TECHNICAL WORK GROUP AD HOC COMMITTEE REVIEW

OF

AQUATIC PEP RECOMMENDATIONS REPORT

Gary Burton, Bill Davis, Steve Gloss, Rick Johnson, and Dennis Kubly 

The Technical Work Group Aquatic Protocol Evaluation Panel Review Ad hoc Committee (Ad 

hoc) was very impressed with the Aquatic Protocol Evaluation Panel’s (PEP) knowledge and 

background and we greatly appreciate their efforts. We encourage continued efforts to bring 

fresh ideas into the Glen Canyon Dam Adaptive Management Program (GCDAMP), and we 

applaud the Grand Canyon Monitoring and Research Center’s (GCMRC) efforts to continue 

these reviews. Hopefully, the use of PEPs will be an ongoing process and continue to help the 

GCDAMP in improving the program’s research and monitoring efforts. 

The PEP report authored by Anders and others (2001)1

 contains recommendations and comments 

directed at six major programmatic areas in the aquatic program. These areas are (1) 

establishment of a water quality program (2) conducting a critical review of the food base 

program (3) expansion of research and monitoring for humpback chub (4) development of a 

monitoring plan for other native fish (5) extension of exotic fish monitoring to nonsalmonid 

species and (6) program management. 

The process engaged in by the Ad hoc followed that agreed to by the Technical Work Group 

(TWG) at their March 14-15, 2001, meeting. In this process GCMRC responds to the PEP 

recommendations and the TWG subsequently reviews both the PEP report and GCMRC 

responses and provides concurrence or other recommendations. GCMRC then develops revised 

long-term and annual plans based on TWG comments. If necessary, GCMRC seeks additional 

feedback from the PEP chair in addressing TWG comments. Finally, GCMRC and the TWG 

make joint recommendations for revised research and monitoring plans to the AMWG. 

Establish a Water Quality Program 

PEP Recommendation: A water quality program that monitors physical and biological 

parameters of the Colorado River in Grand Canyon should be established. This program could be 

tied to physical sampling sites at non-boat access points associated with USGS gauging stations. 

GCMRC General Response: GCMRC generally agrees with this recommendation. However we 

are moving at a deliberate pace which parallels our revision of the IWQP as well as changes in 

our foodbase monitoring and research program. We want water quality measurements and 

programs to be linked in a meaningful way to other elements of our program, including physical 

resources. 

Ad hoc Response: The Ad hoc agrees that a comprehensive water quality program needs to be 

defined and implemented, and that this program should be linked to the physical, food base, and 

fisheries sampling. We also agree that the reservoir water quality sampling should not stand 

alone, but rather be linked to that of the downstream Grand Canyon ecosystem, and that the 
Review of Aquatic PEP Recommendations May 10, 2002 

TWG Ad hoc Aquatic PEP Review Committee Page 2 

primary emphasis for water quality should be downstream as identified by the earlier Integrated 

Water Quality Protocol Evaluation Panel. It is important to learn the characteristics, variability 

and effects of the medium we seek to understand. It is also important to understand the limits to 

which we can influence those characteristics and set priorities accordingly. 

The water quality program should preferably go through similar data synthesis and analysis to 

that of fish program before we embark on a new long-term monitoring program. The committee 

thinks it would be helpful for GCMRC to provide results of these analyses to the TWG, 

including identification of variables being measured, detection limits, and precision of estimates 

expected from the planned frequency and intensity of sampling. This information will assist in 

any sequencing or prioritization necessary to meet future budgetary constraints should they arise. 

The Ad hoc agrees with GCMRC that one impediment to identifying the variables to be 

measured in the water quality program is the lack of finalized management objectives and 

information needs. The PEP did identify some variables that they believed would be included in 

any water quality program. Among them were turbidity, water temperature, key nutrients, and 

carbon. They suggested beginning regular temporal sampling at the four physical program sites 

(Lee’s Ferry, Paria River, Bright Angel Creek and Diamond Creek) and at the mouths of 

tributaries on at least a seasonal basis. It was not clear to the Ad hoc whether some water quality 

sampling at the four gaging sites already is being completed by USGS staff contracted to gather 

flow and sediment data at these sites. 

GCMRC has initiated some water quality sampling, including forms of organic carbon in 

conjunction with collection of drift for the food base program, water temperature, and 

conductivity data, at the four fixed physical program sites. GCMRC identifies the carbon 

sampling as being pursuant to the development of a carbon budget, but it is not apparent whether 

the identified sampling regime includes necessary carbon inputs at Glen Canyon Dam and from 

tributaries. The Ad hoc notes that development of a carbon budget for the CRE undoubtedly 

would require much more extensive sampling, both temporally and spatially, than is presently 

being conducted by GCMRC. Also, it is not clear to us that the PEP intended this sampling to be 

more than part of the standard monitoring program. We request that GCMRC identify the 

necessary sampling and estimated cost to develop a carbon budget for the CRE so that the TWG 

can be advised of the cost of completing this task. 

The PEP includes key nutrients as important water quality variables in their recommendation, but 

notes that these variables, forms of nitrogen and phosphorus, have in the past not been measured 

with sufficient resolution. The PEP notes that there are techniques available to measure nutrients 

at desired levels and recommends that they be initiated by GCMRC. GCMRC indicates that they 

will improve this sampling to the level of resolution advocated by the PEP, and the Ad hoc 

concurs with that response. As with other variables being measured in this program, the Ad hoc 

thinks it would be beneficial for GCMRC, as the science institution, to convey to the TWG, as 

the interface with the AMWG, the statistical power available for detecting spatial and temporal 

change in the proposed sampling design.
Review of Aquatic PEP Recommendations May 10, 2002 

TWG Ad hoc Aquatic PEP Review Committee Page 3 

Conduct a Critical Review of the Foodbase Program 

PEP Recommendation: The food base program needs to be critically reviewed because the 

current level of understanding about the linkages between lower trophic levels and food 

availability of native fishes is not adequate to interpret food base data in relation to the 

management goal. Lower trophic levels can also be used to monitor ecosystem changes. 

GCMRC needs to explicitly identify the goal of the food base program, determine what metrics 

to use to monitor the lower trophic levels, and decide what level of detection of change is 

required. Sufficient data and experience exists to design a program that meets the identified 

needs with appropriate power. 

GCMRC General Response: GCMRC fully concurs with this recommendation and we are in the 

process of redesigning our foodbase monitoring. This process will likely evolve over the next 

two-three years and involve articulation with the IWQP and fisheries research and monitoring 

efforts. Level of taxonomic resolution and intensity of sampling as well as budget and program 

linkages will be considered. 

Ad hoc Response: The PEP advocated this critical review because “the current level of 

understanding about the linkages between lower trophic levels and food availability of native 

fishes is not adequate to interpret food base data in relation to the management goal.” The PEP 

also advised that “[s]ufficient data and experience exists to design a program that meets the 

identified needs with appropriate power.” The Ad hoc is somewhat concerned that the PEP did 

not consider the Lee’s Ferry reach in their analysis of foodbase data as those data are extensive 

and their inclusion may have affected the PEP’s recommendations on this program. 

The Ad hoc agrees that GCMRC should conduct the critical review of the foodbase program, 

including a power analysis to determine what detection limits can be realized with existing and 

proposed sampling designs. GCMRC indicates that they have already modified the sampling 

regime for benthic monitoring by increasing the number of benthic sites and the number of 

samples on hard substrates, while eliminating the sampling of pool habitats. This information 

was valuable to the Ad hoc, but it does not include how sampling sites are being selected, 

whether they are at fixed or random locations, whether the frequency and timing of sampling has 

changed, and what level of precision is anticipated with the prescribed sampling regime. Also, 

GCMRC indicates that they are evaluating data for the ability to determine a 5-year trend, but the 

experimental design for experimental flows presently under consideration is a blocked design 

that may not lend itself to measurement of 5-year trends. We advocate that GCMRC 

communicate to the TWG what statistical analyses they anticipate using to determine change in 

status or trend for measured variables and what power the tests will have for detecting change in 

these variables. 

As identified by the PEP, one approach to ascertaining the energy sources from lower trophic 

levels actually incorporated into fish tissue is to use naturally occurring isotopes. Some work 

using this approach has already been accomplished in the Colorado River ecosystem. We 

understand GCMRC’s hesitation in making additional commitments for funding isotope 

research, but at the same time we did not find a suggested approach in their response that can 
Review of Aquatic PEP Recommendations May 10, 2002 

TWG Ad hoc Aquatic PEP Review Committee Page 4 

identify the unknown linkages between the food base and fish bioenergetics. We advocate that 

GCMRC give further consideration to how these linkages can be determined. 

 

The PEP identified that information on lower trophic levels in the AMP is treated for its value as 

regards food for fish, rather than as an indication of the health of the CRE. They noted that the 

use of algae and invertebrates as indicator species would require taxonomic identification at a 

level beyond that accomplished by monitoring in the present program. Recent discovery of the 

exotic New Zealand mudsnail suggests that additional emphasis on determining the identity of 

algae and invertebrates may well be warranted, particularly if, as now suspected, the species has 

been present for more than two years without being detected. The Ad hoc suggests that GCMRC 

should confer with Glen Canyon National Recreation Area and Grand Canyon National Park to 

determine whether these two Park Service units have a program for detecting invading exotic 

species. If such a detection system does not exist, the GCDAMP should determine through its 

information needs process whether this emphasis is important to the program. As indicated by 

the PEP, we concur that linkage to the water quality program would be important for any lower 

trophic levels indicators. 

Expand the Research and Monitoring for Humpback Chub 

PEP Recommendation: The PEP recommends that further work be conducted to develop a 

conceptual model of the metapopulation biology of chub in the GCE to provide a context for a 

long-term monitoring program. Consideration should be given to the inclusion of genetic 

concerns in the monitoring program. GCMRC needs to develop explicit linkages between the 

results of annual monitoring and the management goals to ensure that the monitoring programs 

produce results appropriate to review progress to the goals. The PEP supports the completion of 

the current review of existing data, and the development of population models as these programs 

will yield sufficient information to make decisions about sampling programs for chub. 

GCMRC General Response: GCMRC has funded and awaits the results of both a genetic study 

and isotopic analysis of tributary stream systems which should help resolve the metapopulation 

and attendant management/monitoring questions associated with this. We are developing a 

biannual feedback process to TWG and AMWG on monitoring results. 

Ad hoc Response: The Ad hoc committee supports the completion of the genetic study on 

humpback chub, particularly with the recent emphasis by the AMWG on establishing a refugium 

population and the continuing questions on genetic identity of mainstem aggregations. The 

metapopulation biology of Grand Canyon humpback chub is an issue that needs to be addressed 

as regards its genetic diversity and integrity. We also agree with the PEP that isotopic analyses 

could be very valuable in determining natal streams and, perhaps, in differentiating time spent by 

individuals in the mainstem and tributaries. The Ad hoc supports GCMRC’s compilation and 

evaluation of historic data, and we look forward to hearing the results of this effort. 

Much of GCMRC’s effort in tracking humpback chub is directed at use of stock assessment for 

determining recruitment. Unfortunately this index can not be used until the fish are at the age of 

recruitment, which is age 3-4, and the fish will suffer varying mortality to this age under a 

variety of flow regimes. The PEP recognized this difficulty in the context of assessing effects of 
Review of Aquatic PEP Recommendations May 10, 2002 

TWG Ad hoc Aquatic PEP Review Committee Page 5 

dam operations on fish at the age of recruitment when those operations varied annually. In 

related advice, the PEP advocated that GCMRC reanalyze the backwater (early life stage) fish 

data with the express goal of evaluating the utility of this information as a real-time recruitment 

index. The Ad hoc supports the PEP’s recommendations that data on early life stages of native 

fish in mainstem rearing habitats should be reanalyzed, and we advocate that GCMRC should 

provide or present that analysis to the TWG for its consideration. 

Develop a Monitoring Plan for other Native Fish 

PEP Recommendation: The PEP was concerned that there no plan for monitoring the status of 

the 3 other extant native fish of the GCE. The PEP supports the ongoing synthesis of existing 

information and attempts to develop a population model for flannelmouth sucker as the first steps 

for developing a program for this species. GCMRC should develop explicit linkages between 

management goals and monitoring programs, and once all available data for the non-native 

species have been assembled, review options for monitoring these species. 

GCMRC General Response: GCMRC shares this concern but has been limited by resources and 

available personnel. We have increased our efforts recently with respect to flannelmouth sucker 

and will do so on other species as soon as feasible. The GCMRC fisheries cooperators have held 

discussions regarding synthesis of available information and increased efficiency of monitoring 

efforts in relation to management goals. 

Ad hoc Response: The Ad hoc shares the PEP’s concern for studies of other native fish and we 

support efforts to track these species’ status and trends. Approaches being used for humpback 

chub should also have application with at least flannelmouth sucker and bluehead sucker. 

Extend Exotic Fish Monitoring to Non-salmonid Species 

PEP Recommendation: For the CRE below Lee’s Ferry, the management goals for non-native 

fish are related to their impacts on native species. The PEP was impressed by the efforts to 

develop a program to estimate the abundance of salmonids in the Colorado River, but felt some 

effort should be (re-)allocated to the other components of risk to native species, especially with 

respect to predation. There is no explicit program for warm-water exotic fish species. The PEP 

suggests that the species should be ranked for their potential for impacting native species, and 

that monitoring metrics be developed for the important species that address potential risk to 

native fish. Thorough analysis of available data should assist in the evaluating the feasibility of 

monitoring programs for these species. 

GCMRC General Response: GCMRC shares these concerns and will address these issues as 

resources permit. We have begun a more focussed monitoring effort to delineate the distribution 

on non-native species. Similarly we have targeted programs planned for FY02 and FY03 to 

gather more reliable data regarding predation on native fish by non-natives in the LCR and 

mainstem CR near the LCR. 

Ad hoc Response: The Ad hoc agrees with the PEP recommendation to expand the fish 

monitoring to warmwater non-native fish species. We believe, however, that a preliminary 
Review of Aquatic PEP Recommendations May 10, 2002 

TWG Ad hoc Aquatic PEP Review Committee Page 6 

analysis by GCMRC to prioritize species and habitats should be accomplished because the 

budget for this program has limits. This analysis should give consideration to the degree of 

negative interactions between native and non-native fish species. Given these considerations, we 

advocate that this expansion of emphasis be given serious consideration in the sequencing of 

information needs by the TWG and in the resulting recommendations sent to the AMWG. 

Management Issues 

PEP Recommendation: The PEP observed considerable variation in the analytical effort 

expended, the timeliness of reporting, and the availability of standardized databases among 

programs for aquatic resources. A standardized annual reporting cycle is a key component of any 

monitoring program. The PEP recommends that the contracting process needs to be much more 

tightly controlled, and wonders whether greater ‘in-house’ capability is required at GCMRC to 

achieve long-term consistency and quality in the monitoring program. 

GCMRC General Response: GCMRC concurs with both this concern and the recommendation. 

We have begun development of a standardized database and reporting procedure/requirement. 

We will develop consistent reporting requirements for external awards in the biology program. 

This has already been done with regard to the fisheries monitoring effort and GCMRC is 

developing (as stated above) an explicit feedback process for monitoring results to AMWG. 

Ad hoc Response: The Ad hoc concurs with the PEP and GCMRC that standardized and timely 

reporting, along with standardized data entry and database formats, will benefit the program. It 

also makes sense to us that longer term contracts will lend a greater consistency to information 

collection and help to assure meaningful results. These longer term contracts can be made 

conditional on satisfactory performance, and we urge GCMRC to maintain a quality assurance 

element in their programs to ensure this performance is achieved. 

1

 Anders, P., M. Bradford (Chair), P. Higgins, K.H. Nislow, C. Rabeni, and C. Tate. 2001. Draft 

report of the Aquatic Protocol Evaluation Program Panel. Report to Grand Canyon 

Monitoring and Research Center, Flagstaff, Arizona. November 28, 2001.