LONG-TERM 

MONITORING OF THE LEES FERRY FISHERY: UPDATE 

AMWG – January 27, 2016 

Lisa Winters, Bill Stewart, Dave Rogowski, Robin Osterhoudt, Pilar W
Goal 

• To maintain a quality rainbow trout fishery in Glen 

Photo: 
NPS Comprehensive Fisheries 

Management Plan 

• Relative Abundance 

rainbow trout CPUE > 1 fish/minute (fall e-fishing)

• Recruitment 

rainbow trout < 152 mm TL make up greater than 20% of catch (fall e-fishing) 

• Angler Catch 

catch rates 

≥ 0.5 fish/ hour, with 

average size > 14” 
Angler Recommendations 

• Size structure indicative of 

rainbow trout population (Y50%) 

• Angler catch rates >1 fish/h

rainbows 

≥14” 

• Angler catch rates >0.1 fish

rainbows 

≥20” 

• Robust trout body condition 

in summer) 

• A diverse aquatic food base 

abundance of EPT species 
AGFD Fisheries Management P
Fisheries Management Plan –

Colorado River Lees Ferry 

Parameters Objective Guideline Strategies if Objectives are 

OBJECTIVE 1 - Maintain a healthy population of rainbow trout at Lees Ferry to su

fishing. 

Recruitment Abundance 

Rainbow trout 

≤ 6 inches compose 20% -  Stocking 

50% of the population (determined by fall 

 Trout management f

electrofishing) 

 HFEs 

Rainbow trout electrofishing CPUE exceeds 

 Stocking 

1 fish/minute (all sizes of trout) 

 HFEs  Change in regulation
Fisheries Management Plan –

Colorado River Lees Ferry 

Parameters Objective Guideline Strategies if Objectives are 

OBJECTIVE 1 - Maintain a healthy population of rainbow trout at Lees Ferry to su

fishing. 

Recruitment Rainbow trout 

≤ 6 inches compose 20% -

50% of the population (determined by fall electrofishing) 

 Stocking  Trout management f HFEs 

Rainbow trout electrofishing CPUE exceeds 1 fish/minute (all sizes of trout) 

 Stocking  HFEs  Change in regulation

Abundance 

OBJECTIVE 2 – Provide a quality trout fishing experience with catch frequency com

Blue Ribbon status of the fishery. 

Angler Catch Rate 

Angler catch rate 

≥ 1 rainbow trout/hour 

 Stocking  HFEs  Change in regulation
Fisheries Management Plan –

Colorado River Lees Ferry 

Parameters Objective Guideline Strategies if Objectives are 

OBJECTIVE 1 - Maintain a healthy population of rainbow trout at Lees Ferry to su

fishing. 

Recruitment Rainbow trout 

≤ 6 inches compose 20% -

50% of the population (determined by fall electrofishing) 

 Stocking  Trout management f HFEs 

Rainbow trout electrofishing CPUE exceeds 1 fish/minute (all sizes of trout) 

 Stocking  HFEs  Change in regulation

Abundance 

OBJECTIVE 2 – Provide a quality trout fishing experience with catch frequency com

Blue Ribbon status of the fishery. 

Angler Catch Rate 

Angler catch rate 

≥ 1 rainbow trout/hour 

 Stocking  HFEs  Change in regulation

OBJECTIVE 3 – Grow quality sized trout that are available to the angler, consistent w

status of the fishery. 

Angler Catch Quality 

10 rainbow trout 

≥ 14 inches caught by the 

angler in a 10-hour day; one 

≥ 20 inches 

caught by angler in 10 hour day Maintain trout condition factor 

≥ 1 during the 

summer months 

 Food base enhancem Trout management f Change in regulation
Fisheries Management Plan –

Colorado River Lees Ferry 

Parameters Objective Guideline Strategies if Objectives are 

OBJECTIVE 1 - Maintain a healthy population of rainbow trout at Lees Ferry to su

fishing. 

Recruitment Rainbow trout 

≤ 6 inches compose 20% -

50% of the population (determined by fall electrofishing) 

 Stocking  Trout management f HFEs 

Rainbow trout electrofishing CPUE exceeds 1 fish/minute (all sizes of trout) 

 Stocking  HFEs  Change in regulation

Abundance 

OBJECTIVE 2 – Provide a quality trout fishing experience with catch frequency com

Blue Ribbon status of the fishery. 

Angler Catch Rate 

Angler catch rate 

≥ 1 rainbow trout/hour 

 Stocking  HFEs  Change in regulation

OBJECTIVE 3 – Grow quality sized trout that are available to the angler, consistent w

status of the fishery. 

Angler Catch Quality 

10 rainbow trout 

≥ 14 inches caught by the 

angler in a 10-hour day; one 

≥ 20 inches 

caught by angler in 10 hour day Maintain trout condition factor 

≥ 1 during the 

summer months 

 Food base enhancem Trout management f Change in regulation

OBJECTIVE 4 – Avoid catastrophic failure of the trout population, and establish prot

recovery from population loss. 

Water Quality Dissolved oxygen 

≥ 5 mg/l as measured at 

outflow from GCD. 

 Flow manipulation  Temperature control  Use of river outlet tu

If failure of multiple age classes is documented by electrofishing and <0.25 trout/hour documented in creel surveys, mitigation will be necessary. 

 Stocking  Translocation of fish Catastrophic Failure of 

Population 
Objective 1 – Maintain a healthy 

population of rainbow trout at Lees Fto support recreational fishing 
Young of the Year (fall only) 

1.00 0.80 0.60 0.40 0.20 0.00

1990 1995 2000 2005 2010 

Year 

Fraction of young of the year rainbow trout 

captured in the fall
 
Young of the Year (fall only)
Rainbow Trout CPUE (boat)

Rainbow trout CPUE (fish/min) 

0 2 4 6 8 

10 

1991 1993 1995 1997 1999 2001 2003 2005 2007 2009 2011 2013 

Year 
Objective 2– provide a quality trout fish

experience with catch frequency commensurate with the Blue Ribbon status of the fishery. Objective 3– grow quality sized trout thare available to the angler, consistent wthe Blue Ribbon status of the fishery. 
Creel 

• 1,989 anglers interviewed 

• 1,557 upriver • 432 walk-in 

• 12,658 rainbow trout caught 

Angler 

Boaters 

Walk-in 

CPUE (f

1.0

0.2
Angler Catch Rates
Angler Catch Rates

• No accurate representation of size of fish anglers catc• Change creel question to “how many fish over 14 inch

many of those were over 20 inches?” 
Total length (mm)

F re q u e n cy

Angler Catch Rates 150 100

50 100 150 200 250 

Total Length (m

spring 

summer 

fall 

0 

50 

0 

50 

100 150 

0 

50 

100 150 

Number of Fish 

• No accurate representation of size of fish anglers catc• Change creel question to “how many fish over 14 inch

many of those were over 20 inches?” 
Condition 
Objective 4– avoid catastrophic failu

the trout population, and establish protocols for recovery from populatioloss 
Dissolved Oxygen
Year Classes

150 100 

50 

0 

150 

Frequency 100 50 

0 

150 100 

50 

0 

spring 

summer 

fall 

50 100 150 200 250 300 350 400 

Total length (mm) 
Angler Catch Rates
Fisheries Management Plan –

Colorado River Lees Ferry 

Parameters Objective Guideline 2015 Status 

OBJECTIVE 1 - Maintain a healthy population of rainbow trout at Lees Ferry to su

fishing. 

Recruitment Rainbow trout 

≤ 6 inches compose 20% -

50% of the population (determined by fall electrofishing) 

64% 

Rainbow trout electrofishing CPUE exceeds 1 fish/minute (all sizes of trout) 2.22 fis

Abundance 

OBJECTIVE 2 – Provide a quality trout fishing experience with catch frequency com

Blue Ribbon status of the fishery. 

Angler Catch Rate 

Angler catch rate 

≥ 1 rainbow trout/hour Boat = 1.06 f

Walk-in = 0.2

OBJECTIVE 3 – Grow quality sized trout that are available to the angler, consistent w

status of the fishery. 

Angler Catch Quality 

10 rainbow trout 

≥ 14 inches caught by the 

angler in a 10-hour day; one 

≥ 20 inches 

caught by angler in 10 hour day Maintain trout condition factor 

≥ 1 during the 

summer months 

0.01 fish/h

Kn = 0.99 

OBJECTIVE 4 – Avoid catastrophic failure of the trout population, and establish prot

recovery from population loss. 

Water Quality Dissolved oxygen 

≥ 5 mg/l as measured at 

outflow from GCD. 5.06 - 10.2If failure of multiple age classes is documented by electrofishing and <0.25 trout/hour documented in creel surveys, mitigation will be necessary. 

See ab

multiple age c

Catastrophic Failure of Population 
Species Composition

Species Spring March Summer July Fall October Total 

Rainbow Trout 587 895 1018 2500 

Brown Trout 8 18 27 53 

Common Carp 1 1 0 2 

Flannelmouth 

Sucker 1 0 17 18 

Walleye 0 3 0 3 
53 

Species Composition

Species Spring March Summer July Fall October Total 

Rainbow Trout 587 895 1018 

Brown Trout 8 18 27 

Common Carp 1 1 0 

Flannelmouth 

Sucker 1 0 17 18 

Walleye 0 3 0 3 

2500 

2 
Nonnative Sampling 

• One night in during July monitoring • Carp at -12 mile slough 

• Depletion sampling • 110, 48, 50 by pass • 54% recaptures • Estimated 290 [244,393] carp total in slough 

• 8 walleye, 3 flannelmouth and 43 green sunfish c
Nonnative Sampling 

• Typical July Nonnative monitoring sites: 

Night 1: Nonnative Sampling

RM Side Comments RM Side Com

‐15.78

R

R Below Spillway ‐12.05_L L Slo

‐15.78 L L Below Spillway ‐12.19_L L Slo

‐14.3 L L 14 mile Spring ‐12.35_L L Slo

‐14.0 L L Rocky Shoreline Habitat ‐12.15_LS L Slo

‐13.7

R

R Spring Inflow

‐13.5 L L Spring Inflow

‐11.0

R

R Below Ferry Swale Bar

‐10.9 L L Rocky Shoreline Habitat

‐6.9 L L Backwater Feature‐3.3 L L Warm Spring Inflow

‐1.5 L L Backwater Feature

• Other spots we are missing? • Timing of surveys? • As conditions may become better for nonnative invasi
Camera Creel 

• Better idea of the usage of the fishery • June 2015 – June 2016 • Picture every 30 seconds during daylight hours • Correspond with our 6 days per month of in perso• Novel technique 
Camera Creel

• ImageJ software • Timelapse Program 

• Mark boats when th

on the river and travupstream, mark whe

• Not counting downs

not counting CRD ra

• Creel is only 6 days 

month from 12-6pm 

• This counts those w• This counts non-ang

• Initial results show w

account for 30% moanglers in the came
Summary 

• AGFD has a Fisheries Management Plan – Color

River Lees Ferry 

• Electrofishing CPUE of rainbow trout is not as bad as we 

would be after the “crash” 

• Angler CPUE okay... 

• More brown trout than normal • Green sunfish - Is our nonnative sampling good e• Use of camera creel to better inform angler usage 
Acknowledgments 

• USGS – Grand Canyon Monitoring and Research • Fantastic volunteers • St. Jude’s Enterprises, LLC. Boatmen • Creel guru, Steve Harding