-native fishes (primarily salmonids) from the Colorado 

River near the confluence with the Little Colorado River........................................................ 16 

Project 3: Fluctuating Flows to Disadvantage non-native fishes. ......................................... 16 

Project 4: Evaluation of catfish and carp removal methods in Little Colorado River. ......... 17 

REFERENCES ............................................................................................................................. 18 

APPENDICES .............................................................................................................................. 21 

Technical Work Group ad hoc members: ................................................................................. 23 

Summary of committee work done........................................................................................... 24 

Copy of cover letter sent with non-native fish control matrix survey. ..................................... 25 

Copy of control matrix distributed to select individuals........................................................... 26 

Names of survey participants.................................................................................................... 27 

FIGURES...................................................................................................................................... 33 

Figure 1. Estimated humpback chub recruitment and rainbow trout catch per 10 hours of 

electrofishing near the mouth of the LCR............................................................................. 33 

Figure 2. Estimated humpback chub recruitment and brown trout catch per 10 hours of 

electrofishing near the mouth of the LCR............................................................................. 34 
Non-native Control Ad hoc Group Report 12/20/2002 

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EXECUTIVE SUMMARY 

Non-native fish have been in the Colorado River system since the late 1800’s. These non-native 

fishes compete with and prey upon endangered humpback chub (Gila cypha) in the vicinity of 

the Little Colorado River. Since implementation of the Record of Decision, salmonids have 

increased in number and appear to be specifically problematic. Other factors contribute to the 

endangered status of the humpback chub, but reducing the non-native pressure on humpback 

chub through mechanical control and flow modification appears to be the next best logical step 

to improve humpback chub recruitment and survival. 

The Adaptive Management Work Group directed a Technical Work Group ad hoc committee to 

develop a research, monitoring, and management work plan for the period 2002-2006 that will 

address the need to reduce non-native fish predation/competition as stated in Management 

Objective 2.6. The committee assumes the non-native control plan’s recommendations may not 

solve survival and recruitment problems of humpback chub and other native fish in the Grand 

Canyon, but in concert with other management activities will reduce some problems faced by 

these fish. The committee also assumes that maintenance of the Lees Ferry recreational trout 

fishery remains a goal for the Adaptive Management Program, and it is not the intent of nonnative control to adversely impact that fishery. 

Cold, clear water enhances conditions for salmonid non-natives and inhibits native fish 

recruitment and survival. Cold water temperature also suppresses spawning, growth, and 

distribution of warmwater non-native fish and associated pathogens and parasites. In addition to 

cold clear water, problems faced by native fish in the Colorado River Ecosystem include 

predation and competition at all life stages by trout, catfish and carp. Other species also become 

problematic for native fish under certain conditions. 

Strategies to combat these problems include physical removal of predator/competitor fish; 

suppression of predator/competitor species spawning; and temperature, flow and turbidity 

management to disadvantage non-native species. Monitoring will be necessary to determine 

relative success of these actions. The ad hoc committee has provided recommendations to 

support these strategies and draft work plans for implementation during 2002-2006. Major 

recommendations include increasing public awareness concerning non-native fish impacts on 

native fishes, control of predatory trout in Bright Angel Creek, mechanical removal of trout near 

the confluence of the Little Colorado River by electrofishing, use of managed flows (increased 

daily fluctuations) to reduce non-native fish recruitment, and a temperature control device on 

Glen Canyon Dam. Any feasible methods to control non-native species should be implemented 

immediately because of the urgent need to protect humpback chub. We recommend appropriate 
Non-native Control Ad hoc Group Report 12/20/2002 

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agencies be encouraged and supported in efforts to fund and implement efforts to control nonnative fishes. 

INTRODUCTION/ BACKGROUND 

Native fish in the Colorado River, and specifically endangered humpback chub (Gila cypha) 

below Glen Canyon Dam, historically encountered extreme conditions of temperature, flow and 

turbidity. Few historic predators, long life span, high fecundity and hardy physiology allowed 

these fish to survive despite harsh environmental conditions.

Since the 1800’s, approximately 67 fish species have been introduced to the Colorado River and 

fifty-seven have become established (USBR 1998). Twenty-four non-native fishes have been 

reported from Grand Canyon since 1958 and 13 are present today (Valdez et al. in press). Carp 

and catfish were two of the earliest non-native fish introduced by the U.S. Fish and Wildlife 

Service. Within 100 years of their introduction, these two species dominated the fish 

community, constituting about 90 percent of the fish captured (USBR 1995). The National Park 

Service introduced rainbow trout into Bright Angel Creek beginning in 1923 and continuing until 

1964. Brown trout were also introduced into Bright Angel Creek in 1930 and 1934. After 

closure of Glen Canyon Dam, rainbow trout were introduced, establishing the prized Lees Ferry 

tailwater fishery. In response to suitable temperature, flow, and water quality, these salmonid 

species have expanded their presence into areas previously occupied by humpback chub (HBC) 

(Figures 1 and 2) (Coggins and Walters 2001). Rainbow and brown trout populations below 

Lees Ferry are now estimated to approach one (1) million fish although these estimates may be 

biased high (Speas 2001). 

The few estimates which are available for native fish remaining in Glen and Grand canyons 

suggest they are at least two orders of magnitude less than the non-native fish population, i.e. 

less than one percent of the composite fish population (Speas et al. 2002, Coggins and Walters 

2001). Native fishes, especially the endangered humpback chub have been in decline since 

before of the Record of Decision (ROD) was issued for Glen Canyon Dam operations in 1996. 

Recent studies indicate the decline has continued and possibly become more severe since 

implementation of interim and ROD flows (Coggins and Walters 2001, GCMRC unpublished 

data, Figures 1, 2). Although reasons for the decline in recruitment of HBC are not certain, cold 

water temperature, reduced turbidity, exotic parasites, modified flow regimes, and increased 

numbers of non-native predators and competitors are implicated. 

In the Proceedings of a Symposium and Workshop on Restoring Native Fish to the Lower 

Colorado River, July 1999, Valdez et al. stated: 
Non-native Control Ad hoc Group Report 12/20/2002 

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Non-native fish occur sympatric with native species throughout the Colorado 

River in Grand Canyon as well as in tributaries (AGFD 1996, Valdez and Ryel 

1997). Use of similar habitats and foods implies competition for many species 

and predation by channel catfish, black bullhead, brown trout, and rainbow trout 

has been documented on all four native fish species. In the LCR, Marsh and 

Douglas (1997) reported that approximately 4% of channel catfish collected 

contained 1-7 humpback chub and approximately 1.7% of rainbow trout and 16% 

of black bullhead examined contained humpback chub. In the mainstem Colorado 

River, Valdez and Ryel (1997) reported that 10.4% of brown trout and 1.5% of 

channel catfish contained an average of 2 and 1 humpback chub, respectively. 

The current HBC population is reaching a level where attempts to increase recruitment may be 

critical to the continued existence of the species in the Colorado River Ecosystem (CRE). 

Control of predatory and competitive non-native fish is probably the first, best option to enhance 

recruitment and survival of native fish, specifically HBC, in the CRE. In response to the 

potentially critical condition of the Grand Canyon HBC population the AMWG gave direction 

for developing a five-year work plan for controlling impacts of non-natives on native fish 

recruitment and survival in the Grand Canyon. That direction was delivered in the form of the 

following motion, passed, as amended, January 18, 2002. 

“In support of Goal 2, the AMWG recommends the following actions subject to environmental 

compliance to include assessing recreational use, ESA, and consultation with tribes and other 

affected state agencies: 

1. Evaluate methods to remove non-native fish except for rainbow trout from Bright Angel 

Creek in 2002; 

2. Evaluate methods to remove non-native fish from the LCR in 2002; 

3. Gather public input, and conduct public education and environmental compliance on 

long-term removals in #1 and #2 above; 

4. Establish a TWG ad hoc committee to develop a 2002-2006 research, monitoring and 

management work plan for meeting MO 2.5 and 2.6 of the 17 August 2001 draft of the 

AMP Strategic Plan. The TWG will report back to the AMWG at the next meeting. 

5. Using data from #1 - #4 above, make recommendations on future removals.” 

The Management Objectives (MO) 2.5 and 2.6 (as referenced in the motion) are: 

MO 2.5. Attain humpback chub condition in the LCR and mainstem aggregations. 

Target is viable populations and removal of jeopardy. 
Non-native Control Ad hoc Group Report 12/20/2002 

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MO 2.6. Reduce native fish mortality due to non-native fish predation/competition as 

a percentage of overall mortality in the LCR and mainstem to increase native fish 

recruitment. 

(Note: numbering of MO’s is that used in the August 17, 2001 Draft AMP Strategic Plan). 

The TWG ad hoc committee created by Item 4 in the motion is identified in the Appendix. In 

creating this document as directed, the committee reviewed the AMWG’s specific intent in 

creating the motion. In reviewing the AMWG minutes from the January 18, 2002 meeting, the 

committee believed the focus of the AMWG discussion was non-native fish removal (i.e. 

control) in Grand Canyon. We recognize that there are other issues affecting native fishes that 

require attention, but did not feel the AMWG intended this group take on the larger, attendant 

charge of MO 2.5. We see this charge requiring a larger more comprehensive plan for aiding

native fishes. This non-native control plan would become an integral part of that larger plan 

when created. Both plans need to be fully reviewed by and integrated with GCMRC’s long-term 

monitoring and research plan. To assist in that effort we have provided the Information Needs 

associated with MO 2.6 and a brief synopsis of the status of those Information Needs in the 

Appendix to this report. 

ASSUMPTIONS 

 

The Committee’s assumptions regarding non-native fish control efforts are as follows: 

• Predation and competition by non-native fishes is a major threat to native fishes.

• Control of non-native fishes is not intended to adversely impact the Lees Ferry trout 

fishery (Goal 4 of the AMP).

• Although closely related, pursuing MO 2.5 is beyond the scope of the non-native control 

committee’s report with regard to researching, monitoring, and managing non-native fish 

control for the benefit of native fish in the CRE.

• Non-native control derived from MO 2.6 will necessarily include consideration of 

mainstem Colorado River, Little Colorado River, and other appropriate tributary and 

watershed issues. 

• Completion of the ad hoc charge may not result in complete control of the non-native 

problem or removal of jeopardy for humpback chub without other complimentary 

management actions. However, without some level of control of predation and 

competition from non-native fish, other measures to aid native fish may show limited 

success.
Non-native Control Ad hoc Group Report 12/20/2002 

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• Control of predation and competition from non-native fish using mechanical removal and 

increased daily flow fluctuations is the least risky and likely least costly of several 

options for enhancing recruitment of native fishes such as a Temperature Control Device 

and Low Steady Summer Flows. 

• Control strategies will not eliminate all non-native fishes, but if used in the right place at 

the right time may provide enough suppression to give an advantage to native fishes and 

thereby benefit their recruitment and survival.

• Captured non-native fishes will be dealt with in a method that is socially acceptable, 

legal, and cost-effective. 

• A method (or methods) can be found that will accomplish the desired control while 

meeting Park Service goals for use of “minimum tool.” 

• Actions that result in benefits to humpback chub may benefit other native fish species in 

a similar fashion. 

PROBLEMS FACED BY NATIVE FISHES 

Cold water temperature 

Cold water has been implicated in the decline of warm-water native fishes in the CRE, through 

direct mortality, impacts on ability of native fishes to spawn, and by reducing survival and 

swimming ability of early life stages. At the same time, cold water limits parasites such as Asian 

tapeworm (Bothriocephalus acheilognathi) and proliferation of many warm-water non-native 

fish such as striped bass, various catfish, carp, shiners, and various centrarchids (sunfish species 

like bass, bluegill). Prior to the onset of year-round cold water in the canyon, carp and catfish 

comprised the majority of the fish community and now are less common. Cold water releases 

from Glen Canyon Dam limit warmwater non-native fish reproduction and survival in the 

mainstem just as they do native fish. 

 

Rainbow and brown trout are the primary predators/competitors in most of the mainstem 

Colorado River. Their ranges overlap with native fish adults in the mainstem Colorado River but 

they are largely absent from warmwater fish spawning and nursery areas. While cold water 

restricts native fish spawning to warmer tributaries, it also isolates young warmwater native fish 

from the cold-water predators thus providing some relief from predation. Native fish are in a 

dilemma wherein they are both harmed and helped by cold water conditions due to the effects on 

their predators and competitors. 
Non-native Control Ad hoc Group Report 12/20/2002 

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Trout Predation

Large-bodied BNT and RBT reduce recruitment of native fish through direct predation in the 

mainstem Colorado River (COR) and in the Little Colorado River (LCR). Mature BNT are 

piscivorous and rainbow trout are known opportunistic piscivores. Predation on HBC and other 

native fishes in Grand Canyon by brown trout and rainbow trout has been documented by several 

researchers (Minckley 1978, Carothers et al. 1981, Valdez and Ryel 1995, Marsh and Douglas 

1997). Limited attention has been given to predicting population level effects on native fish, but 

Valdez and Carothers (1998) provided estimates of annual HBC predation in Grand Canyon and 

Miller (1968) attributed elimination of speckled dace in Tapeats Creek to effects of rainbow 

trout. Speckled dace were common in Bright Angel Creek in the 1970s (Minckley 1978) and 

were reported as very rare in the 1990s after an increase in BNT abundance (Otis 1994). 

Data from a March 2001 monitoring trip produced population estimates of 369,000 RBT (95% 

CI: 216,000-474,000) between river mile (RM) 39-196, and 84,000 BNT (95% CI: 55,000-

114,000) between RM 39 and 160 (Speas et al. 2002). Although both species of salmonids are 

being monitored on an annual basis, predation rates in the mainstem are uncertain. Recent studies 

suggest predation on native fishes may be a problem. Valdez and Ryel (1997) reported that 

10.4% of brown trout in the mainstem contained an average of two humpback chub. Marsh and 

Douglas (1997) found during a four-year study in the LCR that humpback chub and other native 

fishes were significant components of the diet of introduced predatory fish species (including 

BNT and RBT) (13.7% frequency of occurrence in stomachs having food). 

Channel Catfish, Bullhead, and Common Carp Predation 

Channel catfish (CCF) were introduced into the Colorado River system in the 1890s (Tyus and 

Nikirk 1990). They are considered a major threat to the native fish fauna of the Colorado River 

basin by a majority of biologists surveyed (Hawkins and Nesler 1991, Tyus and Saunders 1996). 

Biologists surveyed for this report also ranked CCF high among perceived threats (see Survey 

Response section). They are known to prey on young Colorado pikeminnow, razorback sucker 

and Gila spp. (Coon 1965; Taba et al. 1965; Marsh and Brooks 1989) and there is evidence of 

attempted predation on humpback chub (Kaeding and Zimmerman 1983; Karp and Tyus 1990). 

Suspected impacts include predation on native fishes, especially larvae and juveniles, and 

competitive interactions (Lentsch et al. 1996). 

Large-bodied ictalurids including channel catfish (CCF) and black bullhead (BBH), as well as 

carp (CRP) reduce recruitment of native fish through direct predation. Some data have been 

collected on predation within the LCR (Marsh and Douglas 1997); however, densities of CCF, 

BBH and CRP in the LCR are largely unknown. Present monitoring activities sample young-of-
Non-native Control Ad hoc Group Report 12/20/2002 

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the-year fishes but are not effective in capturing most adults. During 2002, evaluations to 

develop more effective capture and monitoring methods for adult CCF, BBH and CRP were 

relatively disappointing in that few fish were captured. 

Evaluation of limited numbers of CCF stomachs in the LCR showed some predation on HBC, 

but most stomachs examined did not contain fish. Some adult HBC captured in the LCR have 

also been reported to have what appear to be CCF bite marks (Kaeding and Zimmerman 1983). 

Catfish as large as 16 pounds have been collected in the LCR, and fish of this size are capable of 

preying on large HBC. Black bullheads have also been demonstrated to prey on native fishes 

(Marsh and Douglas 1997), and bullheads are common in the LCR (GCMRC, unpublished data). 

Common carp were introduced in the Colorado River about 1880 and are now common or 

abundant throughout the basin. Common carp are ranked fourth on a list of 28 non-native fish 

species considered to adversely impact native fishes in the Colorado River and southwestern 

streams (Lentsch et al. 1996). Respondents to the survey collected for this plan ranked CRP 

high on the list of species perceived as threats to native fishes. 

Predation and Competition with Other Non-native Fishes

Other non-native fish are common in the CRE and may reduce recruitment of native fish through 

competition and predation. Small-bodied non-natives are capable of multiple spawns per year 

and inhabit backwater areas used by young native fish. These fish are capable of responding 

very quickly to favorable conditions. Impact of these non-native fish on native fish in the CRE is 

unknown, but competition, especially with young HBC, may be inferred by their occurrence in 

samples with HBC. Densities of fathead minnow (FHM), plains killifish (PKF), and red shiner 

(RSH) are highly variable in space and time, and densities are difficult to monitor. Striped bass, 

walleye, flathead catfish, and various sunfishes (bluegill, green sunfish, smallmouth and 

largemouth bass, and crappie) currently are not considered significant predators or competitors in 

Grand Canyon, possibly due to a combination of cold water and high velocities (See Survey 

Responses Section). 

Large-bodied exotic fish also may reduce recruitment of native fish through competition which is 

defined as the shared use of a limiting resource (e.g. food, space, shelter). Habitat alteration 

caused by activities of CRP was listed as a possible impact by basin researchers (Hawkins and 

Nesler 1991). Direct documentation of competition is difficult, but is suggested by native and 

non-native fishes occupying the same habitat, and by their concurrent collections in a variety of 

habitats (GCMRC unpublished data). 
Non-native Control Ad hoc Group Report 12/20/2002 

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Other concerns relate to non-native parasite introductions. Some non-native fishes (e.g. FHM 

and PKF) have been shown to carry parasites that infect humpback chub (Cole et al. 2002). 

Reduction of non-native fishes and preventing introduction of new fish species may help reduce 

transmission of parasites. Small-bodied non-natives are capable of multiple spawns per year and 

inhabit backwater areas used by young native fish. These fish are capable of responding very 

quickly to favorable conditions. In addition, anglers may illegally import small non-natives as 

baitfish and further exacerbate competition, predation and parasite impacts. 

 

STRATEGIES TO ADDRESS THE PROBLEMS 

Brown trout and rainbow trout predation

As a control strategy, AMWG has proposed a series of mechanical removals of salmonids using 

electrofishing from the Colorado River near the confluence with the Little Colorado River 

(GCMRC 2002). The project is designed to evaluate the potential effect of RBT and BNT 

predation on HBC recruitment and the efficacy of mechanical removal from the LCR inflow 

reach. 

The National Park Service is initiating a feasibility study of brown trout removal in Bright Angel 

Creek in 2002-2003. If trout removal is successful in Bright Angel Creek, National Park Service 

will consider removal efforts in other tributaries in Grand Canyon National Park (J. Cross, 

personal communication) after appropriate public input. Ongoing genetics and isotope studies 

will help to identify natal streams of salmonids, but funding for this work may need to be 

increased for more than feasibility level results to accrue. 

Broad-scale control of salmonid predators through regulation of Glen Canyon Dam releases will 

be evaluated during the experimental flows proposed for 2003-2004. This method, which 

involves increasing daily fluctuations of Glen Canyon Dam releases from January-March, is 

anticipated to reduce survival of eggs and aelvins in redds, and disadvantage fry and fingerlings 

in nearshore habitats. Determination of mortality from experimental flows and separation of 

these effects from other sources of mortality is a challenge that needs to be addressed. 

Additional broad-scale control mechanisms for coldwater salmonids are a selective withdrawal 

device on Glen Canyon Dam and manipulation of mainstem turbidity. Late summer release 

temperatures from an appropriately placed selective withdrawal could easily produce water 

temperatures downstream of Lees Ferry above 20 C, sufficiently high to cause large-scale 

mortality of mainstream salmonids. 
Non-native Control Ad hoc Group Report 12/20/2002 

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Increasing turbidity can disadvantage coldwater salmonids and other sight-dependent predators. 

Small-scale supplementation of sediment inputs below Lees Ferry, well below levels potentially 

necessary to balance the sediment budget in upper Grand Canyon may help reduce predation 

downstream. Fine sediments also might be used to choke interstices of salmonid redds, which 

could result in decreased water circulation and lowering of dissolved oxygen levels sufficient to 

cause mortality of developing embryos and aelvins. The exact mechanism for achieving this 

sediment augmentation strategy is unknown at this time. This strategy is not intended to 

adversely affect the Lees Ferry recreational trout fishery. 

Channel catfish, black bullhead and carp predation

Channel catfish, black bullhead, and common carp are, in contrast to rainbow trout and brown 

trout, warmwater fish that successfully occupy highly turbid rivers. These species are 

omnivorous and eat a variety of plant and animal matter. Carp are well-known egg predators, 

particularly of eggs from fish who deposit them in soft sediments. Catfish and bullheads are 

similar to brown trout and rainbow trout in that they become more piscivorous with increasing 

age and size. 

Little dedicated sampling of either catfish or carp has occurred under the Glen Canyon 

Environmental Studies or GCDAMP programs. Both species probably occupy the entire length 

of the Colorado River below Glen Canyon Dam, but their abundances increase with distance 

downstream from the dam probably due to warmer water. 

Evaluation of methods to control catfish and carp should be continued as part of existing 

monitoring activities in the LCR and mainstem Colorado River. Effective capture methods may 

include netting, specialized electrofishing, or angling. All channel catfish, black bullheads, 

yellow bullheads, and common carp collected in the LCR as part of long term monitoring 

activities should be removed and their gut contents examined for evidence of predation. All 

channel catfish, black bullheads and yellow bullheads collected in the mainstem Colorado River 

should be removed and their gut contents examined. Carp are collected in electrofishing catches 

in the mainstem (during two electrofishing monitoring trips in 2002 approximately 300 carp 

were captured). Removal of carp at this point seems infeasible until appropriate carcass removal 

strategies are developed. 

Competition with non-native fishes 

In ecology, competition is the interaction between two or more organisms, or groups of 

organisms, that use a common resource in short supply. Measuring competition directly is 

extremely difficult. Strategies to reduce competition may include strategies identified above, 
Non-native Control Ad hoc Group Report 12/20/2002 

Page 11 

including mechanical removal, managed flows including evaluation of high flushing flows to 

reduce small-bodied non-natives and higher daily fluctuations to reduce salmonid recruitment. 

MONITORING AND RESEARCH 

In order to assess effects of management actions on both native and non-native fishes in Glen 

and Grand Canyon an effective long-term monitoring and research program needs to be in place 

before management actions are started. The Grand Canyon Monitoring and Research is in the 

process of developing such a long-term monitoring program. Certain parts of the long-term 

monitoring program are in place and appear effective, other parts are being refined. See the 

section on Information Needs in the Appendix for our assessment of the status of progress 

towards answering Information Needs related to MO 2.6. 

We advocate that the AMWG support the following activities: 

• Continue monitoring recruitment of HBC and FMS using stock synthesis models 

(SSM) 

o GCMRC and cooperators 2000-2003. 

 New Agreements are needed for 2004-2006 

o Continue to develop SSM for BHS 

 Current data appears inadequate for conventional stock synthesis 

modeling of BHS populations. Efforts are underway to attempt to 

mark greater numbers of BHS in the LCR and other tributaries. 

o Compile and analyze available monitoring data for SPD 

 This task has not been specifically assigned, and data are somewhat 

limited. 

• Monitor population status of HBC in LCR during spring and fall. 

o GCMRC and cooperators 2000-2003 to be evaluated in 2004. 

o Continue lower 1200 m LCR long term monitoring to verify modeling efforts 

and population estimates. 

• Continue to refine monitoring efforts for native fishes in CRE. 

o GCMRC and cooperators 2000-2003. There are still monitoring difficulties 

that need to be resolved in the mainstem CRE. 

• Continue monitoring densities of adult RBT, BNT and CRP in mainstem 

o GCMRC and cooperators (thru RFP) 2000 – 2003. This part of the 

monitoring program appears adequate for assessing status and trends of RBT 

and BNT. Evaluation of CRP monitoring effectiveness needs to be continued 

through 2003. New agreements are planned for 2004-2006 
Non-native Control Ad hoc Group Report 12/20/2002 

Page 12 

• Develop methods to monitor densities of spawning and rearing BNT in Bright Angel 

Creek 

o NPS and cooperators 2002-2003. Future work will depend upon feasibility of 

weir studies conducted during winter 2002-2003. 

• Evaluate importance of tributary streams to salmonid recruitment. 

o Complete and review genetic and isotope work conducted to evaluate natal 

streams of salmonids. 

• Continue to develop methods to monitor densities of CCF and CRP in LCR and CRE 

o GCMRC and cooperators 2002-2006. 

• Ongoing monitoring activities in the LCR, investigation of other 

methods. 

• Integrate fish monitoring activities with foodbase monitoring activities. 

• Continue sampling of salmonid predators as part of GCMRC’s core monitoring 

program coupled with evaluation of gut contents during the proposed mechanical 

removal project being undertaken by Bureau of Reclamation, National Park Service, 

and U.S. Geological Survey and the National Park Service’s feasibility study of trout 

removal in Bright Angel Creek to provide information on the incidence of predation 

on native fishes. 

• Diet and food availability for both native and non-native fishes should be evaluated 

through fish and aquatic food base monitoring to assess possible competitive 

interactions. 

MANAGEMENT CONSIDERATIONS 

Timing concerns

Humpback chub may be running out of time. Populations may be approaching levels too 

low to maintain genetic diversity. Feasible management actions to control non-native 

fish need to be taken immediately. 

Social concerns

Killing fish without putting them to good use, especially in a sacred place, may be 

offensive to some stakeholders. 

• Strategies 

o Continue and expand consultation and coordination with tribes, affected 

state agencies and the public on appropriate removal options.
Non-native Control Ad hoc Group Report 12/20/2002 

Page 13 

o Disposal of carcasses needs to be conducted in a manner that provides 

some benefit. 

Anglers are concerned about possible impact on Bright Angel Creek recreational brown 

trout fishery. 

 Strategies: 

o Inform the public of AMP activities through public meetings.

o Expand outreach efforts by research and monitoring crews in the field to 

better educate the public about AMP activities.

Biological concerns

 Efforts to reduce non-native fish densities may adversely affect native fishes. 

• Strategies: 

o Ensure that monitoring data to assess status and trends of native fishes are 

collected and reported in a timely manner. 

o Assess cumulative effects of electrofishing for non-native fish capture on 

native fishes. 

o Develop methods and specific timing that reduces likelihood of negative 

impacts to native species. 

Institutional concerns

 Efforts to reduce non-native fish may fall outside the scope of the AMP. 

• Strategies: 

o Encourage appropriate agencies to seek additional funding to support and 

implement non-native control efforts. 

RECOMMENDATIONS 

The committee recommends that the Glen Canyon Dam Adaptive Management Work Group 

1. Improve public information and education efforts concerning non-native fish 

impacts on native fishes. 

Control and suppression efforts will continue to generate public interest and 

controversy. Public information and education efforts are needed to move 

forward with these efforts. 
Non-native Control Ad hoc Group Report 12/20/2002 

Page 14 

2. Evaluate methods to remove brown trout from Bright Angel Creek and consider the 

removal of rainbow trout after public input. 

Continue to encourage and support the National Park Service in these efforts. 

3. Evaluate shocking and removal of rainbow trout near mouth of the Little Colorado 

River. 

Work with GCMRC to resolve fish disposal issues. Continue core monitoring to 

cross validate efforts. 

4. Evaluate channel catfish, black bullhead and carp removal using nets and other 

appropriate methods in the Little Colorado River. 

Continue to evaluate methods for capturing catfish and carp during normal 

monitoring activities. 

5. Evaluate managed flows to disadvantage trout and other non-native fish. 

If planned experimental flows for 2003 are not implemented, follow through to 

attempt these flows in 2004. 

6. Evaluate the feasibility of a Temperature Control Device to improve humpback 

chub and native fish recruitment. 

If designed and operated adequately, a temperature control device may provide 

great flexibility in controlling both warm and cold-water predator species. 

7. Consider sediment augmentation or redistribution to benefit native fishes. 

Sediment augmentation or re-suspension of existing sediment through flow 

modification may also provide benefit to native fishes by increasing turbidity, 

which would limit the ability of sight feeding predators such as trout. 

8. Due to the urgency of the need to protect humpback chub, any feasible control 

methods should be implemented immediately. 

Evaluations of non-native control mechanisms and other actions to improve native 

fish survival and recruitment should be completed expeditiously and followed 

quickly by the appropriate management actions. Draft work plans have been 

attached for the projects that are planned for 2002-2003. 
Non-native Control Ad hoc Group Report 12/20/2002 

Page 15 

Draft Work Plans for Research and Monitoring 2002-2006 

Projects: 

1. Feasibility Study to determine the efficacy of using a weir in Bright Angel Creek to 

capture brown trout. 

2. Mechanical removal of salmonids 

3. Experimental flows to disadvantage salmonids 

4. Evaluation of catfish and carp removal methods in Little Colorado River. 

Project 1: Feasibility Study to determine the efficacy of using a weir in Bright Angel 

Creek to capture brown trout. 

Objective: Evaluate the use of a temporary weir in Bright Angel Creek to remove non-native 

salmonids from the Colorado River Ecosystem during 2002 and 2003. 

Location: Bright Angel Creek 

Project Leaders: Dr. Jeffrey Cross 

 Grand Canyon National Park 

 Bill Leibfried and Helene Johnstone, SWCA Environmental Consultants 

Period: November 2002 – February 2003 

Performance Measures: 

1. Evaluate the use of a temporary weir in Bright Angel Creek to remove non-native 

salmonids. 

2. Remove brown trout (Salmo trutta) from the Creek. 

3. Examine size, stage of sexual condition and diet of brown trout. 

4. Examine all brown trout and native fish for presence of PIT tags. 

5. Mark and release all rainbow trout (Oncorhynchus mykiss) 

6. Prepare an annual progress report and final report. 

Budget: 

 FY 2002-2003: $30,000 BOR, Contract with SWCA. 

FY 2003-2006 $562,000, National Park Service for implementation if feasible and 

after NEPA compliance 
Non-native Control Ad hoc Group Report 12/20/2002 

Page 16 

Project 2: Mechanical removal of non-native fishes (primarily salmonids) from the 

Colorado River near the confluence with the Little Colorado River.

Objective: Evaluate mechanical removal of non-native fishes. 

Location: Colorado River near confluence of Little Colorado River (River Mile 56.2 – 65.7) 

Project Leader: Dr. Steven P. Gloss 

 Grand Canyon Monitoring and Research Center 

Period: 2002 - 2006

Performance Measures: 

1. Evaluate effectiveness of mechanical removal of rainbow and brown trout by 

electrofishing. 

2. Evaluate impact of mechanical removal on humpback chub recruitment. 

3. Prepare an annual progress report and final report. 

Budget: 

 FY 2002-2003 GCMRC Est. $600,000-650,000 / year 

Project 3: Fluctuating Flows to Disadvantage non-native fishes.

Objective: Evaluate effect of experimental flow regime on non-native salmonids recruitment. 

Location: Colorado River from Glen Canyon Dam to Diamond Creek 

Project Leader: Dr. Steven P. Gloss 

 Grand Canyon Monitoring and Research Center 

Period: Experimental flows are proposed for 2003 and 2004 with ROD flows during 

2005-2006 to act as experimental controls

Performance Measures: 

1. Evaluate effectiveness of proposed experimental flow regime to reduce salmonids 

recruitment. 

a. Full experimental design has been outlined by GCMRC in their Experimental 

Flow Plan (GCMRC 2002). 

2. Prepare annual progress report and final report. 

Budget: ??? GCMRC- Appropriated funds to support experimental flows. 
Non-native Control Ad hoc Group Report 12/20/2002 

Page 17 

Project 4: Evaluation of catfish and carp removal methods in Little Colorado River.

Objective: Continue to evaluate new gear and methods to capture and monitor channel 

catfish and carp in the Little Colorado River as part of routine monitoring 

activities. 

Location: Little Colorado River near confluence with Colorado River 

Project Leaders: Arizona Game and Fish Department, U.S. Fish and Wildlife Service, other 

Cooperators 

Period: 2002 - 2006

Performance Measures: 

1. Continue to evaluate effectiveness of and test large mesh hoop nets, angling methods, 

and other methods to capture channel catfish and carp during routine monitoring 

activities. 

2. Collect diet information from all exotic fishes captured in the LCR. 

3. Prepare annual progress report and final report. 

Budget: 

 FY 2002-2003 $10-20,000 ? (BOR, AGFD) 

 We are seeking outside funding to support this work (BOR, CUP, AGFD-SWG) 

 
Non-native Control Ad hoc Group Report 12/20/2002 

Page 18 

REFERENCES 

Arizona Game and Fish Department. 1996. Ecology of Grand Canyon backwaters. Final report 

to Glen Canyon Environmental Studies, Flagstaff, AZ. Cooperative Agreement 9-FC-40-

07940. Arizona Game and Fish Department, Phoenix, AZ. 155 pp. 

Carothers, S. W. and seven other authors. 1981. A survey of the fishes, aquatic invertebrates, and 

aquatic plants of the Colorado River and selected tributaries from Lees Ferry to 

Separation Rapid. Final Report, U.S. Bureau of Reclamation Contract 7-07-30-X0026, 

Lower Colorado Region, Boulder City, Nevada. Museum of Northern Arizona, Flagstaff, 

AZ. 

Cole, R.A., A. Choudhury, and T. L. Hoffnagle. 2002. Parasites of native and non-native fishes 

of the lower Little Colorado River, Arizona 2001 Annual Report. Submitted to Arizona 

Game and Fish Department, January 2002. 

Coggins, L. G. and C. Walters. 2001. Trends in the Recruitment and Abundance of the Little 

Colorado River Population of Humpback Chub. Powerpoint presentation to Glen Canyon 

Dam Adaptive Management Program Technical Work Group, November 2001. 

(ftp://ftp.gcmrc.gov/pub/TWG/ Coggins HBC 11-01.ppt). 

Coon, K.L., Jr. 1965. Some biological observations on the channel catfish, Ictalurus punctatus 

(Rafinesque), in a polluted western river. M.S. Thesis. Utah State University, Logan.

Grand Canyon Monitoring and Research Center. 2002. Proposed two-year science plan for 

experimental flow treatments and mechanical removal activities in WY’s 2002-2004. 

Prepared for Glen Canyon Dam Adaptive Management Program, August 9, 2002. 

Hawkins, J.A. and T.P. Nesler. 1991. Nonnative fishes of the upper Colorado River Basin: An 

Issue Paper. Final Report September 30, 1991. 

Kaeding, L. R. and M. A. Zimmerman. 1983. Life history and ecology of the humpback chub in 

the Little Colorado and Colorado rivers of the Grand Canyon. Transactions of the 

American Fisheries Society 112:577-594. 

Karp, C.A. and H.M. Tyus. 1990. Humpback chub (Gila cypha) in the Yampa and Green rivers, 

Dinosaur National Monument, with observations on roundtail chub (G. robusta) and 

other sympatric fishes. Great Basin Naturalist 50:257-264. 
Non-native Control Ad hoc Group Report 12/20/2002 

Page 19 

Lentsch, L.D., R.T. Muth, P.D. Thompson, B.G. Hoskins and T.A. Crowl. 1996. Options for 

selective control of nonnative fishes in the upper Colorado River basin. Final Report 

submitted to Recovery Implementation Program. Utah Division of Wildlife Resources. 

173 pp. 

Marsh, P.C. and J.E. Brooks. 1989. Predations by Ictalurid catfishes as a deterrent to 

reestablishment of hatchery-reared razorback suckers. The Southwestern Naturalist 

34(2):188-195. 

Marsh, P. C. and M. E. Douglas. 1997. Predation by introduced fishes on endangered 

humpback chub and other native species in the Little Colorado River, Arizona. 

Transactions of the American Fisheries Society 126:343-346. 

Miller, R. R. 1968. [Unpublished field notes] 1968 Arizona collecting expedition. On file in the 

Fish Division, University of Michigan Museum of Zoology, Ann Arbor. 

Minckley, C.O. 1978. A report on aquatic investigations conducted during 1976-77 on Bright 

Angel, Phantom and Pipe creeks, Grand Canyon National Park, Coconino County, AZ. 

Report submitted to Grand Canyon National Park. Museum of Northern Arizona, 

Flagstaff. 112 pp. 

Otis, E.O. 1994. Distribution, abundance, and composition of fishes in Bright Angel and Kanab 

Creeks, Grand Canyon National Park, Arizona. M.S. thesis, University of Arizona, 

Tucson. 

Speas, D.W. 2001. Salmonid population size in the Colorado River, Grand Canyon, Arizona. 

Fishery Fact Sheet. Arizona Game and Fish Department. Prepared for the Grand Canyon 

Monitoring and Research Center. 

Speas, D.W., D.L. Ward, R.S. Rogers and W.R. Persons. 2002. Salmonid population size, 

relative density and distribution in the Colorado River in Grand Canyon during 2001 with 

reference to sampling designs for long term monitoring. Draft Annual Report submitted 

to Grand Canyon Monitoring and Research Center. November 2001 

Tyus, H.M. and N.J. Nikirk. 1990. Abundance, growth, and diet of channel catfish, Ictalurus 

punctatus, in the Green and Yampa rivers, Colorado and Utah. The Southwestern 

Naturalist 35: 188-198. 
Non-native Control Ad hoc Group Report 12/20/2002 

Page 20 

Tyus, H. M. and I. James F. Saunders. 1996. Nonnative Fishes in the Upper Colorado River 

Basin and A Strategic Plan for Their Control, Colorado River Recovery Program: 85+. 

U.S. Bureau of Reclamation. 1995. Final Environmental Impact Statement, Operation of Glen 

Canyon Dam. U.S. Department of Interior, Bureau of Reclamation, Upper Colorado 

Region, Salt Lake City, UT. 

U. S. Department of the Interior. 1999. Glen Canyon Dam modifications to control downstream 

temperatures. Plan and draft environmental assessment. U. S. Department of the 

Interior, Bureau of Reclamation, Upper Colorado Region, Salt Lake City, Utah. 

U.S. Fish and Wildlife Service. 2001. Draft Final Recovery goals for the humpback chub (Gila 

cypha) of the Colorado River Basin. 

Valdez, R.A. and R.J. Ryel. 1995. Life history and ecology of the humpback chub (Gila cypha) 

in the Colorado River, Grand Canyon, Arizona. Final Report to Bureau of Reclamation, 

Salt Lake City, Utah. Contract No. 0-CS-40-09110. BIO/WEST Report No. TR-250-08. 

256 pp. 

Valdez, R.A., and R.J. Ryel. 1997. Life history and ecology of the humpback chub in the 

Colorado River in Grand Canyon, Arizona. Pages 3-31 In: C. van Riper III and E.T. 

Deshler (eds.). Proceedings of the Third Biennial Conference of Research on the 

Colorado Plateau. National Park Service Transactions and Proceedings Series 

NPS/NRNAU/NRTP-97/12.

Valdez, R.A., B. Persons and T.L. Hoffnagle. in press. Proceedings of a Symposium and 

Workshop on Restoring Native Fish to the Lower Colorado River: Interactions of Native 

and Non-native Fishes. 13-14 July 1999, Las Vegas, Nevada. Region II, U.S. Fish and 

Wildlife Service, Albuquerque, New Mexico. 

Valdez, R.A. and S.W. Carothers. 1998. The aquatic ecosystem of the Colorado River in Grand 

Canyon. Report to Bureau of Reclamation, Salt Lake City. SWCA, Inc., Flagstaff, 

Arizona. 250 pp. 

Walters, C., J. Korman, L.E. Stevens, and B. Gold. 2000. Ecosystem modeling for evaluation of 

adaptive management policies in the Grand Canyon. Conservation Ecology 4(2):1. 

[online] URL:http://www.consecol.org/vol4/iss2/art1. 
Non-native Control Ad hoc Group Report 12/20/2002 

Page 21 

APPENDICES 

INFORMATION NEEDS

We have attempted to provide a status summary for each of the Information Needs identified in 

the Draft AMP Strategic Plan under Management Objective 2.6. This non-native control report 

needs to be fully reviewed by GCMRC. To assist in that effort we have provided a list of IN’s 

and an assessment of the status of the IN’s. 

M.O. 2.6 Reduce native fish mortality due to non-native fish 

predation/competition as a percentage of overall mortality in the LCR and 

mainstem to increase native fish recruitment. 

 

Core Monitoring Ins Status

CMIN 2.6.1 Determine and track the abundance 

and distribution of non-native predatory fish 

species in the Colorado River ecosystem and their 

impacts on native fish. 

On track for trout and carp through 

GCMRC AGFD monitoring through 

2003. Further refinement of CCF 

monitoring methods is called for. 

Research Ins 

RIN 2.6.1 What are the most effective strategies 

and control methods to limit non-native fish 

predation and competition on native fish? 

Ongoing, part of this exercise. Evaluate 

diet of RBT, BNT, CCF and CRP in CRE 

as part of long-term monitoring to 

determine predation rates. Remove all 

CCF, BBH and CRP collected as part of 

long-term monitoring activities in the 

LCR. 

RIN 2.6.2 Determine if predator suppression 

increases native fish populations? 

This IN will take several years to assess. 

Need to make sure there are enough 

replicates of treatments to separate the 

‘signal’ from the ‘noise’. 

RIN 2.6.3 To what degree, which species, and 

where in the system are exotic fish a detriment to 

the existence of native fish through predation or 

competition? 

Ongoing, part of this exercise. 

RIN 2.6.4 What are the target population levels, 

body size and age structure for non-native fish in 

the Colorado River ecosystem that limits their 

levels to those commensurate with the viability of 

native fish populations? 

This may be a modeling exercise. We 

don’t have the information needed to 

answer this question. 

RIN 2.6.5 What are the sources (natal stream) of 

non-native predators and competitors? 

Ongoing, Philipp genetics work, 

Michigan isotope analyses. 

RIN 2.6.6 What are the population dynamics of 

those non-native fish that are the major predators 

of native fish? 

At present major predators appear to be 

brown trout, ictalurids (including channel 

catfish and black bullhead) and rainbow 

trout. Brown trout and ictalurids may be 

dependent on tributary spawning whereas 
Non-native Control Ad hoc Group Report 12/20/2002 

Page 22 

rainbow trout spawn in the both 

coolwater tributaries and the mainstem 

Colorado River. Other aspects of 

population dynamics should be reviewed. 

Effects Monitoring Ins

EIN 2.6.1 How does the abundance and 

distribution of non-native predatory fish species 

and their impacts on native fish species in the 

Colorado River ecosystem change in response to 

an experiment performed under the Record of 

Decision, unanticipated event, or other 

management action? 

Ongoing, will take replicated experiments 

and long term monitoring. 
Non-native Control Ad hoc Group Report 12/20/2002 

Page 23 

Technical Work Group ad hoc members:

Bill Persons 

Arizona Game and Fish Department 

2221 West Greenway Road 

Phoenix, Arizona 85023 

(602) 789-3375 

bpersons@gf.state.az.us

Gary L. Burton 

P.O. Box 281213 

Lakewood, CO 80228-8213 

(720) 962-7259 

burton@wapa.gov

Kerry Christensen 

(928) 769-2254 

cuszhman@yahoo.com

William Davis 

Ecoplan Associates 

701 W Southern Ave Suite 203 

Mesa, AZ 85210 

(480) 733-6666 

bdavis@ecoplanaz.com

Steven Gloss 

Grand Canyon Monitoring and Research 

Center 

2255 N. Gemini Drive 

Flagstaff, AZ 86001 

(928) 556-7069 

sgloss@usgs.gov

Christopher Harris 

770 Fairmont Avenue 

Suite 100 

Glendale, CA 91203-1035 

(818) 543-4676 

csharris@crb.ca.gov

Norm Henderson 

(520) 608-6272 

norm_henderson@nps.gov

Pamela Hyde 

P.O. Box 1845 

Flagstaff, AZ 86002-1845 

(928) 214-6492 

pam@southwestrivers.org

Dennis Kubly 

125 S. State St. 

Salt Lake City, UT 84138-1102 

(801) 524-3715 

dkubly@uc.usbr.gov

Ted Melis 

(928) 556-7282 

tmelis@usgs.gov

Andre Potochnik 

(928) 773-1075 

arp4@mail.infomagic.net

Nikolai Ramsey 

2601 N. Fort Valley road 

Flagstaff, AZ 86001 

(928) 774-7488 

ramsey@grandcanyontrust.org

Mike Yard 

GCMRC 

(928) 556-7374 

myard@usgs.gov
Summary of committee work done

 Members of the committee held a conference call (24 September 2002) to elect a chair, 

discuss the assignment from the AMWG, and review a preliminary outline of the committee 

report prepared by the previous chair (Rick Johnson). The group agreed to continue working on 

the report. A revised outline was prepared by the Chair and distributed on September 27th. 

Comments were received from one member of the group on October 7, and a second draft of the 

report was distributed on October 9, 2002. No further comments were received by October 15, 

2002, so the chair proceeded with the outline as presented. 

The chair also prepared a non-native fish control strategy matrix survey for review by the 

committee prior to sending it to members of the Native Fish Work Group and fish biologists 

working in Glen and Grand Canyons. The survey was designed to help evaluate feasibility of 

different control strategies for non-native species perceived as threats. The survey was sent to 

approximately 30 fisheries workers on October 7, 2002, and returned by 11 persons. Results of 

the matrix survey are presented. The working members of the committee met on November 6, 

2002 to review the charge, the draft outline and to assign sections of the report for completion by 

November 22, 2002. The chair presented a status report at the TWG meeting on November 8 

with a revised schedule for completion. The working members of the committee held a 

conference call on November 21, 2002 to discuss final changes to the draft. A draft report was 

E-mailed to the full TWG on November 22 with comments due back to the chair on December 

11. Comments were received from several reviewers and incorporated into the final draft report 

that was E-mailed to the TWG on December 17. A TWG phone poll was held on December 20 

to recommend forwarding the final committee report to the AMWG on December 27with minor 

changes suggested by the group. 
Copy of cover letter sent with non-native fish control matrix survey.

October 7, 2002 

On behalf of the non-native control group ad hoc committee, Glen Canyon Dam Adaptive 

Management Program Technical Work Group, we are conducting an informal survey of fishery 

biologists and other persons familiar with the Colorado River to assess perceived threats to the 

native fish community. We are asking your assistance in completing a brief survey to assess 

species that pose the greatest threat to native fishes and an assessment of possible control 

techniques for those species. By “control” we mean reducing the non-native fish sufficiently 

to benefit the native species of concern (primarily humpback chub). 

In the attached spreadsheet, please: 

1. Rank the listed species in order of perceived threat to native species, with 1 being the 

highest threat. 

2. For each combination of species and control technique, assign a rank from 1 to 10 

according to the expected effectiveness of the control technique in suppressing the target 

species impacts in the Colorado River Ecosystem (from Glen Canyon Dam to the western 

boundary of GC National Park). A rank of 1 means the control technique is expected to 

be highly effective; a rank of 10 means the control technique is expected to not be very 

effective. Leave a cell blank to indicate that a particular technique is not thought to be 

applicable for control of a particular species. This table is intended as a basis for 

discussion. Feel free to amend or add comments. 

3. List other possible control methods you think might be effective, either in the indicated 

column, or in separate text accompanying your response. 

4. List additional species that you perceive to be a threat in the supplied row or in separate 

text accompanying your response. 

Feel free to contact me if you have any questions about this exercise. Responses will be 

summarized for presentation to the Technical Work Group and the Adaptive Management Work 

Group in a committee report, in November 2003. If you would like a copy of the committee’s 

report please let me know and I will be sure and send you one. 

Thanks in advance for your response. 

Please return the spreadsheets (preferably by Email) by October 18, 2002 to: 

Bill Persons 

Research Program Supervisor 

Non-native control ad hoc group chairperson 

bpersons@gf.state.az.us <mailto:bpersons@gf.state.az.us>

(V) 602-789-3375 

(F) 602-789-3918 
Non-native Control Ad hoc Group Report 12/20/2002 

Page 26 

Copy of control matrix distributed to select individuals

1. Please rank the listed species in order of perceived threat to native fish in column B.

2. For each combination of species and control technique, assign a rank from 1 to 10 according to the 

expected effectiveness of the control technique in suppressing the target species impacts in the Colorado 

River Ecosystem (from Glen Canyon Dam to the western boundary of GC National Park). Rank of 1 

means the control technique is expected to be highly effective; a rank of 10 means the control technique is 

expected to not be very effective. Leave a cell blank to indicate that a particular technique is not thought 

to be applicable for control of a particular species. This table is intended as a basis for discussion. Feel 

free to amend or expand it as needed. 

Control Techniques 

Species 

Rank in order 

of perceived 

threat to 

native fish (1 

= highest 

threat,16 = 

lowest)

Electrofish

ing or net 

Traps or 

weirs Seine 

Chemical 

(1) 

Managed 

flow (2) 

Temperatu

re Control 

Other control methods 

(please list) 

Black bullhead 

Black crappie 

Bluegill 

Brown trout 

Channel catfish 

Common carp 

Fathead minnow 

Green sunfish 

Largemouth bass 

Plains killifish 

Rainbow trout 

Red shiner 

Smallmouth bass 

Striped bass 

Walleye 

Yellow bullhead 

Additional 

(1) Target spawning aggregations or other isolated assemblages. 

(2) Primarily refers to increased daily fluctuations, can include flushing flows, low flows, sediment suspension flows, habitat

disruptive flows. They may each be unique in timing, duration, and release form. 

Control techniques applicable for target nonnative fish species. Based on Lentsch et al. 1995 in Tyus and Saunders 1996. 

Please return completed sheet to: 

Bill Persons 

Arizona Game and Fish Department 

2221 W. Greenway Road 

Phoenix, AZ 85023 

bpersons@gf.state.az.us
Non-native Control Ad hoc Group Report 12/20/2002 

Page 27 

Names of survey participants

Emailed survey Responded 

Bill Davis, Ecoplan Associates X 

Dennis Kubly, BR X 

Gary Burton, WAPA X 

Dennis Stone, USFWS X 

Dave Speas, AGFD X 

David Ward, AGFD X 

Scott Rogers, AGFD X 

Scott Reger, AGFD X 

Melissa Trammell, SWCA X 

Rich Valdez X 

Bill Persons, AGFD X 

Paul Marsh, ASU x 

Rob Clarkson, BR x 

Andre Potochnik, GCRG 

Chris Harris, CRBC 

Dave Foster, Marble Canyon Guides 

Jeffrey Cross, NPS 

John Shields, Wyoming 

Kerry Christiansen, Hualapai Tribe 

Mike Yard, GCMRC 

Nikolai Ramsey, Grand Canyon Trust 

Norm Henderson, NPS 

Pam Hyde, Southwest Rivers 

Rick Johnson 

Steve Gloss, GCMRC 

Ted Melis, GCMRC 

Pam Sponholtz, USFWS 

Randy Van Haverbeke, USFWS 

Andy Makinster, AGFD 

Michael Douglas, CSU 

Lew Coggins, GCMRC 

Josh Korman, Ecometrics 

Carl Walters, UBC 

Tony Robinson, AGFD 

Rob Bettaso, AGFD 

Steve Carothers 

 

X = Completed survey, x = commented but did not 

complete survey 
Non-native Control Ad hoc Group Report 12/20/2002 

Page 28 

Ranking of perceived threat of nonnative species to native species by control survey matrix 

respondents. Low ranking indicates highest perceived threat. 

Perceived Threat (1 = High, 10 = Low Threat)

0 5 10 15 20

Brown trout

Rainbow trout

Channel catfish

Common carp

Red shiner

Yellow bullhead

Fathead minnow

Black bullhead

Green sunfish

Largemouth bass

Striped bass

Walleye

Smallmouth bass

Black crappie

Bluegill

Plains killifish

Species

Mode of responses
Non-native Control Ad hoc Group Report 12/20/2002 

Page 29 

Median rankings of control measures by species. Low numbers indicate control technique is 

expected to be effective, high numbers indicate control technique is expected to be relatively 

ineffective. 

 

Electrofishing 

or net 

Traps 

or weirs Seine 

Chemical 

(1) 

Managed 

flow (2) 

Temperature 

Control 

Black bullhead 7.5 5.5 6.5 8 8 7 

Black crappie 5 5 7 5 5 5.5 

Bluegill 5 5 8 5 5 5 

Brown trout 3 4 8 3 4 5 

Channel catfish 7 5 8 5 7.5 5 

Common carp 4 5 7 3.5 7 7.5 

Fathead minnow 8 5 6 5.5 4.5 6.5 

Green sunfish 6 6 7 5 5 5 

Largemouth bass 5 6 7 5 5 5 

Plains killifish 8 5 5 2.5 5 5 

Rainbow trout 3 5 8 4 3 4 

Red shiner 8 5 5 4 4.5 6 

Smallmouth bass 5 7 7.5 5 6.5 5 

Striped bass 6 8 9 7 6 4 

Walleye 5 6 9 6 6 6 

Yellow bullhead 8 5.5 8.5 7 8 7 

Table Total 5 5 8 5 5 5 

Sum 98.5 93 124.5 85.5 95 93.5 
Non-native Control Ad hoc Group Report 12/20/2002 

Page 30 

Additional comments received from survey participants: 

Attached is my first cut at the ranking sheet. Thanx for all your work getting this up and going. Regarding my 

conclusions: from this exercise, it becomes very apparent, temperature control suppresses the most species and the 

most; yet, we wish to throw this out to enhance the humpback chub. Perhaps, finding a way to suppress the few cold 

water species would be the most effective and result in improved survival of LCR humpback chub. It seems 

anything we do to try and enhance river survival for humpback will result in a multitude of other warm water 

species jumping on the band wagon regardless of our efforts to control the beneficial effects or target them only to 

humpback. The table demonstrates there are many warm water species that may pose a problem yet only a couple 

cold water species and these latter may be amenable to some control. 

Bill Davis 

A good attempt at getting some input on this type of problem, but I found it impossible to fill out your table because 

too many assumptions were ambiguous. For example, if you were looking for input on existing conditions, most of 

the fishes listed are not even present. If you were looking for input on what the fauna could look like following 

implementation of TCD, species such as rainbow trout presumably would not be a problem, at least in the LCR area 

and below. I'm afraid all I can do is list some general conclusions with multiple caveats. 

In general, I believe green sunfish is the single most problematic species in the Gila basin, followed by red shiner 

and maybe smallmouth bass and the catfishes (including flathead). These species, if introduced to Grand Canyon, 

could become serious problems for natives following implementation of TCD. Obviously the two trouts and 

channel catfish seem to be the most problematic at present, however. For electrofishing, I doubt any significant 

population control could be gained except perhaps for the small-bodied fishes that reside in backwaters and 

nearshore areas, and maybe rainbow trout. The same (minus trout) holds for seining and maybe minnow trapping. 

Other trapping could be practical in certain tributaries, but I found I could not lump the mainstem and tribs into a 

single analysis due to their obvious physical differences. I doubt that chemical control is viable except if practiced 

system-wide. For example, TFM (lampricide) is highly selective against ictalurids (but not currently registered for 

use outside of the Great Lakes basin), and could be temporarily effective if administered at the headwaters on down. 

Similarly, an entire river-wide renovation with rotenone, followed by repatriation of natives, could effect significant 

population control of all non-native species, but such a scenario appears unlikely as an alterative at present. I 

considered that honking floods (>>50,000 cfs) could be effective against at least the small-bodied species and 

perhaps others, but that scenario doesn't look likely either. Daily fluctuations have been shown to kill a portion of 

rainbow trout spawn (and some adults), but such fluctuations have negative effects on other resources. 

I continue to believe that TCD remains the best alternative for species control. Warming will immediately suppress 

downstream trout populations. If after some years of warming other non-native populations grow to undesirable 

levels, the warm water could be turned back off for a year or two to destablize the warmwater species. At least the 

natives will get off periodic mainstem spawns before one or the other nonnative group takes over. 

Finally, if temperature control is implemented, stocking of squawfish might serve to suppress some populations (and 

might even if TCD is not implemented). 

Sorry that I was unable to compartmentalize this stuff for you a little better. I will be interested in seeing how you 

summarize the input from others that might give you feedback. Good luck. 

Rob Clarkson 

Rob: Well, you pretty much said it all, and certainly expressed my thoughts on the matter. Bill -- I'm quite in 

agreement with Rob, and thus won't attempt to fill out the table. In fact, I tried and found that most of the entries 

were left blank -- the situation is just too complex and there are too many impinging variables. I'm not even sure 

what was intended as the baseline or geographic scope. Like your matrix, fish control in Grand Canyon is not a 

trivial matter, and it might be easier to approach the problem incrementally by addressing one question at a time, 

through which process all of the caveats, constraints, conflicts and assumptions could be identified and addressed. 
Non-native Control Ad hoc Group Report 12/20/2002 

Page 31 

In this approach, the individual species is perhaps the most useful incremental unit. Thanks for working on this, 

Bill. It is important. Paul Marsh/ 

Additional Comments received: 

Comments from control techniques survey. 

 

Respon

dent: 

Species or 

method: Comment 

R6 

Electrofishing 

or net EF effective for large bodied fish, probably better off with a seine for small ones 

R6 Traps or weirs 

mainchannel catch rates low during clear water; weir effective if tributary is significant 

recruitment source. 

R6 Seine 

See SWCA predator removal reports for efficiency of backwater seining. Not much 

promise for mechanical removal of cyprinids in upper basin, although catchability of same 

in backwaters is high. Maybe work in lower basin because they are restricted to 

backwaters? 

R6 Chemical (1) I never thought this was an option, but LCR seems to be the only area it might work. 

R6 

Managed flow 

(2) Model say hi for RBT; others???? 

R6 

Temperature 

Control Likely a biological disaster; may limit RBT, but will just invite browns up to LCR region. 

R6 Common carp vegetated shallows in LCR; risk of killing HBC larvae 

R5 Black bullhead Upstream selective passage migration barrier 

R5 Black crappie Screen pond/reservoir outlets 

R5 Bluegill Screen pond/reservoir outlets 

R5 Brown trout Upstream selective passage migration barrier 

R5 Green sunfish Screen pond/reservoir outlets 

R5 

Largemouth 

bass Screen pond/reservoir outlets 

R5 Rainbow trout Upstream selective passage migration barrier 

R5 Striped bass Upstream selective passage migration barrier 

R5 Walleye Screen pond/reservoir outlets 

R9 1. I assumed present conditions and relative abundances for my rankings. 

R9 

2. An increase of temperatures would drastically change rankings of potential threat. It 

would also change relative effectiveness and applicability of different control methods 

R9 

3. You might want to consider asking folks to do a revised ranking with the assumption of a 

specific temp increase. 

R9 

As I ranked fish I tried to consider relative abundance, predation, resource overlap, and 

sympatry. 

R9 4. I inserted comments on some of the methods 

R9 

5. A feasibility study we did for nonnative control methods in Utah lake to benefit the June 

sucker suggested that combinations of methods work best, e.g., for brown trout, you would 

want to both remove by electrofishing and weirs, and possibly even chemical treatment. 

R9 

6. Targeting the fish when most vulnerable is desired. Generally, when in spawning 

aggregations or as young juveniles. 

R9 

Electrofishing 

or net 

not considered for NN rank>9. Assumes includes trammel nets , hoop nets, minnow traps, 

fyke nets, slat traps, etc. 

R9 

Traps or weirs - 

black bullhead incidental to channel catfish removal efforts 

R9 Traps or weirs assumes only includes temporary or permanent weirs on tributaries 
Non-native Control Ad hoc Group Report 12/20/2002 

Page 32 

R9 Seine 

This did not work in upper basin due to high reproduction, however, in temp limited GC may 

be more effective. 

R9 Chemical (1) 

assumes chemical treatment would only be used in tribs where no HBC occur, or in LF 

reach (sorry!) 

R9 

Chemicals, 

rainbow trout 

probably ineffective to treat tribs due to mainstem spawning, treating LF reach would be 

very risky not to mention controversial 

R9 

Chemicals, 

carp could be treated in some areas, but most are near LCR and chubs 

R9 

Temperature 

cntl (maintain) 

brown trout Keeps them mostly downstream of LCR 

R9 

Temp control 

increase BNT small increase could expand distribution upstream, larger increase could reduce 

R9 

Additional 

Species Shark 

R8 

Other control 

methods 

(please list) 

Watershed mgmt (assessments, stocking controls, local removal, and interception) should 

be components for most nonnatives, but particularly for small-bodied, rapidly spreading 

species 

R8 

Other control, 

channel catfish Angling, Trot lines------3 

R8 

Other control, 

carp Angling, Trot lines------4 

R10 Other method 

Barrier to upstream movement near lake mead (low head dam, or electric barrier) in 

combination with a TCD 

R11 Bullheads Slat traps 

R11 Channel catfish CC Virus?, Concentrated Angling? 
Non-native Control Ad hoc Group Report 12/20/2002 

Page 33 

FIGURES 

Figure 1. Estimated humpback chub recruitment and rainbow trout catch per 10 hours of 

electrofishing near the mouth of the LCR. 

Estimated Humpback Chub Recruitment versus Rainbow Trout CPUE

0

5000

10000

15000

20000

25000

30000

35000

40000

45000

50000

198919901991199219931994199519961997199819992000

Brood Year

Humpback Chub Recruitme

n

0

100

200

300

400

500

600

 RBT CPUE (Fish/10 hours

Supertag

RBT CPUE
Non-native Control Ad hoc Group Report 12/20/2002 

Page 34 

Figure 2. Estimated humpback chub recruitment and brown trout catch per 10 hours of 

electrofishing near the mouth of the LCR. 

Estimated Humpback Chub Recruitment versus Brown Trout CPUE

0

5000

10000

15000

20000

25000

30000

35000

40000

45000

50000

198919901991199219931994199519961997199819992000

Year

Humpback Chub Recruitment

0

2

4

6

8

10

12

14

 BRT CPUE (Fish/10 hours)

Supertag

BRT CPUE