Humpback Chub in the Little Colorado 

Monitoring of Juveniles, Sub-Adults, 

Adults and Translocations

David Van Haverbeke, Kirk Young, Denn

Stone, Mike Pillow - USFWS
Objectives

 1) Address Project 7: Population Ecology of Humpba

in and around the Little Colorado River

 Conduct long term monitoring of Humpback Chub (G

cypha, HBC) and other fishes in the lower 13.56 km Little Colorado River (LCR).

 2) Address Project Element 8.2. Translocation and m

of Humpback Chub above Chute Falls in the Little CRiver

 Annually translocate juvenile Humpback Chub to abo

Falls and monitor.
Little Colorado River Humpback C

hoop net monitoring
Effort

Typical trip = ~13.8 net sites/km minimu

~540 net nights/trip or ~12,500 net hours/t
Observed species composition in 

using hoop nets (2000-2016)
Annual spring abundances of Humpback 

≥150 mm and 

≥200 mm in lower 13.6 km o
Annual spring abundances of Humpback 

150-199 mm in lower 13.6 km of LCR

0

500

1,0001,5002,0002,5003,0003,500

May/June 2001

April/May 2002

April/May 2003

April/May 2004

April/May 2005

April/May 2006

April/May 2007

April/May 2008

April/May 2009

May/June 2010

May/June 2011

April/May 2012

April/May 2013

Abundance estimate

Year
Annual fall age 0 abundance (blue) and 

following spring age 1 abundance (re
Annual fall abundances of Humpback Chu

mm and 

≥200 mm in lower 13.6 km of L
Spring relative abundances (CPUEs

Bluehead Sucker (blue) and Flannelm

Sucker (red

)
Summary

 2015 and 2016 saw a significant apparent declin

number of sub-adult and adult Humpback Chub Little Colorado River.

 This apparent decline may be partially stemming 

lower production of age 0 chub in 2014 and 201

 There is also evidence that a higher number of s

and adult chub have been inhabiting the mainsteoutside of the LCR for the past two years. 
Summary

 These monitoring efforts provide an imm

(annual) indication of the status of all size of Humpback Chub in the Little ColoradRiver.

 Further, data collected from these monito

efforts are used to generate open populatmodels (ASMR, multi-state), without whthese other models would likely not be po
Translocations
Numbers and sizes of Humpback Chub col

from the Little Colorado River for transloca

(2003-2016)

Date Chute Falls * Size (mm) SNARRC Shinumo Havasu Size 8/1/03 283 50-100 7/30/04 299 50-100 7/29/05 567 50-100 7/22/08 299 ~80-130 207 <10/13/08 300 100 <17/24/09 194 ~80-130 205 83 <10/10/09 238 <17/16/10 108 ~80-130 175 <11/5/10 300 300 <11/9/11 96 ~80-130 200 300 <7/12/12 212 ~80-130 202 200 300 <5/24/13 73 <7/11/13 99 <11/7/13 303 ~80-130 11 300 <15/1/14 660 <10/31/14 305 65-137 <15/28/15 315 <11/1/15 303 10/27/16 137 58-146 Totals 3,106 1,082 1,311 2,175 
Above Chute Falls - Number of juvenile Hum

Chub translocated (black) and adult abund

(red & grey) 
Above Chute Falls - Number of juvenile Hum

Chub translocated (black) and adult abund

(red & grey) 
Below Chute Falls (Atomizer reach) - A

Humpback Chub abundances (red & gr
Below Chute Falls (Atomizer reach) - A

Humpback Chub abundances (red & gr
Growth of Humpback Chub from three L

Colorado River reaches
Apparent survival of translocated age 0 

vs those not translocated (provisiona

Survival of translocation cohorts during first year

Survival of translocohorts during seyear
Apparent survival of translocated age 0 

vs those not translocated (provisiona

Survival of translocation cohorts during first year

Survival of translocohorts during seyear
Summary

 Higher growth rates and increased survival a

to be a result of translocating fish to above CFalls. 

 Environmental stochasticity (floods/loss of h

may be one factor ultimately precluding permcolonization of Humpback Chub above Chut

 Translocations are relatively easy and inexp

beneficial conservation actions compared to options that may be much more expensive apolitically difficult to implement. 
Thank You