U.S. Department of the Interior

U.S. Geological Survey

Josh Korman, Ecometric Research, Vancouver, BC

Michael D. Yard, USGS GCMRC, Flagstaff, AZ

Natal Origins of Rainbow Trout:

Glen Canyon and Marble Canyon

Glen Canyon Dam Adaptive Management Program

Annual Reporting Meeting

January 28, 2014
Conceptual Model

Lees Ferry Marble Canyon

LCR

LCR Inflow Reach

Paria

Recruitment

Survival

Growth

Emigration rate

Immigration/Emigration

Survival

Growth

Immigration/Emigration, Survival,

Growth, Local Recruitment

Returning Spawners?

Local Recruitment
Natal Origin - Study Objectives

1. Quantify extent of rainbow trout movement from Lees Ferry into Marble 

Canyon and LCR inflow

2. Determine factors that drive trout movement (density, food, growth, turbidity, 

HFEs, etc.)

3. Quantify extent of local reproduction below Lees Ferry.

4. Estimate abundance of rainbow trout in LCR inflow reach for FWS 

Biological Opinion and ‘Trigger’

5. Continue monitoring juvenile humpback chub abundance, growth, and 

survival in the LCR inflow reach (BioOp/trigger)

6. Relate chub survival and growth to trout abundance and temperature 

(critical uncertainty)
Overview of Presentation

Design of sampling and mark-recapture study

RBT Abundance, capture probability, and survival

RBT Movement, tag recaptures, population trends, 

length- and age-frequency trends

RBT Growth

RBT Local reproduction

Conclusions
Annual age-0 marking trips 

from dam to Lees Ferry

o Length >75 mm

o ~ 10,000 marked/yr

o Nov. 2011, Oct & Dec 2012, 2013

 Quarterly trips for marking and 

tag recovery by Reach

o Apr, Jul, Sep, Jan

o LEES FERRY (I, -5.5 to -2.1 RM)

o HOUSE ROCK (II, 17.2-20.6 RM)

o BUCK FARM (III, 38.2 to 41.6 RM)

o ABOVE LCR (IVa, 60.2 to 61.2 RM)

o BELOW LCR (IVb, 63.4 to 64.9 RM)

Sampling Design
Sampling Design

Reaches I - IVa

o 2 nights of effort per reach

o 32 250 m sites are sampled per night (4 km)

o 16 sites (2 km) are sampled on nights 1 and 2 

(robust design section).

o Marks released in robust design section

o IVa consists only of robust design section

Reach IVb (below LCR)

o 2.4 km long (heart isl. – carbon ck.)

o Robust design section only

o 5 passes of effort which includes fast (2) and 

slow (3) passes of electrofishing, and 8 

passes of hoop netting

n = 16

n = 16

n = 16

HOUSE ROCK (17.2-20.6 RM)
Summary of RBT Catch and PIT 

Releases

Total RBT

Name: Catch Lees Ferry Lees Ferry House Rock Buck Farm U/S LCR D/S LCR

Reach #: All Reaches All I II III IVa IVb

RM: (-15.6 - 64.9) (-15.6 - 0) (-5.5 - -2.1) (17.2 - 20.6) (38.2 - 41.5) (60.2 - 61.1) (63.4 - 64.9)

Nov-11 16,559 11,485

Apr-12 12,006 609 552 549 317 119

Jul-12 11,855 768 795 848 339 197

Sep-12 18,155 625 788 842 305 229

Oct-12 22,950 5,088

Dec-12 12,733 4,254

Jan-13 12,338 728 776 987 347 336

Apr-13 9,992 870 1,010 879 367 135

Jul-13 8,625 815 828 882 428 279

Sep-13 14,041 1,122 1,068 741 478 351

Oct-13 13,283 5,838

Dec-13 8,846 5,536

Jan-14 9,192 949 1209 1198 555 388

Total 170,575 32,201 6,486 7,026 6,926 3,136 2,034 57,809

PIT Tag Releases

Preliminary Data, Do Not Cite
Summary of PIT Recaptures

Name: Lees Ferry Lees Ferry House Rock Buck Farm U/S LCR D/S LCR

Reach #: All I II III IVa IVb

RM: (-15.6 - 0) (-5.5 - -2.1) (17.2 - 20.6) (38.2 - 41.5) (60.2 - 61.1) (63.4 - 64.9)

Nov-11 250 253 0 0 0 0

Apr-12 80 133 201 146 42

Jul-12 101 201 296 128 60

Sep-12 65 160 198 118 58

Oct-12 341 342 0 0 0 0

Dec-12 163 164 0 0 0 0

Jan-13 98 166 179 120 62

Apr-13 85 188 199 118 39

Jul-13 99 134 179 110 49

Sep-13 54 62 86 64 32

Oct-13 362 385 0 0 0 0

Dec-13 58 0 0 0 0

Jan-14

Total 1,116 1,784 1,044 1,338 804 342 6,428

Preliminary Data, Do Not Cite
Abundance By Reach

Reach I (LF)

Apr12Jul12Sep12Jan13Apr13Jul13Sep13Jan14

10

15

20

Reach II (HR)

Apr12Jul12Sep12Jan13Apr13Jul13Sep13Jan14

4

6

8

10

12

Reach III (BF)

Apr12

Jul12Sep12Jan13Apr13Jul13Sep13Jan14

2.5

3.0

3.5

4.0

4.5

Reach IVa (US LCR

Apr12Jul12Sep12Jan13Apr13Jul13Sep13Jan14

0.4

0.6

0.8

1.0

1.2

1.4

Reach IVb (DS LCR

Apr12Jul12Sep12Jan13Apr13Jul13Sep13Jan14

0.2

0.3

0.4

0.5

0.6

Trip

Abundance ('000s per km)

Preliminary 

Data, Do 

Not Cite
System-Wide Abundance

Apr12 Jul12 Sep12 Jan13 Apr13 Jul13 Sep13 Jan14

GCD-LF

LF-HR

HR-BF

BF-LCR

LCR-Carbon

Trip

Abundance (millions)

0.0

0.2

0.4

0.6

0.8

1.0

1.2

Preliminary 

Data, Do 

Not Cite
0 5 10 15

0.05

0.10

0.15

0.20

0.25

0.30

Within Trips

Capture Probability

I

II

III

IVa

IVb

0 5 10 15

0.05

0.10

0.15

0.20

0.25

0.30

Across Trips

Abundance ('000s per km)

Capture Probability

Sep 13 Sep 12

Preliminary 

Data, Do 

Not Cite
90 Day Surviv 

I II III IVa IVb

0.5

0.6

0.7

0.8

0.9

Reach

Turnover Rate

I II III IVa IVb

0.1

0.2

0.3

0.4

0.5

0.6

Survival and Turnover

Preliminary 

Data, Do 

Not Cite
Tag-Based Movement

All Recaptures (n=4495)

Distance between release and reca 

-10 -5 0 5 10

Lower 2.5% = -2.4 km

Upper 97.5% = 3.6 km

Preliminary 

Data, Do 

Not Cite
Movement: 2012-2013 vs. 2003-2006

Natal Origins (n= 2044)

-10 -5 0 5 10

Lower 2.5% = -1.7 km

Upper 97.5% = 3.9 km

Mechanical Removal (n= 1564)

Distance between release and recapture loc 

-10 -5 0 5 10

Lower 2.5% = -6.4 km

Upper 97.5% = 21.6 km

Preliminary 

Data, Do 

Not Cite
Large Movements (> 20 km or <-20 km)

KM From LF From MC

TAG Release Recapture Release Recapture Moved Release Recapture to MC to LF

384.36F2B29B09 Sep2012 Jul2013 63.73 -5.05 -110.7 269 299 1

384.36F2B295C9 Sep2012 Dec2013 40.34 -0.16 -65.2 241 282 1

384.36F2B29CF7 Sep2012 Oct2013 19.4 -12.0 -50.6 360 365 1

384.1B796FB0AA Jul2012 Dec2013 19.27 -10.8 -48.4 340 341 1

384.36F2B2979B Sep2012 Dec2013 18.4 -11.2 -47.6 178 199 1

384.36F2B2A465 Sep2012 Oct2013 18.8 -9.7 -45.9 204 275 1

384.36F2B28F27 Jan2013 Oct2013 18.7 -8.3 -43.4 205 238 1

384.1B796B8E57 Jul2012 Jul2013 63.8 41.2 -36.4 250 271

384.36F2B2970E Sep2012 Sep2013 18.9 -2.5 -34.3 237 296 1

384.36F2B2BAC5 Jan2013 Oct2013 19.3 -2.0 -34.2 227 259 1

384.36F2B2A9E9 Jan2013 Apr2013 39.46 18.54 -33.7 278 281

384.1B796F9F26 Apr2012 Sep2013 39.5 18.8 -33.2 158 271

384.36F2B2A4DE Sep2012 Sep2013 39.9 19.9 -32.3 254 274

384.36F2B2990E Sep2012 Jan2014 60.9 41.47 -31.3 273 311

384.36F2B29CF6 Apr2013 Jan2014 38.2 19.12 -30.7 236 249

384.1B796C9E18 Nov2011 Jul2012 -13.27 -0.798 20.1 91 113

384.1B796AA011 Nov2011 Jan2013 4.12 19.42 24.6 94 223

384.1B796B788B Nov2011 Jul2013 -2.0 17.4 31.1 97 254 1

3DD.003BA0A245 Sep2013 Jan2014 18.54 38.48 32.1 257 260

384.36F2B2A4D7 Sep2012 Jan2013 40.2 60.2 32.3 209 216

3DD.003B9C285D Jul2013 Sep2013 39.89 60.73 33.5 314 302

3DD.003BA03777 Jul2013 Jan2014 18.54 39.45 33.7 265 263

3DD.003BA05BA6 Apr2013 Jul2013 18.39 39.45 33.9 212 248

3DD.003BA03097 Jan2013 Jan2014 40.04 61.19 34 207 244

384.36F2B2939B Sep2012 Sep2013 39.46 61.19 35 205 253

384.1B796B6F61 Nov2011 Apr2012 -4.9 18.7 37.9 90 125 1

384.1B796BB5D5 Apr2012 Apr2013 40.04 64.13 38.8 140 214

384.36F2B253FB Jul2012 Jan2013 39.3 63.72 39.3 289 284

384.36F2B2B750 Jan2013 Apr2013 39.5 64.8 40.8 215 222

384.1B796BBD34 Nov2011 Sep2013 -11.91 18.54 49 142 259 1

384.1B796BB627 Nov2011 Apr2012 -11.55 19.12 49.4 93 107 1

384.1B796C994B Nov2011 Sep2012 -12.4 19.1 50.8 120 240 1

384.36F2B25213 Sep2012 Sep2013 18.82 60.34 66.8 204 272

3DD.003BA03F58 Jul2013 Jan2014 18.66 60.36 67.1 273 268

384.1B796FAB90 Jul2012 Sep2012 19 61.01 67.6 292 297

3DD.003B9C2F6C Jul2013 Jan2014 19.42 63.96 71.7 256 252

3DD.003BA028C5 Jan2013 Sep2013 18.54 64.1 73.3 115 270

384.36F2B28F69 Jan2013 Jan2014 18.24 65.12 75.4 250 273

Trip Location Fork Length (mm)

Preliminary 

Data, Do 

Not Cite
Within-Reach Movement (summary)

-2 -1 0 1 2

0.0

0.5

1.0

1.5

2.0

2.5

3.0

I

-2 -1 0 1 2

0.0

0.5

1.0

1.5

II

-2 -1 0 1 2

0.0

0.5

1.0

1.5

2.0

2.5

III

-2 -1 0 1 2

0.0

0.5

1.0

1.5

2.0

IVa

-2 -1 0 1 2

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

IVb

Apr12-Jul12

Jul12-Sep12

Sep12-Jan13

Jan13-Apr13

Apr13-Jul13

Jul13-Sep13

Sep13-Jan14

Distance between Release and Re 

Density

Preliminary 

Data, Do 

Not Cite
Overview of Presentation

Design of sampling and mark-recapture study

RBT Abundance, capture probability, and survival

RBT Growth

RBT Local reproduction

Conclusions

RBT Movement, tags, population trends, length- and 

age-frequency trends
Reach I (LF)

Apr12Jul12Sep12Jan13Apr13Jul13Sep13Jan14

10

15

20

Reach II (HR)

Apr12Jul12Sep12Jan13Apr13Jul13Sep13Jan14

4

6

8

10

12

Reach III (BF)

Apr12Jul12Sep12Jan13Apr13Jul13Sep13Jan14

2.5

3.0

3.5

4.0

4.5

Reach IVa (US LCR

Apr12Jul12Sep12Jan13Apr13Jul13Sep13Jan14

0.4

0.6

0.8

1.0

1.2

1.4

Reach IVb (DS LCR

Apr12Jul12Sep12Jan13Apr13Jul13Sep13Jan14

0.2

0.3

0.4

0.5

0.6

Trip

Abundance ('000s per km)

Evidence for Downstream Dispersal: 

Population Trends

Lees Ferry

House Rock

Buckfarm

Above LCR

Below LCR

FWS BO Criterion

Preliminary 

Data, Do 

Not Cite
Reach I. Sample Size 3233

0 100 200 300 400

Reach II. Sample Size 2055

0 100 200 300 400

Reach III. Sample Size 1937

0 100 200 300 400

Reach IVa. Sample Size 372

0 100 200 300 400

Reach IVb. Sample Size 145

0 100 200 300 400

April 2012

Fork Length (mm)

Evidence for Downstream Dispersal: 

Downstream Increase in Size of Smallest Fish

Large 2011 

cohort

Lees Ferry

Houserock

Buckfarm

Above LCR

Below LCR

Preliminary 

Data, Do 

Not Cite
Fitting RBT Growth in Length

100 200 300 400 500

-10

-5

0

5

10

15

20

25

Jul12-Sep12

100 200 300 400 500

-10

-5

0

5

10

15

20

25

Sep12-Jan13

100 200 300 400 500

-10

-5

0

5

10

15

20

25

Jan13-Apr13

ObsGrow

100 200 300 400 500

-10

-5

0

5

10

15

20

25

Apr13-Jul13

ObsGrow

Size-at-Release (mm)

Observed and Predicted Monthly Growth 

Buckfarm

5 mm/Mo

2.5 mm/Mo

4 mm/Mo

10 mm/Mo

Preliminary 

Data, Do 

Not Cite
0 100 200 300 400 500

-30

-20

-10

0

10

20

Jul12-Sep12

ObsG o

0 100 200 300 400 500

-15

-10

-5

0

Sep12-Jan13

ObsG o

0 100 200 300 400 500

-10

0

10

20

Jan13-Apr13

ObsG o

0 100 200 300 400 500

-20

-10

0

10

20

30

Apr13-Jul13

ObsG o

Size-at-Release (g)

Observed and Predicted Monthly Growth 

Fitting Growth in Weight

Buckfarm

-4.0 g/Mo

-5.0 g/Mo

10 g/Mo

16 g/Mo

Preliminary 

Data, Do 

Not Cite
Trends in Growth (@ 200 mm)

Apr12-Jul12

 

-10

0

10

20

30

Length Weight

Jul12-Sep12

 

-10

0

10

20

30

Sep12-Jan13

 

-10

0

10

20

30

I II III IVa IVb

Jan13-Apr13

 

-10

0

10

20

30

Apr13-Jul13

 

-10

0

10

20

30

Jul13-Sep13

 

-10

0

10

20

30

I II III IVa IVb

Reach

Monthly Growth (mm or g) for 200 mm Fi

Lees Ferry

Houserock

Buckfarm

Above LCR

Below LCR

Lees Ferry

Houserock

Buckfarm

Above LCR

Below LCR

Preliminary 

Data, Do 

Not Cite
Reach I

0.8

0.9

1.0

1.1

1.2

Reach II

0.8

0.9

1.0

1.1

1.2

Reach III

0.8

0.9

1.0

1.1

1.2

Apr2012Jul2012Sep2012Jan2013Apr2013Jul2013Sep2013

Reach IVa

0.8

0.9

1.0

1.1

1.2

Reach IVb

0.8

0.9

1.0

1.1

1.2

Apr2012Jul2012Sep2012Jan2013Apr2013Jul2013Sep2013

Relative Condition Factor

Trends in Condition Factor

Lees Ferry

Houserock

Buckfarm

Above LCR

Below LCR

Preliminary 

Data, Do 

Not Cite
Apr12 Jul12 Sep12 Jan13 Apr13 Jul13 Sep13 Jan14

GCD-LF

LF-HR

HR-BF

BF-LCR

LCR-Carbon

Biomass (metric tons)

0

50

100

150

200

Rainbow Trout Biomass

165 metric tons biomass

Preliminary 

Data, Do 

Not Cite
Lees Ferry

Houserock

Buckfarm

Above LCR

Below LCR

Invertebrate Drift Concentration

(Gammarus lacustris)

Preliminary 

Data, Do 

Not Cite
Length-at-Age: Convert length-frequencies 

to Age- and Birth Date-Frequencies

Age (yrs)

Fork length (mm)

100

150

200

250

300

350

1 2 3 4 5 6 7

1

2

3

4A

4B

Decrease in maximum RBT size late 70’s – 80’s

?

Lees Ferry

Houserock

Buckfarm

Above LCR

Below LCR

Preliminary 

Data, Do 

Not Cite
Evidence for Downstream Dispersal: Age-Frequencies 

Confirm Few Young Fish Downstream

I

1 2 3 4 5 6

II

1 2 3 4 5 6

III

1 2 3 4 5 6

IVa

1 2 3 4 5 6

IVb

1 2 3 4 5 6

Apr2012

Age (yrs)

Relative Frequency

Lees Ferry

Houserock

Buckfarm

Above LCR

Below LCR

Preliminary 

Data, Do 

Not Cite
Cohort Origins based on Birth Date 

Frequencies

I

2006 2008 2010 2012 2014

II

2006 2008 2010 2012 2014

III

2006 2008 2010 2012 2014

IVa

2006 2008 2010 2012 2014

IVb

2006 2008 2010 2012 2014

Apr2012

Birth Date

Relative Frequency

Lees Ferry

Houserock

Buckfarm

Above LCR

Below LCR

Preliminary 

Data, Do 

Not Cite
Jul12

0

20

40

60

80

100

120

100 200 300 400

Obs.

Pred.

0

50

100

150

200

100 200 300 400

0

50

100

150

100 200 300 400

Sep12

0

50

100

150

200

100 200 300 400

I

0

50

100

150

200

250

300

350

100 200 300 400

II

0

100

200

300

400

100 200 300 400

III

Fork length (mm)

Frequency

What Size/Age Group is Emigration from Lees Ferry?

Predicted vs. Observed Length Frequencies 

Where did 

these fish 

go?

Lees Ferry

Houserock

Buckfarm

Lees Ferry

Houserock

Buckfarm

?

?

Preliminary 

Data, Do 

Not Cite
Same Pattern in 2013

Jul13

0

20

40

60

80

100

100 200 300 400

0

50

100

150

200

250

100 200 300 400

0

50

100

150

100 200 300 400

Sep13

0

50

100

150

200

250

300

350

100 200 300 400

I

0

100

200

300

400

500

600

100 200 300 400

II

0

50

100

150

200

250

300

350

100 200 300 400

III

Fork length (mm)

Frequency

Lees Ferry

Houserock

Buckfarm

Lees Ferry

Houserock

Buckfarm

?

Preliminary 

Data, Do 

Not Cite
Reach I. Sample Size 1545

0 100 200 300 400

Reach II. Sample Size 1506

0 100 200 300 400

Reach III. Sample Size 1051

0 100 200 300 400

Reach IVa. Sample Size 423

0 100 200 300 400

Reach IVb. Sample Size 358

0 100 200 300 400

July 2013

Fork Length (mm)

2012

recruits

2012 

recruits

Not All Trout in Marble Canyon Originate from 

Lees Ferry: Evidence for Local Recruitment

2013

2012

2013

2011

2012

2013

Reach I. Sample Size 2802

0 100 200 300 400

Reach II. Sample Size 1942

0 100 200 300 400

Reach III. Sample Size 1346

0 100 200 300 400

Reach IVa. Sample Size 316

0 100 200 300 400

Reach IVb. Sample Size 220

0 100 200 300 400

July 2012

Fork Length (mm)

Lees Ferry

Houserock

Buckfarm

Above LCR

Below LCR

Lees Ferry

Houserock

Buckfarm

Above LCR

Below LCR

?

Preliminary Data, Do Not Cite
RBT Effects on Juvenile HBC 

Mainstem Survival

Preliminary 

Data, Do 

Not Cite
Conclusions

1. RBT Demographics

a) High trout abundance, 

b) Uneven spatial distribution, 

c) Good growth rates 

d) Moderately good survival upstream of the LCR. 

2. Capture probabilities are influenced by trout density and turbidity. 

a) Limits reliability of just using index sampling (CPUE) as the sole metric.

3. Limited downstream movement of tagged fish. 

4. Other findings suggest that MC/LCR inflow are immigrants from Lees Ferry. 
Conclusions

5. Movement Paradox is potentially explained by :

a) Episodic dispersal from Lees Ferry - slow dispersal rates between reaches

b) We are spatially biased due to methodology (Results in a higher probability of 

recapturing fish displaying small and large movement, not intermediate)

6. Mechanisms regulating movement (density dependence, flows, food, or 

tributary events, etc.) are uncertain.

7. Given 1 - 6, Paria-Badger removal (PBR) is not seem feasible for regulating 

trout numbers.
Acknowledgements

 Administrative support: Scott VanderKooi, Ted Melis

 GCMRC logistics: Carol Fritzinger, Seth Felder, and Dave Foster

 Sampling design and modelling: Charles Yackulic and Carl Walters

 Humphrey Summit Support: Brian Dierker, Brett Stark, Jason Moore, Scott 

Perry, and others

 Many paid and volunteer technicians, especially: Jake Hall, Colton 

Finch, Mariah Giardini, Evan Anderson, Luke Avery, Margeaux Bestard, Chelsie 

Arndt, Ellie Johnson, Tanner Carothers, Ben Vaage