Chute Falls Humpback Chub Translocations 

Objectives, Effectiveness and Future Work

22 January 2013

Kirk Young - USFWS
C.F. Translocation Outline

 Background

 Project Objectives

 Results/Knowledge and Effectiveness

 Future Work

Little Colorado River

Chute Falls

14.1 km Lower Reach

Upper Reach
Background

Chute Falls:

 No HBC above Chute Falls – fish barrier

 High CO2 levels – prevent HBC?

 High productivity and higher winter Temps

Translocation:

 Translocations began 2003; 8 to date 

 2,060 HBC over 10 years 

 ~1,217 PIT tagged 

 Annual Monitoring – Hoop Nets
Objectives

2003-2005 Translocations

 Determine if HBC can survive and remain above 

Chute Falls;

 Determine if HBC grow (given increased food 

availability, but potential detrimental impacts from 

CO2);

 Determine if HBC can recruit to adulthood;

 Determine if HBC spawning population will develop.
Objectives

2006-current

 Conduct mark/recapture population estimates –

2 reaches (>CF and LA to CF) to determine:

 Migration patterns

 Growth rates

 Spawning activity

 Assess overall benefit to LCR HBC
Results

Survival

 Several HBC found above CF > 4 years 

(6 years - max)

 Fish detected upstream to rkm 17.89 

 >3.5 km above CF; 1.5 km above release site

 Most fish vacated >CF during 2009-2010 Exodus 
Results

Growth

2003-05 Translocated HBC

GCMRC LCR Growth Model 

126

101

86

48

2 1

8

21
Results

Spawning 

Above CF:

 > 200 HBC in Spawning Coloration (116F; 99M)

 6 Females (ripe, gravid or spent)

 142 males ripe

 3 YOY (54-63 mm) in 2007

 Spawning appears to occur, probably transient; 

fish could be moved out by spring freshets 
Results 

Migration Patterns

 Chute not barrier 

5 fish surmounted; 

 Movement 

throughout, including

Colorado R.

Results 

What is Benefit to LCR HBC

 Not fully quantified yet, but potentially large 

 Pop Estimates and Survival/mortality estimates 

key

Here’s what we know.....
Abundances of Humpback Chub ≥ 200 mm 

above and below Chute Falls
June 2010

October 2012
LCR - Spring Abundance of HBC 

≥ 150 mm and ≥ 200 mm
Results 

Mortality/Survival rates? 

Coggins et al. 2006: 68% mortality/32% survival age 2; 

Age 0 & 1 mortality > but not quantified 
Results 

Benefit to LCR HBC 

Survival Rates, monitoring data -- AGE 1 Fish:

Trans YR Number Recap YR

Recap 

Number % Survival

2008 299 2009 214 >71%

2010 109 2011 50 >46%

2011 96 2012 59 >61%

Coggins et al. 2006 (age 2) <32%

Results 

Benefit to LCR HBC

 Assuming survival is Greater @ CF:

Scenario: 

1/2 LCR Mortality (Coggins); 

1000 fish translocated @ age 1

Age 2 Age 3 Age 4

After 1 

YR

After 2 

YRS

After 3 

YRS

Chute Falls

(50% LCR Mort.) # Survive 625 413 314

Little Colorado

(Coggins et al. 2006) # Survive 250 80 42
Results 

Chute Falls Translocation – Knowledge Summary

 Fast Growth - Adult at Age 2 vs. Age 3

 High Survival 

 High Potential to recruit to adult

 Some evidence spawning may occur

 Evidence for good retention during most years

 Populations susceptible to stochastic events 

(interruption/emigration) 

 Appears to be one of few tools available to directly 

increase adult population if needed in future
Needs

 Refine Survival/Mortality & Recruitment to adult 

 Define Optimal Translocation Densities

 YOY translocation

 Age 1

 Understand Spawning 

Component 

 Natural Recruitment

 Fidelity

 Genetics 
Thank You 

Questions?