U.S. Department of the Interior

U.S. Geological Survey

Early life history of humpback 

chub: patterns and potential 

drivers

Annual Reporting for FY14

January 21, 2015

Charles B. Yackulic* (U.S.G.S. – GCMRC) and

Maria Dzul (U.S.G.S. – GCMRC)

* Presenter – email: cyackulic@usgs.gov
Outline

 JCM survival

 Early life history in the Little Colorado River

 Survival and growth in the Colorado River
HBC survival in JCM reach

Preliminary Data Do Not Cite

Results from traditional approach...assume each 

year has its own survival rate
HBC survival in JCM reach

Preliminary Data Do Not Cite

Same results expressed on monthly base...model 

assumes “steps” in survival.
HBC survival in JCM reach

Preliminary Data Do Not Cite

Using a slightly different approach 

(Bayesian) we can get estimates for each 

interval between sampling.
More or less agree.

Preliminary Data Do Not Cite
HBC survival in JCM reach

Preliminary Data Do Not Cite

If we model survival based on covariates, there is 

quite a bit more variation.
HBC survival in JCM

Preliminary Data Do Not Cite

Patterns with covariates are similar 

to Bayesian model when aggregated 

and scaled to interval level.
HBC survival in JCM

Preliminary Data Do Not Cite

Patterns with covariates are also 

similar at annual scale...but model is 

better supported by data. (same K)
Drivers of HBC early life history

 In the LCR – flooding and intrinsic factors

 Production

 Emmigration rate

 Growth 

 CR – potentially many factors

 Immigration

 Trout?

 Temperature?

 Turbidity?

 Discharge?

 Growth
Drivers of HBC early life history

 In the LCR – flooding and intrinsic factors

 Production

 Emmigration rate

 Growth 

 CR – potentially many factors

 Immigration

 Trout?

 Temperature?

 Turbidity?

 Growth
LCR Recruitment LCR Fall 

Abundance

Additions

to CR

ggoo

sstttttt

Time

mmoooo oooo
Fall HBC abundance in the LCR

Preliminary Data Do Not Cite

Modified from Van Haverbeke et al. (Annual Reporting 2013)
LCR Recruitment LCR Fall 

Abundance

N

Additions

to CR

ggoo

sstttttt

Time

mmoooo oooo
Analyzing abundances suggests highly 

variable export, which appears related to fall 

abundances in LCR. 

Preliminary Data Do Not Cite

?
LCR Recruitment LCR Fall 

Abundance

N

Additions

to CR

ggoo

sstttttt

Time

mmoooo oooo
July LCR juvenile HBC abundance estimates:

2013: 14,000 (95% CI: 11,000-17,000)

2014: 11,000 (95% CI: 9,500-13,000)

2 4 6 8 10 12 14

0

500

1000

1500

2000

2500

Subreach

Abundance of HBC (40-99mm TL)

Boulders Coyote Salt 2013

2014

Two years of 

July LCR trips 

have likely been 

low years with 

little export.

Preliminary Data Do 

Not Cite
LCR Recruitment LCR Fall 

Abundance

N

Additions

to CR

ggoo

sstttttt

Time

mmoooo oooo
Estimates of emigration seem to line up more or less with 

increases in abundance

Preliminary Data Do Not Cite
Drivers of HBC early life history

 In the LCR – flooding and intrinsic factors

 Production

 Emmigration rate

 Growth 

 CR – potentially many factors

 Immigration

 Trout?

 Temperature?

 Turbidity?

 Growth
Dzul et al., available online

 0 2 6 19 54

Number of days with flooding (log scale)

Winter growth of humpback chub in 

LCR closely linked to amount of 

flooding (scouring?).
Growth effects size of humpback chub when they emigrate 

from LCR and could explain winter emigration.

Preliminary Data Do Not Cite
Drivers of HBC early life history

 In the LCR – flooding and intrinsic factors

 Production

 Emmigration rate

 Growth

 CR – potentially many factors

 Immigration

 Trout?

 Turbidity?

 Temperature?

 Growth
HBC survival in JCM reach

Preliminary Data Do Not Cite
Potential monthly covariates 

considered

CJS - 2009 – 2014

 Estimates of trout N

 Temperature

 Proportion of juveniles > 80 mm

 Turbidity 

 > 10 NTU

 > 50 NTU

 >100 NTU

 Stage

 Average

 Standard Deviation

 Interactions

mini-multistate - 2012 – 2014

Growth and Survival

 Temperature

 Turbidity 

 > 10 NTU

 > 50 NTU

 >100 NTU

 Stage

 Average

 Standard Deviation

 Size

 Interactions
mini-multistate - 2012 – 2014

Survival

 Size(+)

 Turbidity (>10 NTU) (-)

Growth

 Temperature (+)

 Average Stage (Discharge) (+)

 Size (-)
Preliminary Data Do Not Cite

HBC survival in JCM reach
Preliminary Data Do Not Cite

HBC length frequency in JCM reach
Temperature

Monthly growth of a 

60-80 mm humpback 

chub

Growth (mm)

Preliminary Data Do Not Cite
CJS - 2009 – 2014

 Proportion of larger 

juveniles (+) 

 Estimates of trout N (-)

 Turbidity (> 10 NTU) (-)

 Interaction between 

Turbidity and Trout (+)

mini-multistate - 2012 – 2014

Survival

 Size(+)

 Turbidity (>10 NTU) (-)

Growth

 Temperature (+)

 Average Stage (Discharge) (+)

 Size (-)
Preliminary Data Do Not Cite

HBC survival in JCM reach
Juvenile chub take home messages

 Flooding in the LCR plays a critical role in 

production, outmigration and growth. 

 Growth in the Colorado River primarily driven 

by temperature, but may also be affected by 

monthly volumes / stage. 

 Survival appears to be a function of fish size, 

trout and turbidity. 
Acknowledgements

 Mike Yard , Josh Korman

 US Fish and Wildlife Service 

 Near Shore Ecology Group

 David Ward, Luke Avery, Michael 

Dodrill and others involved with July 

LCR

 Glen Canyon Adaptive Management 

Group

 Bureau of Reclamation

 Navajo Nation Department of Fish 

and Wildlife

 National Park Service