U.S. Department of the Interior

U.S. Geological Survey

Josh Korman, Ecometrics, Inc. Vancouver, B.C.

Michael D. Yard, GCMRC, Flagstaff, AZ.

Natal Origins: Glen Canyon and Marble Canyon
Spatially referenced sampling

o Site length (250 m)

o Total of 1,160 sites

o Estimate movement probabilities

Annual fall marking trips (Oct- Dec)

o Age-0 (FL >75 mm)

o ~ 10,000 marked animals

o Glen Canyon Dam to Lees Ferry

 Quarterly trips for tag recovery 

and mark-recapture 

o Jan, Apr, Jul, and Sep

5 Study Reaches

o LEES FERRY (-5.5 to -2.1 RM)

o HOUSE ROCK (17.2-20.6 RM)

o BUCK FARM (38.2 to 41.6 RM)

o ABOVE LCR (60.2 to 61.2 RM)

o BELOW LCR (63.4 to 64.4 RM)

Sampling Design
Sampling Design

 Mark-Recapture

o Robust Design 

o 2 – Electrofishing boats (Osprey)

o Conduct 2-pass mark recapture

48 sampling sites / sampling 

reach

o Sample 32 sites / night

o Exception Reaches 4A & 4B (LCR)

Rapid Computer Data-entry 

Program

n = 16

n = 16

n = 16

n = 16

HOUSE ROCK (17.2-20.6 RM)
2011 2011

Common Name Nov Apr Jul Sep Oct Dec Nov Apr Jul Sep Oct Dec

Yellow Bullhead 3 - 3 2 1 - -

Bluehead Sucker 11 23 13 - 42 120 95 - -

Brown Trout 29 12 14 10 11 18 - 2 2 3 - -

Channel Catfish 1 - 2 1 1 - -

Common Carp 2 5 3 2 8 - 5 9 3 - -

Fathead Minnow 41 8 36 - 509 303 627 - -

Flannelmouth Sucker 83 190 115 4 - 58 81 89 - -

Green Sunfish 1 1 1

Humpback Chub 88 60 114 - 1,267 875 3,600 - -

Killifish 1 - 9 62 29 - -

Rainbow Trout 16,559 11,889 11,642 17,884 22,950 12,733 - 118 215 272 - -

Red Shiner 2 1 5 - 39 24 65 - -

Smallmouth Bass 1 1

Speckled Dace 10 2 2 - 85 16 42 - -

Unknown 2 - - 2 - - -

Total Catch 16,588 12,138 11,949 18,186 22,964 12,766 - 2,139 1,712 4,827 - -

Juvenile Chub Monitoring

2012 2012

Natal Origin

CATCH TABLE
PIT-tag 

Releases and Recaptures

Nov., 2011 (12,320 80-150 mm age-0 LF only)

Apr., 2012 (2,164 >=80 mm, all reaches)

Jul., 2012 (2,947 >=80 mm, all reaches)

Sep., 2012 (2,789 >=80 mm, all reaches)

Oct. & Dec. 2012 (9,432 75-150 mm age-0 LF only)

 1,173 across-trip recaptures based on 26,863 releases between 

Nov. 2011 and Dec. 2012.
Rainbow Trout Early Larval Life-history

Study (RTELSS)

Low High Total

July Nov. July Nov. July Nov.

2008 392 9 493 66 883 75

2009 171 15 179 46 350 62

2010 70 3 69 57 140 61

2011 451 88 234 123 686 214

2012 252 51 124 48 377 100

0

200

400

600

800

1000

1200

4 5 6 7 8 9 1112 6 7 8 9 11 6 7 8 9 11 5 6 7 8 9 101112 5 6 7 8 9 11 7 8 9 11 7 8 9 11 7 8 9 11

2004 2006 2007 2008 2009 2010 2011 2012

Low Angle

High Angle

Age-0 Abundance (‘000’s)

Abundance
U.S. Department of the Interior

U.S. Geological Survey

100

150

200

250

300

350

Abundance ('000s)

RTELSS-Nov. 11DI-Nov. 11DD-Nov. 11RTELSS-Nov. 12DI-Oct. 12DD-Oct. 12DI-Oct. 12 (Myr)DD-Oct. 12 (Myr)

Rainbow Trout Age-0 Estimates 

2011 2012
October 2012

December 2012

PIT-tagged = 5,156

PIT-tagged = 4,276

Glen Canyon Dam to Lees Ferry

(Rainbow Trout Electrofishing Catch Densities)

# RBT (<150 mm FL)/250 m

Catch Densities for Age-0 = 11,947

Catch Densities for Age-0 = 6,961
0

1,000

2,000

3,000

4,000

5,000

6,000

7,000

8,000

9,000

10,000

11,000

12,000

LEES

FERRY

HOUSE

ROCK

BUCK

FARM

ABOVE

LCR

BELOW

LCR

Abundance (# fish / km)

APRIL

LEES

FERRY

HOUSE

ROCK

BUCK

FARM

ABOVE

LCR

BELOW

LCR

JULY

LEES

FERRY

HOUSE

ROCK

BUCK

FARM

ABOVE

LCR

BELOW

LCR

SEPTEMBER

Rainbow Trout Abundance - 2012
Lees Ferry 

(-6 to -2 RM)

House Rock 

(17 to 20 RM)

Buck-farm 

(38 to 41 RM)

Above LCR 

(60 to 61 RM) Below LCR 

(63 to 64 RM)

Glen Canyon ~ 158,000

Marble Canyon ~ 373,000

Glen Canyon

Marble Canyon
-1.00

-0.80

-0.60

-0.40

-0.20

0.00

0.20

0.40

0.60

0.80

1.00

LEES FERRY

HOUSE ROCK

BUCK FARM

UP_LCR

DWN_LCR

DAILY GROWTH RATE (mm/da)

PIT-Tag Recaptures (Δ April - July)

-1.00

-0.80

-0.60

-0.40

-0.20

0.00

0.20

0.40

0.60

0.80

1.00

LEES FERRY

HOUSE ROCK

BUCK FARM

UP_LCR

DWN_LCR

DAILY GROWTH RATE (mm/da)

PIT-Tag Recaptures (Δ July - September)

Rainbow Trout (≥ 150 mm FL)

n= 17 n= 32 n= 75 n= 70 n= 26 n= 22 n= 83 n= 155 n= 60 n= 28

APRIL to JULY (~76 da) JULY to SEPTEMBER (~70 da)
-1.00

-0.80

-0.60

-0.40

-0.20

0.00

0.20

0.40

0.60

0.80

1.00

LEES FERRY

HOUSE ROCK

BUCK FARM

UP_LCR

DWN_LCR

DAILY GROWTH RATE (g/da)

PIT-Tag Recaptures (Δ April - July)

-1.00

-0.80

-0.60

-0.40

-0.20

0.00

0.20

0.40

0.60

0.80

1.00

LEES FERRY

HOUSE ROCK

BUCK FARM

UP_LCR

DWN_LCR

DAILY GROWTH RATE (g/da)

PIT-Tag Recaptures (Δ July - September)

APRIL to JULY (~76 da) JULY to SEPTEMBER (~70 da)

Rainbow Trout (≥ 150 mm FL)

n= 10 n= 1 n= 6 n= 17 n= 6 n= 10 n= 85 n= 139 n= 60 n= 12
0

100

200

300

400

500

600

700

800

900

1000

0 100 200 300 400 500

Wet Weight (g)

Fork Length

LEES FERRY

HOUSE ROCK

BUCK FARM

ABOVE LCR

BELOW LCR

loge (Weight) = loge (a) + b loge (Length)

 -

 0.01

 0.02

 0.03

 0.04

 0.05

 0.06

 0.07

 0.08

 0.09

 0.10

80-84

105-109130-134155-159180-184205-209230-234255-259280-284305-309330-334355-359380-384405-409430-434455-459480-484

RELATIVE FREQUENCY

SIZE CLASS (Fork-length, mm)

LEES FERRY 

SEPTEMBER
 -

 10

 20

 30

 40

 50

 60

 70

80-84

105-109130-134155-159180-184205-209230-234255-259280-284305-309330-334355-359380-384405-409430-434455-459480-484

BIOMASS (Kg/Km)

SIZE CLASS (Fork-length, mm)

BUCKFARM

JULY

 -

 10

 20

 30

 40

 50

 60

 70

80-84

105-109130-134155-159180-184205-209230-234255-259280-284305-309330-334355-359380-384405-409430-434455-459480-484

BIOMASS (Kg/Km)

SIZE CLASS (Fork-length, mm)

ABOVE LCR

JULY

 -

 10

 20

 30

 40

 50

 60

 70

80-84

105-109130-134155-159180-184205-209230-234255-259280-284305-309330-334355-359380-384405-409430-434455-459480-484

BIOMASS (Kg/Km)

SIZE CLASS (Fork-length, mm)

HOUSE ROCK

JULY

 -

 10

 20

 30

 40

 50

 60

 70

80-84

105-109130-134155-159180-184205-209230-234255-259280-284305-309330-334355-359380-384405-409430-434455-459480-484

BIOMASS (Kg/Km)

SIZE CLASS (Fork-length, mm)

LEES FERRY

JULY
 -

 10

 20

 30

 40

 50

 60

 70

80-84

105-109130-134155-159180-184205-209230-234255-259280-284

305-309330-334355-359

380-384405-409430-434455-459480-484

BIOMASS (Kg/Km)

SIZE CLASS (Fork-length, mm)

LEES FERRY 

JULY

SEPTEMBER

 -

 10

 20

 30

 40

 50

 60

 70

80-84

105-109130-134155-159180-184205-209230-234255-259280-284305-309330-334355-359380-384405-409430-434455-459480-484

BIOMASS (Kg/Km)

SIZE CLASS (Fork-length, mm)

HOUSE ROCK

JULY

SEPTEMBER

 -

 10

 20

 30

 40

 50

 60

 70

80-84

105-109130-134155-159180-184205-209230-234255-259280-284305-309330-334355-359380-384405-409430-434455-459480-484

BIOMASS (Kg/Km)

SIZE CLASS (Fork-length, mm)

BUCKFARM

JULY

SEPTEMBER

 -

 10

 20

 30

 40

 50

 60

 70

80-84

105-109130-134155-159180-184205-209230-234255-259280-284305-309330-334355-359380-384405-409430-434455-459480-484

BIOMASS (Kg/Km)

SIZE CLASS (Fork-length, mm)

ABOVE LCR

JULY

SEPTEMBER

Age-1

Age-2+
 -

 200

 400

 600

 800

 1,000

 1,200

LEES FERRYHOUSE ROCKBUCK FARMUP_LCRDWN_LCR

WET WEIGHT (kg/km)

JULY 2012

 -

 200

 400

 600

 800

 1,000

 1,200

LEES FERRYHOUSE ROCKBUCK FARMUP_LCRDWN_LCR

WET WEIGHT (kg/km)

SEPTEMBER 2012
0%

5%

10%

15%

20%

25%

30%

35%

40%

0.0-0.10.2-0.30.4-0.50.6-0.70.8-0.91.0-1.11.2-1.31.4-1.51.6-1.71.8-1.92.0-2.12.2-2.32.4-2.5

>3

Percentage 

Kilometers Upstream (km)

≥ Age-1 RBT

0%

5%

10%

15%

20%

25%

30%

35%

0.0-0.51.0-1.52.0-2.53.0-3.54.0-4.55.0-5.56.0-6.57.0-7.58.0-8.59.0-9.5

>10.0

Percent age

Kilometers Downstream (km)

≥ Age-1 RBT

2012 PIT-Tag Recaptures

UPSTREAM DOWNSTREAM
Long-Range Movement to Date

PIT ID Release Recapture Release Recapture Release Recapture Growth (mm) Miles Kilometers

384.1B796B6F61 Nov. 11 Apr. 12 -4.9 18.7 90 125 35 23.6 38.0

384.1B796BB627 Nov. 11 Apr. 12 -11.6 19.1 93 107 14 30.7 49.4

384.1B796CA340 Apr. 12 Jul. 12 -6.2 17.4 299 312 13 23.6 38.0

384.1B796BA11E1 Apr. 12 Jul. 12 60.3 64.1 305 316 11 3.8 6.1

384.1B796C994B Apr. 12 Sep. 12 -12.44 19.14 - - - 31.6 50.8

384.1B796CA80E1 Apr. 12 Sep. 12 60.47 64.45 205 243 38 4.0 6.4

384.1B796FAB90 Apr. 12 Sep. 12 19.28 61.01 294 297 3 41.7 67.1

384.1B796A4A351 Apr. 12 Sep. 12 60.2 64.56 254 268 14 4.4 7.0

384.1B796C9E18 Nov. 11 Jul. 12 -13.27 -0.84 91 113 22 12.43 7.0

384.1B796FA285 Nov. 11 Apr. 12 -3.2 -14.89 93 103 22 -11.69 7.0

Trip Location (mi) Fork Length (mm) Net Movement

1 Trout movement into study reach located below the LCR confluence 
 -

 0.01

 0.02

 0.03

 0.04

 0.05

 0.06

 0.07

 0.08

 0.09

 0.10

80-84

105-109130-134155-159180-184205-209230-234255-259280-284305-309330-334355-359380-384405-409430-434455-459480-484

RELATIVE FREQUENCY

SIZE CLASS (Fork-length, mm)

LEES FERRY 

JULY

SEPTEMBER

 -

 0.01

 0.02

 0.03

 0.04

 0.05

 0.06

 0.07

 0.08

 0.09

 0.10

80-84

105-109130-134155-159180-184205-209230-234255-259280-284305-309330-334355-359380-384405-409430-434455-459480-484

RELATIVE FREQUENCY

SIZE CLASS (Fork-length, mm)

HOUSE ROCK

JULY

(Increased Growth)

(Reduced Abundance)

 -

 0.01

 0.02

 0.03

 0.04

 0.05

 0.06

 0.07

 0.08

 0.09

 0.10

80-84

105-109130-134155-159180-184205-209230-234255-259280-284305-309330-334355-359380-384405-409430-434455-459480-484

RELATIVE FREQUENCY

SIZE CLASS (Fork-length, mm)

LEES FERRY 

(Age-1, 2011) JULY

(Age-1, 2011)

 -

 0.01

 0.02

 0.03

 0.04

 0.05

 0.06

 0.07

 0.08

 0.09

 0.10

80-84

105-109130-134155-159180-184205-209230-234255-259280-284305-309330-334355-359380-384405-409430-434455-459480-484

RELATIVE FREQUENCY

SIZE CLASS (Fork-length, mm)

HOUSE ROCK

JULY

SEPTEMBER
CONCLUSION

o Uncertain whether or not the Fall-2012 HFE had any direct effect on the apparent survival 

or abundance levels of Age-0 RBT in Glen Canyon.

• Abundance estimates for December (Post-HFE) are to be performed and reported on in the next 

couple of months (Feb.-Mar.)

• Owing to differences in capture probabilities across trips, differences in observed catch densities 

will not always correspond to changes in actual abundance.

o To date, no significantl large scale change in trout abundances (2-pass method) has 

occurred in any of the downstream reaches. 

• 70% of all rainbow are currently found downstream in Marble Canyon.

• Trout abundance is unevenly distributed from Glen Canyon to Little Colorado River.

• Upstream removal activities (PBR) are not likely to be very effective at reducing trout densities at the 

LCR confluence area.

 Growth was geographically and seasonally variable in the Colorado River.

 Factors like density dependence (Lees Ferry) and turbidity (Marble Canyon) are likely influencing 

rainbow trout growth.

 Daily growth rate measured as weight rather than length appears to be a more sensitive metric for 

evaluating growth. 

 Minimal downstream movement of rainbow trout was observed in 2012.

 Only 33% of al recaptured fish show any downstream movement

 Most large scale movement (> 10 km) occurs in a downward direction.

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

0.40

0.45

0.50

Δ Nov 2011 to Apr 2012

Δ April to July 2012

Δ July to Sep 2012

Δ Oct to Dec 2012

DAILY GROWTH RATE (mm/da)

LEES FERRY

< 150 mm FL

≥150 mm FL

(~160 da)

(~76 da)

(~70 da)

(~45 da)

n= 72 n= 4 n= 10 n= 262
-2.50

-2.00

-1.50

-1.00

-0.50

0.00

0.50

1.00

1.50

2.00

2.50

LEES FERRY HOUSE ROCK BUCK FARM UP_LCR DWN_LCR

DAILY GROWTH RATE (g/da)

Rainbow Trout

PIT-Tag Recaptures (Δ July - September)
-2.50

-2.00

-1.50

-1.00

-0.50

0.00

0.50

1.00

1.50

2.00

2.50

LEES FERRY HOUSE ROCK BUCK FARM UP_LCR DWN_LCR

DAILY GROWTH RATE (g/da)

Rainbow Trout

Population method (no adjustment)

PIT-Tag Recaptures (Δ July - September)
-2.50

-2.00

-1.50

-1.00

-0.50

0.00

0.50

1.00

1.50

2.00

2.50

LEES FERRY HOUSE ROCK BUCK FARM UP_LCR DWN_LCR

DAILY GROWTH RATE (g/da)

Rainbow Trout

PIT-Tag Recaptures (Δ July - September)

Population method (adjusted for immigration and emigration)
Atypical Flow Events

b

Date

3/5/08 3/7/08 3/9/08 

0

10000

20000

30000

40000

50000

d

Date

11/19/12 11/21/12 11/23/12 

Colorado River Flows (cubic feet per second) at Lees Ferry, Arizona

0

10000

20000

30000

40000

50000

a

Date

Jan Jul Jan Jul Jan Jul Jan Jul Jan Jul Jan 

Colorado River Flows (cubic feet per second) at Lees Ferry, Arizona

0

10000

20000

30000

40000

50000

c

Date

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan 

8000

10000

12000

14000

16000

18000

20000

22000

24000

26000

28000

2008 2009 2010 2011

2011

2012
Results

Larval/Juvenile Monitoring

July

20 40 60 80 100 120 140 160

Count

0

100

200

300

August

20 40 60 80 100 120 140 160

0

100

200

300

September

Fork Length (mm)

20 40 60 80 100 120 140 160

Count

0

100

200

300

November

Fork Length (mm)

20 40 60 80 100 120 140 160

0

100

200

300

Low Angle

High Angle

Low Angle=1666

High Angle=1174

Low Angle=1416

High Angle=1582

Low Angle=788

High Angle=1102

Low Angle=349

High Angle=325

2012
Results

Spawning

Nov Dec Jan Feb Mar Apr May Jun Jul

Total 

Surveys

Redds 

Count

Estimated #

of Redds

2003 1 1 1 1 1 1 6 2661 2310

2004 1 1 1 2 2 1 2 1 11 3596 2310

2006 1 1 2 2 2 2 1 11 165 90

2007 1 1 1 1 1 1 1 7 1186 1215

2008 1 2 2 2 1 1 1 10 2741 1875

2009 1 1 1 2 2 2 2 11 3107 1697

2010 1 1 1 1 1 5 895 900

2011 1 2 1 2 2 1 9 4433 3062

2012 1 1 2 2 1 1 8 2286 1852

Mean 1701.2

SE 291.6