U.S. Department of the Interior

U.S. Geological Survey

2015 HFE Discussion:

Biological Resource Updates

Scott VanderKooi and Paul Grams

Southwest Biological Science Center

Grand Canyon Monitoring and Research Center
Photo: Randall Babb

Photo: George Andrejko

Rainbow Trout and Humpback Chub Updates
Glen Canyon/ 

Lees Ferry

Marble 

Canyon

Little Colorado River 

and Confluence
0

500

1000

1500

2000

2500

3000

3500

May/June 2001

April/May 2002April/May 2003April/May 2004April/May 2005April/May 2006April/May 2007April/May 2008April/May 2009

May/June 2010May/June 2011

April/May 2012April/May 2013April/May 2014April/May 2015

Abundance estimate

Spring LCR 150-199 mm Humpback 

Chub abundance estimates 2015 spring abundance 

estimate of 150-199 mm 

HBC = 921 

(95% CI: 756 to 1086). 

(Preliminary Data from VanHaverbeke et al. USFWS. 2015. Do Not Cite.)
0

1000

2000

3000

4000

5000

6000

7000

8000

May/June 01

April/May 02April/May 03April/May 04April/May 05April/May 06April/May 07April/May 08April/May 09

May/June 10May/June 11

April/May 12April/May 13

April/May 2014April/May 2015

Abundance estimate

Annual spring abundances of Humpback Chub 

≥ 200 mm in lower 13.6 km of LCR 2015 spring estimates 

considerably lower than 

recent years. Potentially 

due to early run timing, 

skipped spawning, or 

population decline.

(Preliminary Data from VanHaverbeke et al. USFWS. 2015. Do Not Cite.)
Number of Unique Fish Detected

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

Humpback 

Chub 

detections 

on Little 

Colorado 

River PITtag arrays

2015 run timing 

similar to 2014. 

Fewer detections 

could be due to 

skipped spawning or 

population decline.

(Preliminary data from Avery 

2015. Do Not Cite.)
Condition factor of Humpback Chub 

in JCM reach (downstream of LCR confluence)

Lower condition observed in 3 of last 

4 trips. Supports hypothesis of 

skipped spawning due to less energy 

available to devote to reproduction

(Preliminary data from Yackulic and Korman 2015. Do Not Cite.)

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, 

and 2014

 Quarterly trips for marking and 

tag recovery by reach

o Jan, Apr, Jul, and Sept

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)

Rainbow Trout Natal 

Origins Study 

Sampling Design
I

0

5

10

15

20

25

30

35

Apr2012Jul2012Sep2012Jan2013Apr2013Jul2013Sep2013Jan2014Apr2014Jul2014Sep2014Jan2015Apr2015

II

0

5

10

15

20

25

30

Apr2012Jul2012Sep2012Jan2013Apr2013Jul2013Sep2013Jan2014Apr2014Jul2014Sep2014Jan2015Apr2015

III

0

1

2

3

4

5

6

7

Apr2012Jul2012Sep2012Jan2013Apr2013Jul2013Sep2013Jan2014Apr2014Jul2014Sep2014Jan2015Apr2015

IVA

0.0

0.5

1.0

1.5

Apr2012Jul2012Sep2012Jan2013Apr2013Jul2013Sep2013Jan2014Apr2014Jul2014Sep2014Jan2015Apr2015

IVB

0.0

0.5

1.0

1.5

Apr2012Jul2012Sep2012Jan2013Apr2013Jul2013Sep2013Jan2014Apr2014Jul2014Sep2014Jan2015Apr2015

Abundance ('000s) per Km

Rainbow Trout Abundance Estimates By Reach

I – Glen Canyon/Lees Ferry

II – House Rock

III – Buck Farm

IVa – Upstream of LCR

IVb – Downstream of LCR

(Preliminary data from Korman and Yard 2015. Do Not Cite.)

Considerable declines in 

abundance in all reaches over 

Sept. 14 – Jan. 15 interval. 

Jan. & Apr. 15 estimates 

downstream of LCR below 

NNFC trigger.