Lees Ferry fishery

David Rogowski, Arizona Game and Fish Department

Jan Boyer, Arizona Game and Fish Department

Crosby Hedden, Arizona Game and Fish Department

Lauren Mason-Sarantopulos, Arizona Game and Fish Department

Lucas Bair, USGS, Southwest Biological Science Center, Grand Canyon 

Monitoring and Research Center
AZGFD Lees Ferry Monitoring

• Project Elements

• Project H: Salmonid Research and Monitoring

• Project I: Warmwater Native and Nonnative Fish Research and Monitoring

• Project J: Socioecononomic Research in the Colorado River Ecosystem

• Project Objectives

• Long term monitoring of trout population

• Assess angler use of fishery

• Detect warmwater invasive species

• Funding Amount and Source: GCDAMP $88,000, supplemented with AZGFD 

D-J Funds

• Cooperators: USGS, GCDAMP, NPS

• Products: Annual Reports, presentations, publications
LTEMP resource goals

6. Recreational Experience. Maintain and improve the quality of recreational experiences 

for the users of the Colorado River Ecosystem. Recreation includes, but is not limited to, 

flatwater and whitewater boating, river corridor camping, and angling in Glen Canyon. 

9. Rainbow Trout Fishery. Achieve a healthy high-quality recreational rainbow trout fishery 

in GCNRA and reduce or eliminate downstream trout migration consistent with NPS fish 

management and ESA compliance.

10. Nonnative Invasive Species. Minimize or reduce the presence and expansion of aquatic 

nonnative invasive species.
Lees Ferry Fishery Management Plan

• Maintain a healthy population of Rainbow Trout at Lees Ferry to support 

recreational fishing

• Rainbow Trout ≤ 6 inches compose 20-50% of the Lees Ferry population as determined 

by fall electrofishing

• Rainbow Trout electrofishing CPUE exceeds 1 fish per minute

• Quality trout fishing experience 

• Angler catch rate ≥ 1 Rainbow Trout per hour

• Grow quality sized trout that are available to the angler

• In 10 hr day, angler catches at least 10 Rainbow Trout ≥ 14 inches and one ≥ 20 inches

• trout condition factor ≥ 1 during summer
Objectives

• Long term monitoring of trout population

• Assess angler use of fishery

• Detect warmwater invasive species
Methods

• Standardized electrofishing:

• spring, summer, fall

• Nonnative hunt (summer, fall)

• Angler surveys (creel): 

• 6 days/month

• Citizen science

• Game camera
Electrofishing – catch 2021

Species Standard

Monitoring Nonnative hunt total % catch standardmonitoring

Rainbow Trout 794 0 794 68.7

Brown Trout 322 6 328 27.8

Flannelmouth 

Sucker 36 0 36 3.11

Common Carp 4 17 21 0.346

Green Sunfish 0 2 2 0

Walleye 0 3 3 0
Rainbow Trout CPUE 
Rainbow Trout 

CPUE by size 

class
Fall Rainbow Trout 

length frequency

histograms

2016-2021
Rainbow Trout relative 

condition (Kn) by size class
Rainbow Trout 

relative condition 

(kn) and abundance 

(CPUE)

Rainbow Trout (150-305 mm TL)

CPUE (fish/minute)

Rainbow Trout (150

-305 mm TL)

Relative condition (kn

)
Brown Trout

https://westernnews.media.clients.ellingtoncms.com/img/photos/2020/11/03/Browntrout029.jpg
Location 

of Brown 

Trout 

captured

2021
Brown Trout length 

frequency

histograms

2010-2021
Brown 

Trout 

relative 

condition 

(Kn)
Relative 

condition of 

Brown Trout 

and Rainbow 

Trout
Brown Trout relative 

condition and CPUE 

(fish/min) of Rainbow 

Trout (<152 mm TL)

https://flycurrents.blogspot.com/
2021 

Angler 

surveys 

(creel)

• AGFD/GCMRC

• 143 days, 2033 

anglers

• Walk-in area 

(n=440)

• Boat ramp 

(n=1593)

Preliminary data and results do not quote or cite
Relative angler use
2021 Demographics

Number of anglers

(%)

Mean age

(median age)

Male Female Male Female

Boat

1502

(87.8%)

209

(12.2%)

48.8

(50)

44.4

(45)

Walk-in

335

(75.1%)

111

(24.9%)

41.2

(40)

29.8

(29)

Preliminary data and results do not quote or cite
Age/Sex of 

anglers at Lees 

Ferry

Preliminary data and results do not quote or cite
Fish captured by anglers!

Species Number Harvested % harvested

Rainbow Trout 7,711 192 2.49

Brown Trout 273 67 24.5

Flannelmouth 

Sucker 12 1 8.3

Channel Catfish 2 1 0.50

Preliminary data and results do not quote or cite
Angler 

CPUE 

(fish/hr) for 

Rainbow 

Trout

Preliminary data and results do not quote or cite
Percent anglers that caught at least one 

fish:

• Boat anglers: 76 %

• Walk-in anglers: 34 %

Preliminary data and results do not quote or cite
Angler surveys – Brown Trout

Year Anglers

interviewed Anglers Caught Harvested % Harvested

2014 1650 10 14 2 14

2015* 1999 20 23 3 13

2016+ 1214 5 6+ 1 17

2017 1254 26 30 8 27

2018 1325 47 96 14 15

2019 1250 95 165 37 22

2020 1509 114 301 34 11

2021* 2033 134 273 67 24

* Extra days of creel

+likely underreported due to bad publicity on social media in relation to NPS mandate for scientists to euthanize any Brown Trout captured during monitoring efforts

Preliminary data and results do not quote or cite
Citizen science project

• 6 private anglers participated

• 127 unique trips

• 1,106 Rainbow Trout captured and measured 

• Mean TL 308 mm [302, 307]

• Mean TL 12.0 inches [11.9, 12.1]

• 25 Brown Trout captured and measured 

• Mean TL 392 mm [368, 417]

• Mean TL 15.4 inches [14.4, 16.4]

Preliminary data and results do not quote or cite
Citizen Science 2021

Preliminary data and results do not quote or cite
Summary

• Rainbow Trout relative abundance is the lowest ever recorded

• Recruitment has been declining since 2017

• Brown Trout relative abundance is similar to last year (increasing 

recruitment?)

• A few warmwater non-natives present

• Lees Ferry Rainbow Trout fishery is not meeting AZGFD management goals:

• CPUE electrofishing was less than 1 fish/min

• Angler catch rates < 1 fish/hour

• Anglers did not catch 10 Rainbow Trout ≥ 14 inches and one ≥ 20 inches

• Rainbow Trout condition (kn) was ≥ 1 in summer 
Acknowledgements

• GCMRC-USGS: A.M. Bringhurst, C. Nelson, S. Felder, and L. Bucci

• Ceiba: J. Swindlehurst

• Volunteer: M. Morton

• AZGFD: R. Chadwick, A. Feddern, S. Pierce, 

• S. Harding
Incentivized Harvest

• Began November 2020

https://thumbs.dreamstime.com/b/dollar-fish-22133555.jpg https://www.tu.org/wp-content/uploads/2021/07
Incentivized 

Harvest

• Creel questions

1. Were you aware of the 

incentivized harvest program 

when planning your trip?

2. Were you intending to 

participate in the incentivized 

harvest program when you 

started your trip?

----Number of Brown Trout submitted

Preliminary data and results do not quote or cite
Incentivized Harvest Bonus Bonus Bonus

$$$

BNT Date Item Award amount

11 Nov 

2020

Implemen

tation $25/fish

AprilMay 

2021

Increase 

award 

amounts

$33/fish, $50/3 fish, 

$50/PIT tagged fish, 

$300/sonic tagged 

fish; $500/most, 

$250/best video

Aug 

2021 Bonus $50 bonus for 3 fish

Sept. -

Dec 2021 Bonus

$50 bonus for 3 fish, 

$300 for PIT tagged 

fish

Dec. 

2021 Bonus

$50 bonus for 3 fish, 

$300 for PIT/sonic 

tagged fish; $500 for 

most, $500 for largest 

Preliminary data and results do not quote or cite