Monitoring Humpback Chub in the Little 

Colorado River and Colorado River, Grand 

Canyon

David Van Haverbeke, Maria Dzul, Charles 

Yackulic, Mike Yard, Kirk Young, Mike Pillow, 

Dennis Stone, Olivia Williams
Project G: Humpback Chub (HBC) Population 

Dynamics throughout the Colorado River Ecosystem

 Project elements and objectives:

 G.1: HBC population modeling

 G.2 Annual spring/fall HBC abundance estimates in the lower 13.6 km of 

the Little Colorado River (LCR)

 G.3. Juvenile HBC monitoring near the LCR confluence

 G.4 Remote PIT tag array monitoring in the LCR

 G.5. Monitoring HBC aggregation relative abundance and distribution

 G.6. Juvenile Humpback Chub Monitoring - West

 G.7. Chute Falls HBC translocations

 Funding Amount and Source: $1,172,824, AMP

 Cooperators: USGS, USFWS

 Resource Goals: Humpback Chub, Natural Processes, Other Native Fish
Presentation outline

(Project G)

 LCR aggregation

 Update on abundance (G.1, G.2, G.3)

 Incorporation of antennas into models (G.1, G.4) 

 Chute Falls translocations (G.1, G.7)

 Mainstem Grand Canyon

 HBC aggregations (G.5) 

 Fall Canyon (G.1, G.6)
Colorado River humpback chub life cycle
Monitoring in 

lower 13.57 km of 

LCR

Mainstem 

monitoring in 

juvenile chub 

monitoring (JCM) 

reach 

Provisional data. Do not cite.

Annual fall HBC age-0 abundance (blue) and the 

following spring age-1 abundance (red)

Provisional data: do not cite

Juvenile abundance in the JCM-reach (<100mm TL)

Provisional data. Do not cite.

Fall abundances of small subadult humpback chub 

in the JCM reach (100-149mm TL) 

Provisional data. Do not cite.
Fall abundances of large subadult humpback chub 

in the JCM reach (150-199mm TL) 

Provisional data. Do not cite.
Annual spring abundances of HBC 150-199 mm in 

lower 13.6 km of LCR

Provisional data. Do not cite.

Fall abundances of adult humpback chub in the 

LCR aggregation (>199mm TL) 

Provisional data. Do not cite.
Population growth rate for adult humpback chub in 

the LCR aggregation (>199mm TL) 

Provisional data. Do not cite.

Annual spring abundances of HBC ≥150 mm and 

≥200 mm in lower 13.6 km of LCR

Provisional data. Do not cite.
Annual fall abundances of HBC ≥150 mm and ≥200 

mm in lower 13.6 km of LCR

Provisional data: do not cite
Summary

 Juvenile humpback chub abundance was low 2016-18, 

but 2019 was a good production year in the LCR

 In the CR abundance trends are largely influenced by 

2011 & 2012 cohorts. Trends in the LCR are different 

from the CR.

 Subadult abundance is declining in the JCM reach due 

to low age-0 production from 2013-2018.

 Adult humpback chub population remains stable, though 

low abundance of subadults in JCM-east signals 

potential for future decline
Presentation outline

(Project G), cont.

 LCR aggregation

 Update on abundance (G.1, G.2, G.3)

 Incorporation of antennas into models (G.1, G.4) 

 Chute Falls translocations (G.1, G.7)

 Mainstem Grand Canyon

 HBC aggregations (G.5) 

 Fall Canyon (G.1, G.6)
Antenna data

Submersible PIT 

antennas in the CR 

(UFO)

Deployed during trips

PIT tag array in the LCR:

Multiplexer (MUX)

Deployed continuously
Fall abundances of adult humpback chub in the 

LCR aggregation (>199mm TL) 

Method 1: Treat unmarked and marked fish the same (physical captures only)

Method 2: Calculate abundance separately for marked and unmarked fish (uses 

antenna detections for marked fish)

Years when 

UFO 

antenna 

were 

deployed

Provisional data. Do not cite.
Results: Probability of skipped spawning

Provisional data. Do not cite.
Results: Survival

Provisional data. Do not cite.
Summary, cont.

 Antenna data provide useful information because 

they are increase detection probabilities, 

particularly for larger fish

 We hope to continue to use antennas and develop 

new mark-recapture methods for antenna data
Presentation outline

(Project G), cont. 2

 LCR aggregation

 Update on abundance (G.1, G.2, G.3)

 Incorporation of antennas into models (G.1, G.4) 

 Chute Falls translocations (G.1, G.7)

 Mainstem Grand Canyon

 HBC aggregations (G.5) 

 Fall Canyon (G.1, G.6)
Translocations and Chute Falls 

Monitoring
Numbers and sizes of Humpback Chub collected 

from the Little Colorado River for translocations 

(2003-2019)

Date Chute Falls * Size (mm) SNARRC Shinumo Havasu Size (mm) Total Capture Location Capture Location (km) Tag

8/1/03 283 50-100 283 Boulders ~1.15-3.15 VIE

7/30/04 299 50-100 299 Boulders ~1.15-3.16 VIE

7/29/05 567 50-100 567 Boulders ~1.15-3.17 VIE

7/22/08 299 ~80-130 207 <80 506 Boulders ~1.15-3.18 PIT

10/13/08 300 100 <130 400 Boulders ~1.15-3.18

7/24/09 194 ~80-130 205 83 <80 482 Boulders ~1.15-3.18 PIT

10/10/09 238 <130 238 Coyote ~7.56--9.85

7/16/10 108 ~80-130 175 <80 283 Boulders ~1.15-3.18 PIT

11/5/10 300 300 <80 600 Coyote ~7.56--9.85

11/9/11 96 ~80-130 200 300 <80 596 Coyote ~7.56--9.85 PIT

7/12/12 212 ~80-130 202 200 300 <80 914 Coyote ~7.56--9.85 PIT

5/24/13 73 <30 73 Boulders ~1.15-3.18

7/11/13 99 <80 99 Coyote ~7.56-9.85

11/7/13 303 ~80-130 11 300 <130 614 Coyote ~7.56-9.85 PIT

5/1/14 660 <30 660 Riverwide 0-13.56

10/31/14 305 65-137 <130 305 Coyote ~7.56-9.85 PIT

5/28/15 315 <30 315 Riverwide 0-13.56

11/1/15 303 61-128 303 Coyote ~7.56-9.85 PIT

10/27/16 137 58-146 137 Coyote ~7.56-9.85 PIT

6/16/17 139 <40 139 Riverwide 0-13.56

10/26/17 315 66-120 315 Coyote ~6.9-10.5 PIT

10/29/18 49 63-115 49 Coyote ~6.9-10.5 PIT

6/18/19 250 400 <40 650 Coyote ~6.9-10.6 N/A

10/24/19 306 52-94 306 Coyote ~6.9-10.5 PIT

Totals 3,776 1,471 1,711 2,175 9,133

Provisional data: do not cite
Above Chute Falls - Number of juvenile HBC 

translocated (black) and adult HBC >=200 mm 

abundances (red & grey) 

Provisional data: do not cite Provisional data. Do not cite.
Growth (mm/day) of HBC in Chute Falls, Atomizer, 

and Lower reaches of LCR (Stone et al., in review)

Provisional data: do not cite
HBC reach adulthood significantly faster in the 

Chute Falls and Atomizer reaches than in Lower 

LCR (Stone et al., in review)

Provisional data: do 

not cite
Comparing translocations to trout removals

Provisional data. Do not cite.
Summary, cont. 2

 Significantly higher growth rates are a result of 

translocating HBC to above Chute Falls. 

 With higher growth rates comes significantly 

quicker time to reach adulthood (hence a 

headstart for reproduction). 

 Translocations are relatively easy and inexpensive 

beneficial conservation actions compared to other 

options that may be much more expensive and 

politically difficult to implement.
Presentation outline

(Project G), cont. 3

 LCR aggregation

 Update on abundance (G.1, G.2, G.3)

 Incorporation of antennas into models (G.1, G.4) 

 Chute Falls translocations (G.1, G.7)

 Mainstem Grand Canyon

 HBC aggregations (G.5) 

 Fall Canyon (G.1, G.6)
Mainstem HBC monitoring
Map of humpback chub aggregation sites 
CPUE of HBC and FMS at sampling sites 

during 2019 aggregation sampling

Provisional data: do not cite
Effort (# nets) and catch of FMS and HBC on 

aggregation trips (2000 and 2010-2019)

Provisional data: do not cite
CPUE (fish/net) of adult HBC at sampling sites 

in western Grand Canyon (below 156 mile) 

Provisional data: do not cite
Fall abundance estimates in JCM-west 

(Fall Canyon)

Provisional data. Do not cite.
Closed vs open model abundance estimates of 

HBC by size class in JCM West reach 

August/September 2019 

Provisional data. Do not cite.
2018 and 2019 density estimates (fish/mile) of 

HBC at Bridge City (2 mile reach)

Provisional data: do not cite
Summary, cont. 3

 CPUEs of HBC and FMS have been increasing recently 

in Grand Canyon, particularly in western Grand Canyon 

below Havasu Creek. This is a recent phenomenon. 

 Since 2017, we have conducted closed mark recapture 

studies on HBC and FMS at four sites on mainstem

aggregation trips: JCM East, JCM West, Bridge City, and 

250 mile, and open modeling at JCM East and JCM 

West. 
Thank You