Management Prescription

Rain Trout:

Maintain and enhance a wild (selÊsustaining) Blue Ribbon Rainbow Trout fishery at Lees Ferry

that does not adversely affect the native aquatic community in Grand Canyon National park with

4 main objectives (Table 1).

Table 1. Lees Fer:ry objectives and Adaptive Management strategies:

Parameters Objective Guideline Stra if ob ectives are not met

OBTECTIVE Maintøin a healthy population ofRainbow Trout at Lees Feruy to

recreatíon øl

Recruitment

a

Rainbow Trout < 6 inches compose

20% - 50% of the Lees Ferry

population as determined by fall

electrofishing

o Stocking

o Trout Management Flows

o HFEs

Abundance Rainbow Trout electrofi shing

CPUE exceeds 1 fish per minute

(all sizes of trout)

. Stocking

o HFEs

o Change in regulations

tvitlt catclt OBTECTIVE Pro .fr"quency vide ü qunlìty troutfishing expertence

contmen surate wíth the BIue Ríbbon status the

Angler Catch

Rate

Angler catch rate > I Rainbow

Trout per hour

o Stocking

. HFEs

. Change in regulations

OBJECTIVE - Grow c1

the Blue Ríbbon stctttts

uality sízed trout that are svailøble to tlte ttngler, consistent wíth

the

. Food base enhancement

o Trout Management Flows

. Change in regulations

Angler Catch

Quality

10 Rainbow Trout > 14 inches

caught by the angler in a 1O-hour

day, at least one > 20 inches

Maintain trout condition factor > 1

the summer months

OBTECTIVE Avoid cøtastrophícføilure ofthe trout populøtion, ønd establish

/ass. 'W'ater 

Quality Dissolved Oxygen > 5 mg/l as

measured at outflow from GCD

o Flow manipulation

o Temperature Control Device

o Use of river outlet tubes

Catastrophic

Failure of

Population

If failure of multiple age classes is

documented by electrofishing and

<0.25 trout per hour is documented

in creel surveys, mitigation will be

necessary.

o Stocking

. Translocation of fish

Lees Ferry Fish Management Plan

Date: September 2015 Page 3
Lees Ferry Fisheries Update 

(preliminary data)

TWG Meeting - October 20, 2015

Photo: George Andrejko
NPS Comprehensive Fish Management 

Plan

• Low Recruitment: < 20% for 

more than three years.

• Low relative abundance: 

efishing < 1 fish/min for 2 

consecutive years.

• Low angler catch: ≤ 0.5 

fish/hour and size is < 14” for 

two consecutive years.
Angler Recommendations

• Size structure indicative of a 

stable RBT population (YOY = 

20-50% of population)

• Angler catch rate > 1 fish/hr

for RBT ≥ 14”

• Angler catch rate > 0.1 fish/hr

for RBT ≥ 20”

• A robust body condition (Kn ≥ 

1.0 in summer months)

• A diverse aquatic food base 

with 10% abundance of EPT 

species
Parameters Objective Guideline Strategies if Objectives are not met

OBJECTIVE - Maintain a healthy population of Rainbow Trout at Lees Ferry to support recreational fishing.

Recruitment Rainbow Trout ≤ 6 inches compose 20% - 50% of the 

Lees Ferry population as determined by fall 

electrofishing 

 Stocking

 Trout Management Flows

 HFEs

Abundance Rainbow Trout electrofishing CPUE exceeds 1 fish per 

minute (all sizes of trout)

 Stocking 

 HFEs

 Change in regulations

OBJECTIVE – Provide a quality trout fishing experience with catch frequency commensurate with the Blue Ribbon status of the fishery.

Angler Catch Rate Angler catch rate ≥ 1 Rainbow Trout per hour  Stocking

 HFEs

 Change in regulations

OBJECTIVE – Grow quality sized trout that are available to the angler, consistent with the Blue Ribbon status of the fishery.

Angler Catch Quality 10 Rainbow Trout ≥ 14 inches caught by the angler in a 

10-hour day, at least one ≥ 20 inches

Maintain trout condition factor ≥ 1 during the summer 

months.

 Food base enhancement 

 Trout Management Flows

 Change in regulations

OBJECTIVE – Avoid catastrophic failure of the trout population, and establish protocols for emergency recovery from population loss.

Water Quality Dissolved Oxygen ≥ 5 mg/l as measured at outflow from 

GCD.

 Flow manipulation

 Temperature Control Device

 Use of river outlet tubes

Catastrophic Failure of 

Population

If failure of multiple age classes is documented by 

electrofishing and <0.25 trout per hour is documented in 

creel surveys, mitigation will be necessary.

 Stocking

 Translocation of fish
Objective – Maintain a healthy 

population of Rainbow Tout at Lees 

Ferry to support recreational fishing.

Photo: George Andrejko
0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

200120022003200420052006200720082009201020112012201320142015

Percent Fall YOY

AZGFD goal

NPS Plan Stocking Trigger

(> 3 consecutive years)
0

2

4

6

8

10

12

14

16

2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015

YOY CPUE 

(from fall surveys)
0

1

2

3

4

5

6

7

8

9

1991199219931994199519961997199819992000200120022003200420052006200720082009201020112012201320142015

Electrofishing CPUE

AZGFD Goal

NPS Plan Stocking Trigger 

(≥2 consecutive years) 
Objective – Provide a quality trout 

fishing experience with catch 

frequency commensurate with the 

Blue Ribbon status of the fishery.

Objective – Grow quality sized trout 

that are available to the angler, 

consistent with the Blue Ribbon 

status of the fishery.

Photo: George Andrejko
0

0.25

0.5

0.75

1

1.25

1.5

1.75

2

2.25

1964196719761978198019821984198619881990199219941996199820002002200420062008201020122014

Angler Catch Rates 

Boat in Red

Shore in Pink

AZGFD Goal

NPS Plan Stocking Trigger 

(2 consecutive years)
0

0.02

0.04

0.06

0.08

0.1

0.12

0.14

2012 2013 2014 2015

Angler Catch Rates > 18”

AZGFD Goal > 20”
0.8

0.85

0.9

0.95

1

1.05

1.1

1.15

1.2

1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015

Condition 6”-12”

0.8

0.85

0.9

0.95

1

1.05

1.1

1.15

1.2

1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015

Condition 12”-16”

0.2

0.4

0.6

0.8

1

1.2

1.4

1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015

Condition > 16”

AZGFD Goal

AZGFD Goal

AZGFD Goal
Objective – Avoid catastrophic failure 

of the trout population, and establish 

protocols for recovery from population 

loss.

Photo: George Andrejko
3.6 mg/L 

(Oct 2005)

4.4 mg/L 

(Oct 2014)

DO at Dam

AZGFD Goal

USGS data
0

1

2

3

4

5

6

7

8

9

10

11

12

13

5.04 mg/L 

(October 31 2014)

5.89 mg/L 

(Sept 28, 2015)

5.69 mg/L

(Sept 28,2014)

DO at Lees 

Ferry

AZGFD Goal
0

0.25

0.5

0.75

1

1.25

1.5

1.75

2

2.25

1964196719761978198019821984198619881990199219941996199820002002200420062008201020122014

Angler Catch Rates 

Boat in Red

Shore in Pink

AZGFD Goal
0

20

40

60

80

100

120

140

160

180

30 50 70 90 110 130 150 170 190 210 230 250 270 290 310 330 350 370 390 410 430

# of RBT

TL in mm

Frequency
Current Status

Parameters Objective Guideline 2015 Status (preliminary)

OBJECTIVE - Maintain a healthy population of Rainbow Trout at Lees Ferry to support recreational fishing.

Recruitment Rainbow Trout ≤ 6 inches compose 20% - 50% of the 

Lees Ferry population as determined by fall 

electrofishing 

57%

Abundance Rainbow Trout electrofishing CPUE exceeds 1 fish per 

minute (all sizes of trout) 2.22 fish/min

OBJECTIVE – Provide a quality trout fishing experience with catch frequency commensurate with the Blue Ribbon status of the fishery.

Angler Catch Rate Angler catch rate ≥ 1 Rainbow Trout per hour Boat = 1.31 fish/hr

Walk-in = 0.18 fish/hr

OBJECTIVE – Grow quality sized trout that are available to the angler, consistent with the Blue Ribbon status of the fishery.

Angler Catch Quality 10 Rainbow Trout ≥ 14 inches caught by the angler in a 

10-hour day, at least one ≥ 20 inches

Maintain trout condition factor ≥ 1 during the summer 

months.

 0.019 fish/hr (>18”)

 Kn = 0.98-1.08

OBJECTIVE – Avoid catastrophic failure of the trout population, and establish protocols for emergency recovery from population loss.

Water Quality Dissolved Oxygen ≥ 5 mg/l as measured at outflow from 

GCD.

Likely to go below 5 mg/L at Dam 

(LF reading 5.89 on Sept 28th)

Catastrophic Failure of 

Population

If failure of multiple age classes is documented by 

electrofishing and <0.25 trout per hour is documented in 

creel surveys, mitigation will be necessary.

See above and multiple age classes 

exist.
Recommendations

• Real time DO information from GCD

• Development of a low DO action plan

• Development of food base enhancement 

strategies

• Creation of an ad hoc group to address 

strategies for reaching objectives

• If sand budget allows would support a Spring 

HFE
Questions