Development of Fish monitoring (Electrofish

Trends in the Grand Canyon Fish Commun
History and development of long-ter

• In 1999 GCMRC recognized the need for a more 

Program within the Grand Canyon. Experimentacarried out with little power to detect long-term techanges in the overall fish community. 

• In 2000, Carl Walters was hired to help develop a 

monitoring program that would better describe the within the Grand Canyon and with power to deteccommunity.

• Initial analyses of GCMRC fish data suggested th

(EL) may be most effective in monitoring rainbow and common carp and that netting (hoop and trameffectively capture trends in native fish. 

• Arizona Game and Fish Department took over the 

developing EL monitoring and SWCA was hired tsurveys.
Data driven approach to Lo

monitoring design 

(how many samples and w

• Carl W. Designed a visual basic program 

(SAMPLE.exe) to best focus our samplinterms of sample size and spatial allocatiothe species of concern. This program wadata from 1991-1999.

• In 2004 we recreated sample.exe in exce

reanalyzed data from 2000-2004 to refine monitoring.
reach samples

Samples per 

night

Samples 

boat 

1 48 24 2 48 24 3 120 24 4 48 24 5 168 24 6 96 24 7 96 24 8 48 24 9 90 30 

10 60 30 11 40 20 

sum 862 

Actual sample design 2005Total effort and allocation of effort by reach are based 

Reach River miles

1 0- 29.12 29.2- 563 56.1 – 68.64 68.7 - 76.75 78.8 -108.56 108.6 -1297 130.5 - 166.68 166.7- 179.59 179.8 - 200

10 200.1 - 22011 220.1 - 225
Bootstrap 

data 1000 times over varying Ns

CV by sample size for CRP

0.060.070.080.09

0.1

0.110.120.130.14

400 500 600 700 800

sample size

CV

Reality checkAdjust for logistic feasibility

% Five-year linear detectable 

change by sample size for CRP

0.00%5.00%

10.00%15.00%20.00%25.00%30.00%35.00%40.00%

400 500 600 700 800

sample size

Percent change Positive

Negative

How did we develop the current sampling stra
Rainbow trout

Mean CPUE (fish/hour) for rainbow trout at inin the Colorado River from Lees Ferry to Diamterm monitoring trips [2001-2005]). Each poin8-15) 

0.00

50.00

100.00150.00200.00250.00

0.00 50.00 100.00 150.00 

fish / hour

River Mile
Brown trout

Mean CPUE (fish/hour) for brown trout at indin the Colorado River from Lees Ferry to Diamterm monitoring trips [2001-2004]). Each poin8-15) 

0.00

20.0040.0060.0080.00

100.00120.00

0.00 50.00 100.00 150.00 

fish / hour

River Mile
Common carp

Mean CPUE (fish/hour) for common carp at insites in the Colorado River from Lees Ferry to (long-term monitoring trips [2001-2004]). Eacan N of 8-15) 

0.005.00

10.0015.0020.0025.0030.0035.0040.00

0.00 50.00 100.00 150.00 

River mile

fish / hour
Rainbow trout

Mean CPUE (fish/hour) in Grand C

(RM 0 – 226, 2000-2006)

YEAR

2000 2001 2002 2003 2004 2

RBT/Hour (95% CI)

605040302010

0
Brown trout

Mean CPUE (fish/hour) in Grand C

YEAR

2000 2001 2002 2003 2004 2

BNT/Hour (95% CI)

16141210

86420

-2

(RM 0 – 226, 2000-2006)
Carp

Mean CPUE (fish/hour) in Grand Cany

YEAR

2000 2001 2002 2003 2004 2005 

CRP/Hour (95% CI)

76543210

(RM 0 – 226, 2000-2006)
Flannelmouth sucker

Mean CPUE (fish/hour) in Grand Cany

YEAR

2000 2001 2002 2003 2004 200

FMS/Hour (95% CI)

141210

86420

-2

(RM 0 – 226, 2000-2006)
0%

10%20%30%

P

e

r

c

e

n

t

2000 2001 

2003 2004 

2006

0%

10%20%30%

P

e

r

c

e

n

t

0.00 200.00 400.00 600.00

TL

0%

10%20%30%

P

e

r

c

e

n

t

0.00 200.00 400.00 600.00

TL

0

Length histogramsBy year and percentof total catch

Flannelmouth su
12

569 10 

-4.00

0.004.008.00

12.00

FMS h/ our

D D D D D D D D D

D

D 

-4.00

0.004.008.00

12.00

FMS h/ our

D

D D D

D D D D

D D D 

2000 2001 2002 2003 2004

year

-4.00

0.004.008.00

12.00

FMS h/ our

D D

D

D

D

2000 2001 2002 2003 2004

year

D D D

D

2000 200

D

Mean CPUE (fish/hour) for flannelmouth sucker (by year) in Logistic reaches. (2000-2004)

Flannelmouth su
Grand Canyon Colorado River Temperatures (°C) 

August 1988 to July 2005

-15

0

153045607590

105120135150165180195210225

Miles from Lees Ferry

Lees Ferry

Abv LCR Blo LCR

Papago

Phantom

Dubendorf

MatKat

National

Parashant

Diamond Gage

YEAR

94 95 96 97 98 99 00 01 0

20 °C

19 °C

18 °C

17 °C

68.0°F

66.2°F

64.4°F

62.6°F

Glen Cyn Dam
Bluehead sucker

Mean CPUE (fish/hour) in Grand Cany

YEAR

2000 2001 2002 2003 2004 2005 

BHS/Hour (95% CI)

3.02.52.01.51.0

.5

0.0

-.

5

(RM 0 – 226, 2000-2006)
Diamond down (RM 22

June-July 2005

FMS HBC SPD BHS CCF CRP FHM MOS 

Electrofishing 56 0 32 0 8 30 6 0 Angling 0000 80 5 0 0 

Trammel netting 4000 24 30 0 0 

Hoop netting 9 1 10 0 1410Longlines 0000 9000Seining 29 3 5 0 0 0 2 0 Backpack electrofishing 8 0 49 0 4 13 0 8 TOTAL 106 4 96 0 126 82 9 8 

BHS = bluehead sucker, CCF = channel catfish, CRP = common carp, FHM = flannelmouth sucker, HBC = humpback chub, MOS = mosquitofish, RBT = rai

SMB = smallmouth bass, SPD = speckled dace, STB = striped bass, and TFS 
RBT (fish / hour) within an

the LCR depletion a

YEAR

2000 2001 2002 2003 2004 2005 2006

RBT / hour (95% CI)

100

80604020

0
Examples of output from early attempts at abundance an

This is only an example of the potential. Trends are real, numbers are e

guesses and place holders) and are pending further analysis an

0%

10%20%30%40%50%60%70%80%90%

100%

Percent total abundance

2000 2001 2002 2003 2004 2005 2006

Year

Percent Total abundance by year 

BHS FMS CRP BNT RBT 

0%

20%40%60%80%

100%

Percent total mass (kg)

2000 2001 2002 2003 

Yea

Percent total 

RBT abundance by reach

-50000

0

50000

100000150000200000

0 2 4 6 810 12

Fish Reach

Abundance

2000200120022003200420052006

FMS Dens

-500

0

500

10001500200025003000

0 2 4 

Density (fish / mile)

2000200120022003200420052006
Conclusions I

• The current electroshocking monito

appears to be appropriate for RBT, and BHS.

• We need to reevaluate results from 

monitoring.

• Salmonid densities have experienc

decline over the most recent years and BHS have increased significan

• Recent higher water temperatures 

partially responsible for both the desalmonids and increase in suckers.
Conclusions II

• Gear comparisons show that electroshoc

appropriate for detection of most non-natspecies likely to occur in Grand Canyon. 

• Long-term monitoring offers a larger data 

control for more temporally or spatially diexperiments.

• Catch per unit effort data may be convert

abundance and biomass in future modeliThis will allow us the ability to incorporate data into larger models such as carbon becopath models.
Robust long-term monitoring of aquatic pop

important to adaptive management program

characterizes a “baseline” or antecedent conte

response of biota to changing management 

experiments can be interpreted.

(Walters and Holling 1990; Thomas 1996; W

Thank You