The Feasibility of Augmenti

the Grand Canyon Populatio

Humpback Chub (Gila cyph

by

David R. Van Haverbeke

and Robert L. Simmonds, Jr.

US Fish and Wildlife Service
The humpback chub
Rationale

• Report stemmed from AMWG reque

determine feasibility of establishing a captive broodstock.

• Report was extended to include grow

out wild caught age-0 fish for release into the wild, and translocations.
Closed abundance estimate

Little Colorado River since 1

0

1,0002,0003,0004,0005,0006,0007,0008,000

Apr-92 May-92 Jun-92 May-01 April/May

2002

April/May

2003

Date

Abundance
Three alternatives discuss

• 1. Development of a captive broodst• 2. Capture of wild age-0 fish for grow 

and release back into the wild.

• 3. Translocations above Chute Falls 

to other tributaries in Grand Canyon
Captive broodstock: two 

approaches

• 1. Captive broodstock for use as a g

refugium – risk free.

• 2. Captive broodstock used for stock

back into the wild – numerous biologrisks involved.
Biological risks of captive 

broodstock:

• Introgression• Inbreeding depression• Decreasing the wild Ne at large• Domestication
Prerequisites of captive brood

program:

• Will likely require a facility large eno

hold several thousand fish.

• Will need a quarantine facility.• Development of a formal captive 

broodstock management plan.
Where to begin right now

• The Willow Beach fish (~ 80 are left) 

function as a beginning point.

• This will require some genetics work 

completed or that will need to be performed.
Captive broodstock:

• Needs to be identified in a Recovery Plan 

recovery option.

• Should be a last resort based on USFWS

policy statements, and the scientific commat large.

• Basically, habitat restoration should be a 

priority before captive broodstock.
Grow out of wild caught age-0 

for supplemental stocking

• Advantages – bypasses many of the 

serious risks associated with captive broodstock.

• Risks – Some minor risks associated 

ethology, and density dependant issthe wild. 
Strategy

• Collect wild age-0 fish from the Little 

Colorado River.

• Grow in captivity under natural reari

conditions until 150+ mm

• Release back into the wild on an an

basis.
Potential objectives

• Maintain populations at levels found 

2000.

• Recover fish to levels found in early 

1990s. 
Modeling: ~1,400 fish/ye

0

2000400060008000

100001200014000

1990 1995 2000 2005 2010 2015 

Year

Number of Fish 

age 1 recruits Age 4+ spawners
Translocations

• Above Chute Falls• Other tributaries in Grand Canyon
Chute Falls

• Activities already begun• Risks – some risks for eventual inbreedin• Benefits – Population expansion, range 

expansion, promotes a self-sustaining population. 
Other Tributaries

• Havasu, Shinumo, and Bright Angel• There may be potential for large 

abundance increases if combined wwith mechanical removal
Priority Conclusions

• Translocations already begun. • Grow out of age-0 may require 1,000

5,000 fish per year to achieve goalsrelatively risk free.

• Captive broodstock should be last re

because of high potential for biologicrisks.
Thank you!

• Thanks to Chester Figiel at Willow B

National Fish Hatchery, Manuel UlibDexter National Fish Hatchery, Carl Walters at University of British Columand to numerous people who providinsight and suggestions for this repo

• randy_vanhaverbeke@fws.gov