U.S. Department of the Interior

U.S. Geological Survey

Humpback chub in the Colorado River: 

Status and Trends of Aggregations, 

Changes in Range

William R. Persons, USGS

David R. VanHaverbeke, USFWS

Michael Dodrill. USGS

Brian Healy, NPS
OUTLINE:

 Aggregation criteria

 Aggregation locations

 Chub with eggs

 Translocations

 Trends in relative abundance

 Long term monitoring
Aggregation: 

“a consistent and disjunct 

group of fish with no 

significant exchange of 

individuals with other 

aggregations, as indicated 

by recapture of PIT-tagged 

juveniles and adults and 

movement of radio-tagged 

adults”

(Valdez and Ryel, 1995).
What characterizes an aggregation?

1. No significant exchange of individual chub 

with other aggregations.

2. Persistence of the same individuals within 

an aggregation (site fidelity).

3. Presence of chub in spawning condition.
Map courtesy of Tom Gushue, GCMRC

30M

LCR

BAC

SHI

STE

MGG

HAV

PUM

LCH

Original 1996
Humpback chub exchange 1989-2014 

LOCATION RECAPTURED

Location 

Marked

N

Marks 30M

LCR

-In LCR BAC SHI STE MGG HAV PUM Site 

Fidelity

30M 162 43 0 1 0 0 0 0 0 0 89%

LCR-Inflow 6250 7 1417 2449 0 0 1 1 1 0 40%

LCR 48941 4 1815 21413 1 1 1 1 3 0 91%

BAC 33 0 3 5 0 0 0 1 0 0 0%

SHI 1233 0 2 8 0 139 3 6 0 0 93%

STE 98 0 0 1 0 1 1 1 0 0 19%

MGG 370 0 1 8 0 2 2 68 0 0 85%

HAV 1492 0 3 5 0 0 0 1 64 0 91%

PUM 41 0 0 0 0 0 0 0 0 3 100%

Total 58620 54 3241 23890 1 143 8 79 68 3

PRELIMINARY DATA, SUBJECT TO REVISION, DO NOT CITE
LOCATION RECAPTURED

Location 

Marked N

Marked 30M

LCRIn LCR BAC SHI STE MGG HAV PUM Site 

Fidelity

30M 162 43 0 1 0 0 0 0 0 0 89%

LCR-Inflow 6250 7 1417 2449 0 0 1 1 1 0 40%

LCR 48941 4 1815 21413 1 1 1 1 3 0 91%

BAC 33 0 3 5 0 0 0 1 0 0 0%

SHI 1233 0 2 8 0 139 3 6 0 0 93%

STE 98 0 0 1 0 1 1 1 0 0 19%

MGG 370 0 1 8 0 2 2 68 0 0 85%

HAV 1492 0 3 5 0 0 0 1 64 0 91%

PUM 41 0 0 0 0 0 0 0 0 3 100%

Total 58620 54 3241 23890 1 143 8 79 68 3

Humpback chub persistence 1989-2014 

PRELIMINARY DATA, SUBJECT TO REVISION, DO NOT CITE

{
PRELIMINARY DATA, SUBJECT TO REVISION, DO NOT CITE

Gravid humpback chub locations
Location

No 

significant 

exchange Site fidelity Ripe Adults

30M

LCR

BAC

SHI

STE

MGG

HAV

PUM

Scorecard 

PRELIMINARY DATA, SUBJECT TO REVISION, DO NOT CITE
30 Mile: expansion/discovery

PRELIMINARY DATA, SUBJECT TO REVISION, DO NOT CITE
Diamond Down Expansion

PRELIMINARY DATA, SUBJECT TO REVISION, DO NOT CITE
Map courtesy of Tom Gushue, GCMRC

30M

LCR

BAC

SHI

STE

MGG

HAV

PUM

LCH

Original 1996
Modified 2015

PUM

HAV

MGG

SHI

LCR

30M

STE

BAC

LCH
Translocations contribute to mainstem 

Cumulative number of fish translocated

PRELIMINARY DATA, SUBJECT TO REVISION, DO NOT CITE
Where do translocated fish go?

LCR

PRELIMINARY DATA, SUBJECT TO REVISION, DO NOT CITE
Modeling CPUE with GLMs

 

 Generalized Linear Models (GLMs)

 Handle catch (count) and effort data

 Allow for model comparison with AIC
Modeling CPUE with GLMs

 

 Generalized Linear Models (GLMs)

 Handle catch (count) and effort data

 Allow for model comparison with AIC

 Period: (1991 – 1993), (2002 – 2006), (2010 – 2014) 

 Location: 5- mile sections of river 

 Aggregation: Is a location an aggregation? 

 Year: Sampling year 
Modeling CPUE with GLMs

 

PRELIMINARY DATA, SUBJECT TO REVISION, DO NOT CITE

Model ΔAICc K

Gear + Period + Location + LCR Inflow : Period 0 23

Gear + Period + Location 4.24 21

Gear + Year + Location 12.84 31

Gear + Period + Aggregation + LCR Inflow 18.32 7

Gear + Year + Aggregation + LCR Inflow 27.2 17

Gear + Period + Aggregation 32.94 6

Gear + Year + Aggregation 40.46 16

Gear + Location 64.66 19

Gear + Aggregation + LCR Inflow 74.39 5

Gear + Aggregation 80.17 4

Gear + Period + LCR Inflow 116.07 6

Gear + Year + LCR Inflow 132.61 16

Gear + LCR Inflow 173.61 4

Gear + Period 177.26 5

Gear + Year 191.11 15
PRELIMINARY DATA, SUBJECT TO REVISION, DO NOT CITE
Antennas

Pilot Project 2014

•@ $2,400 

• 6 - 7 d battery life

• >10-in read range

Trip Chub

July 73

September 98

PRELIMINARY DATA, SUBJECT TO REVISION, DO NOT CITE
Increasing abundance and distribution:

 Warmer than normal water during 2004, 2005, 2011, 

2014

 Translocations 

 Shinumo and Havasu Creeks 

 Mechanical trout removal at LCR confluence 2003-

2006, 2009

 Good production of humpback chub from Little 

Colorado River

 We find humpback chub where we look for them
Baited hoop nets

Seines

Antennas

Sample widely

Long term monitoring