Arizona Game & Fish Dep

Lees Ferry long term mon

David Rogowski C. Madonia, K. Manuell, R. Osterhoudt, L. Winters, P. Wolters 

Photo – Lees 

Guiding documents 

• Comprehensive Fisheries Management Plan fo

Canyon and Grand Canyon (National Park Servic

2013) 

• Lees Ferry Recreation Trout Fishery Managem

Recommendations: The Voice of Lees Ferry Recre

Anglers, Guides and Businesses, August 2015 

• Fisheries Management Plan, Colorado River-L

Ferry. Arizona Game and Fish Department, Septemb

• National Park Service Research Permits 

1. maintain a healthy population of Rainbow 

Lees Ferry to support recreational fishing 

1. Rainbow Trout 

≤ 6 inches compose 20-50% o

Ferry population as determined by fall electro

2. Rainbow Trout electrofishing CPUE exceeds 

2. Provide a quality trout fishing experience w

frequency commensurate with the Blue Ristatus of the fishery 

1. Angler catch rate 

≥ 1 Rainbow Trout per hour 

3. Grow quality sized trout that are available 

angler, consistent with the Blue Ribbon stafishery 

1. 10 Rainbow Trout 

≥ 14 inches caught by the a

10-hour day, at least one 

≥ 20 inches 

4. Maintain trout condition factor 

≥ 1 during 

summer months 
Photo: Geo

• Monitoring Goals 

–Representative sample of: 

• Fish susceptible to nearshore night 

electrofishing 

• Anglers 
Objectives (per year)

• Three electrofishing sampling trips 

• Spring, summer, fall 

• Angler surveys 

• six days per month (72 

per year) 

• One night sampling for rare non-natives in summe

Guide Nat Jensen recently fished with George and Aneeta from New Mexico and was rewarded with this 18" wild L(Lees Ferry Anglers 3 December 2016). 
Electrofishing 

• Reach ~ 15 mi • Divided into 250 m “sample reaches” (n=224• Three nights of sampling 

– nearshore – Two boats (Achilles – inflatable) – 36-40 samples per trip (randomly selected) 

By G. Andrejko 
Processing 

• Identification • Total length • Weight (for non-natives only)• Check sex/reproductive 

status 

• Scan for tags 

– PIT tag native fish 

By G. Andrejko
Electrofishing 

metrics

• Species composition 

–Rainbow trout 

• CPUE • Relative fish condition (Kn) • Fall: percent juveniles and 

fall juvenile CPUE 

http://fishbio.com/wp‐content/uploads/2010/
Rainbow Trout catch per unit ef

Rainbow trout CPUE (fish/min)
 

10

86420 

(fish/min) 

1991 1994 1997 2000 2003 2006 2009 2012 

Year 
Juvenile (<152 mm total length) Rainbow 

the fall (% of RBT catch)

Fraction of young of the year Rainbow Trout

captured in the fall 

0.00 0.20 0.40 0.60 0.80 1.00 

1990 1995 2000 2005 2010 

Year
Fall juvenile (<152 mm) Rainb

Trout CPUE (fish/minute)

Fall juvenile Rainbow Trout CPUE (fish/min) 0 2 4 6 8 10 12 14 16 

2000 2002 2004 2006 2008 2010 2012 2014 

Year
Frequency 

Rainbow Trout length frequen

histograms by year

600 400 200 

0 

600 400 200 

0 

600 400 200 

0 

600 400 200 

0 

600 400 200 

0 

100 200 300 400 500 600 100 200 300 400 500 600 100 200 300 400 500 600 100 200 300 400 500 600 

Total length (mm) 

1991 1992 1993 1996 1998 1999 2000 2001 2003 2004 2005 2006 2008 2009 2010 2011 2013 2014 2015 2016 10
1/1/1990 1/1/1992 1/1/1994 1/1/1996 1/1/1998 1/1/2000 1/1/2002 1/1/2004 1/1/2006 1/1/20

1.4 Rainbow Trout 

relative condition 

1.2 1.0 

(Kn) by size class 0.8

Rainbow trout fish condition (Kn) 

1.41.2 1.0 0.8 1.4 1.2 1.0 0.8 0.6 0.4 

152 - 305 mm 

306 - 405 mm 

 > 405 mm 

Photo by Skip Dixon, Lees Ferry Anglers 18 Sept 2016 Date 
Log(relative fish condition (Kn))
 

Rainbow Trout condition (Kn) 

relative abundance (CPUE fish/m

0.6 0.4 Sub0.2 0.0

-0.2-0.4-0.6-0.8-1.0

Ad

0.80 0.85 0.90 0.95 1.00 1.05 1.10 

Catch per unit effort (fish/minute) 
Angler surveys 

• CPUE (boat and walk-in)• Angler use (anglers/year)

– Game camera – providing supplemental 

data on use (2015-2016) 

• Angler satisfaction • Harvest 
Angler CPUE (fish/hour) 

0.00 0.25 0.50 0.75 1.00 1.25 1.50 1.75 2.00 2.25 2.50 

Boat angler CPUE Walk-in angler CPUE 

Angler CPUE (fish/hour) 

1975 1980 1985 1990 1995 2000 2005 2010 

Year
Angler Satisfaction rating (1

Average yearly angler satisfaction 

0 1 2 3 4 5 6 

boat walk-in 

R

2=0.87, p= 0.0138 

2011 2012 2013 2014 2015 

Year
Rainbow trout CPUE (fish/minute)

 standard electrofishing 

0 2 4 6 8 

10 

Electrofishing Boat anglers Shoreline anglers 

1992 1995 1998 2001 2004 2007 2010 2013 

Year 
Relative angler use by yea

0 

2000 4000 6000 8000 

10000 12000 14000 

BOAT ANGLERS WALK-IN ANGLE

Number of anglers 

2000 2002 2004 2006 2008 2010 2012 2014 

Year
Brown Trout 

• Emerging concern 

https://www.pinterest.com/pin/544430236/ Lees Ferry Anglers
0.10

Brown Trout average electrofishing 

Average yearly CPUE (fish/minute)
 0.08 0.06 0.04 0.02

0.00

(fish/minute) 

2000 2002 2004 2006 2008 2010 2012 20

Year 
Number 

Brown Trout length frequenc

histograms

1996 1999 2000 2001 

1510

50 

2004 2005 2006 2007 

1510

50 

2010 2011 2012 2013 

1510

50

100 200 300 400 500 600 100 200 300 400 500 600 

2015 2016

1510

50

100 200 300 400 500 600 100 200 300 400 500 600

Total length (mm)
Brown Trout fall length freque

2000 2001 2003 2008 2012 2013 2015 2016 

0 5 

10 15 

0 5 

10 15 

0 5 

10 15 

Density 

histograms 

100 200 300 400 500 600 100 200 300 400 500 600

Total length (mm)
Brown Trout avg. electrofishing CPUE (fish

Brown Trout CPUE (fish/hour)
 8

6420

Lees Ferry Reach 4 (RM 109-180) 

2000 2002 2004 2006 2008 2010 2012 2014 

Year
Fisheries Management Plan 

Colorado River-Lees Ferry (AGFD 

“Other trout species are not desirable in thand will not be purposefully managed thereTrout are know predators of native fish and removed during regular fisheries monitorinAnglers will be encouraged to remove Browwhen they are caught.” 
New monitoring aspects

• Move forward on citizen 

science project utilizing fishing guides to measure fish they capture 

• Use Osprey aluminum 

boat 

• Potentially add a markrecapture component

Photo: Lees FerNatalie Jensen 
Acknowledgements 

Humphrey Summit & Saint Judes - boatmen All of the volunteers Past & present agency personnel Steve Harding Lees Ferry Anglers for images use
Future 

• Add mark-recapture component

– Lees Ferry reach is the sample area (RM -1

– Tag only Rainbow Trout above 150 mm TL– Tag only a percentage of Rainbow Trout ca

(30%) or 1000? 

– Results 

Year RBT >= 150

mm

• No population estimate • Survival? (biased) 

• Growth • Movement 

2011 167

2012 288

2013 304

2014 343

2015 163

2016 48