Updates on LCR Channel Catfish and 

Laboratory Predation Studies

Annual Reporting Meeting, Jan 2022

David Ward, Eric Frye, Laura Tennant, Clay Nelson

U.S. Geological Survey, Southwest Biological Science Center, 

Grand Canyon Monitoring and Research Center
1. Project Title:

Warm Water native and non-native fish research and monitoring

Requested Elements

2. Project Elements

Project I.3 FY 21-23 workplan 

3. Project Objectives

Quantify the potential impacts Cannel Catfish and other non-native 

predatory fishes on native fish in the Little Colorado River.

4. Funding amount and Source

$133,000 – GCDAMP

5. Cooperators

AZ Game and Fish, U.S. Fish and Wildlife Service, Navajo Nation

6. LTEMP Resource Goals addressed

Conserve and protect native fishes
It’s a Fish eat Fish World

What is eating what?

And how much?

At what life stage?
Effects of Carp on eggs?

2020 X 2

6 tanks with carp

3 tanks without carp
2020 Common Carp predation on HBC eggs

Treatment

Carp No Carp

Number of surviving HBC larvae

0

100

200

300

400

Mean = 309

Range 152 - 452

Mean = 9.5

Range 0 - 24

*Provisional Data – do not cite

96 % average decrease in egg and larval survival
2021 Scale up X 10

X 2
2021 Common Carp predation on HBC eggs and Larvae 

Carp No Carp

Number of surviving HBC larvae

-400

-200

0

200

400

600

800

1000

Mean = 467

Range 115 - 1085

Mean = 61

Range 7 - 133

*Provisional Data – do not cite

87 % average decrease in egg and larval survival
Predation at all Life Stages
LCR Channel 

Catfish
2021 LCR 

• 6 Angling trips (May-July)

• 83 Channel Catfish Caught

• Average Size 450 mm 

TL (Range 300-660 mm TL)

• Only 7 Recaps

• Pop Estimate (Lincoln-Petersen)

• 1,274 (687-1,861 95 % CI) ?

• 14.5 % of fish (12 out of 83) caught had fish 

remains in stomach (from gastric lavage)

Size distribution of channel catfish in the Little Colorado River

Total Length (mm)

100 200 300 400 500 600 700

Frequency

0

2

4

6

8

10

*Provisional Data – do not cite
Back of envelope Calculations

• 600 Channel Catfish (low end of estimate)

• 10% eat a native fish every 24 hours

60 fish eaten/day

X

100 days of warm water (above 20 C)

= 6,000 fish eaten/year

Translocations ?? 300 -600 fish

About 10K HBC in LCR 

Relative impacts of Catfish – Potentially High!
Angling vs Antenna Recaptures

• Angling recaps (7) – all within few hundred meters

• Antenna recaps

Movement of Channel Catfish in the LCR

Distance (km)

0 2 4 6 8 10

Frequency

0

2

4

6

8

10

12

14

16

*Provisional Data – do not cite

33 Fish detected on antenna’s
Predation at all Life Stages
Laboratory Predation Studies

1,000-gallon raceways
Difference in predation vulnerability

Prey Species

Flannelmouth sucker Humpback chub

% Survival

0

20

40

60

80

100

X4

6 6

Photo by Jan Boyer 

AZGFD

4X

*Provisional Data – do not cite
Difference in predation vulnerability

Prey Species

Razorback sucker Humpback chub

% Survival

0

20

40

60

80

100

Photo by Jan Boyer 

AZGFD

*Provisional Data – do not cite
Difference in predation vulnerability

Prey Species

Desert Sucker Bonytail 

% Survival

0

20

40

60

80

100 Photo by Jan Boyer 

AZGFD

*Provisional Data – do not cite
Sucker vs chub survival with Channel Catfish

Total Length (TL)

60 80 100 120 140 160

Survival (%)

0

20

40

60

80

100

Sucker survival

Chub survival

*Provisional Data – do not cite

Laboratory 

Predation 

Studies
*Provisional Data – do not cite

2020 Small-bodied predators

Predator Total Length (mm)

30 40 50 60 70 80 90 100

Probability of Survival (%)

0

20

40

60

80

100

Plains Killifish

Red Shiner

Fathead Minnow

Green Sunfish

Survival of larval humpback chub (12 mm TL) as predator size increases for four species of small-bodied predatory fish commonly found in the Little 

Colorado River. Probability of survival calculated using JMP Prediction Profiler, based on 10 replicated 24-hr laboratory trials for each predator species 

(4 predators and 12 prey in each trial).
2021 Smallmouth Bass vs Green Sunfish

Total Length (TL)

50 100 150 200 250 300

Probability of Survival (%)

0

20

40

60

80

100

120

Predation vulnerability of a 60 mm TL humpback chub in 24-hr laboratory trials

*Provisional Data – do not cite
Smallmouth vs Green sunfish Gape comparison

TL

60 80 100 120 140 160 180 200 220

Gape (mm)

5

10

15

20

25

30

35

40

*Provisional Data – do not cite
Where are these introduced predators coming from ?

2019 - Dry

2021

What’s coming down 

the LCR with Flooding?

Questions?