Matt Maples Fisheries Biologist Nevada Department of Wildlife – Western Region

Lower Truckee River Bioassessment SymposiumJanuary 5 & 6, 2009

Desert Research Institute

Status Report on Fish Populations in the

Truckee River Matt Maples

Fisheries BiologistNevada Department of Wildlife – Western Region

Outline

Historical perspective Present day fish

population Stocking program Description of river

zones 2008 survey results Management

objectives and strategies

Truckee River supported tremendous spawning runs of native Lahontan cutthroat trout (LCT) that lived in Pyramid Lake and Lake Tahoe.

Historical Perspective

Photo courtesy of Buck Wheeler

Historical Perspective

The LCT fishery dwindled in the early 1900s and eventually the original Pyramid Lake strain was lost around 1940

due to water diversions, passage barriers, over-harvest, habitat alteration, increased human development and

non-native species.

Present Day Fishery: Salmonids

Non-native rainbow and brown trout now dominate the salmonid population in the Truckee River and provide a significant recreational fishery.

LCT presence in the Truckee River is maintained by an annual stocking program.

Mountain whitefish (native) are typically found in moderate to high densities upstream of Vista Blvd.

Present Day Fishery: SalmonidsTruckee River - 2008

Percent Composition of all Salmonids Zones 2, 3, 4 and 5

Brown trout28.54%

Rainbow trout34.27%

Lahontan cutthroat trout

0.20%

Mountain whitefish36.98%

Present Day Fishery: Native, Non-Salmonids

Native, non-salmonid species persist in the Truckee River and their individual contribution to the

fishery varies by reach and habitat type.Truckee River - 2008

Percent Composition of Native, Non-Salmonids Zone: 2, 3, 4 and 5

0%

10%

20%

30%

40%

50%

60%

70%

Zone 2 Zone 3 Zone 4 Zone 5

Per

cen

t C

om

po

siti

on

Paiute sculpin

Lahontan redside shiner

Speckled dace

Mountain sucker

Tahoe sucker

Present Day Fishery: Non-Native, Non-Salmonid

Many non-native, non-salmonids have been inadvertently introduced into the Truckee River, their impact on the fishery appears to be minimal, but we have little data to confirm this hypothesis.

Species include: Green sunfish Largemouth bass Fathead minnow Mosquito fish Common carp

http://www.uaex.edu/wneal/pond_management/images/greensunfish.jpg

Present Day Fishery: Species Composition

Truckee River - 2008 Percent Composition by Category

Zones 2, 3, 4 and 5

Non-native, Non-Salmonids

1.0% Native Salmonids17.9%

Non-native Salmonids

30.2%

Native Non-Salmonids

51.0%

Stocking Program

Species Number Average Size

Lahontan cutthroat trout 21,336.00 8.11

Rainbow trout 34,184.00 9.81

Total Trout 55,520.00

Truckee River

Stocking Program - 2008

Trout are stocked between March and October – dependent on flows and water temperature.

LCT are stocked throughout the Nevada portion of the Truckee River.

All rainbow trout are triploid and are only stocked upstream of the East McCarran Bridge.

Stocking Program: HistoryTruckee River Stocking History

All Catchable Trout (greater than 6")1995 - 2007

0

15,000

30,000

45,000

60,000

75,000

1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007

Year

Nu

mb

er

of

Tro

ut

RBT

LCT

BRN

LCT have been stocked in the Truckee River for many years.

Most recent “peak” in stocking numbers reflects renewed interest in LCT Recovery and the MOA with PLPT.

River Zones

For management purposes, the Truckee River is divided into eight zones, which span from Pyramid Lake to Tahoe Dam.

Four of these zones are actively managed by the Nevada Department of Wildlife.

Zone 2: Wadsworth to Derby Dam

Zone 3: Derby Dam to E. McCarran Bridge

Zone 4: E McCarran to Mayberry Bridge

Zone 5: Mayberry Bridge to State Line

Zone Divisions

Fall 2008 – Electrofishing Survey

NDOW completed nine transects along the Truckee River, from Painted Rock to Verdi Power Dam.

Fall 2008 – Electrofishing Survey

We use a tote-barge that is equipped with a generator powered electrofishing unit.

All fish were counted, measured, weighed and released back into the river.

Fall 2008 – Electrofishing Survey

Zone 2

Truckee River - 2008 Length Frequency: Brown trout

Zone 2

0

1

2

3

4

5

6

7

8

9

10

2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28

Size Class

Nu

mb

erZone 2 Results: Brown trout

N = 6

16.7 fish/mile

Truckee River - 2008 Length Frequency: Rainbow trout

Zone 2

0

5

10

15

20

25

2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28

Size Class

Nu

mb

er

Zone 2 Results: Rainbow trout

N = 65

152 fish/mile

Zone 2 Results: Species Diversity

333 Fish Captured

10 Species

3 Undesirables

Truckee River - 2008 Percent Composition of All Species

Zone 2

Mountain sucker10.51%

Tahoe sucker12.91%

Rainbow trout19.52%

Lahontan redside shiner

49.55%

Mountain whitefish2.40%

Lahontan cutthroat trout

0.30%

Green sunfish0.30%

Largemouth bass0.30%

Brown trout1.80%

Fathead minnow2.40%

Zone 3

Truckee River - 2008 Length Frequency: Brown trout

Zone 3

0

1

2

3

4

5

6

7

8

9

10

2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28

Size Class

Nu

mb

er

Zone 3 Results: Brown trout

N = 1

6 fish/mile

Truckee River - 2008 Length Frequency: Rainbow trout

Zone 3

0

1

2

3

4

5

6

7

8

9

10

2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28

Size Class

Nu

mb

er

Zone 3 Results: Rainbow trout

N = 9

50 fish/mile

Zone 3 Results: Species Diversity

120 Fish Captured

4 Species

0 Undesirables

Truckee River - 2008 Percent Composition of All Species

Zone 3

Brown trout0.83%

Lahontan redside shiner

73.33%

Rainbow trout7.50%

Tahoe sucker18.33%

Zone 4

Truckee River - 2008 Length Frequency: Brown trout

Zone 4

0

10

20

30

40

50

60

70

80

2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28

Size Class

Nu

mb

erZone 4 Results: Brown trout

N = 157

312 fish/mile

Truckee River - 2008 Length Frequency: Rainbow trout

Zone 4

0

10

20

30

40

50

60

70

80

2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28

Size Class

Nu

mb

er

Zone 4 Results: Rainbow trout

N = 148

333 fish/mile

Zone 4 Results: Species Diversity

966 Fish Captured

9 Species

1 Undesirable

Truckee River - 2008 Percent Composition of All Species

Zone 4

Mountain sucker13.87%

Tahoe sucker15.53%

Rainbow trout15.32%

Speckled dace4.45%

Lahontan redside shiner

25.05%

Mountain whitefish8.28%

Lahontan cutthroat trout

0.10%

Green sunfish1.14% Brown trout

16.25%

Zone 5

Truckee River - 2008 Length Frequency: Brown trout

Zone 5

0

10

20

30

40

50

60

70

80

2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28

Size Class

Nu

mb

er

Zone 5 Results: Brown trout

N = 120

354 fish/mile

Truckee River - 2008 Length Frequency: Rainbow trout

Zone 5

0

10

20

30

40

50

60

70

80

2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28

Size Class

Nu

mb

er

Zone 5 Results: Rainbow trout

N = 119

315 fish/mile

Zone 5 Results: Species Diversity

653 Fish Captured

8 Species

0 Undesirables

Truckee River - 2008 Percent Composition of All Species

Zone 5

Mountain sucker12.40%

Tahoe sucker0.77%

Rainbow trout18.22%

Speckled dace0.15%

Lahontan redside shiner0.31%

Mountain whitefish42.88%

Paiute sculpin6.89%

Lahontan cutthroat trout

0.00%

Brown trout18.38%

Mountain Whitefish

Typically present in good densities upstream of Rock Park.

In 2008, we documented whitefish below Derby Dam in the Spring and Fall.

Result of increased downstream flows and adequate summer temperatures.

Photo Credit: Doug Ouellette

Truckee River - 2008 Length Frequency: Mountain whitefish

(Zones 2, 3, 4 and 5)

0

10

20

30

40

50

60

70

80

90

100

2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28

Size Class

Nu

mb

er

Mountain Whitefish

N = 360

408 fish/mile

Wild Trout Populations

Young rainbow and brown trout were found in low densities at Zone 2 and 3, but were found in moderate to high densities in Zone 4 and 5.

Photo Credit: Doug Ouellette

Wild Rainbow Trout

Truckee River 2000 - 2008 Wild Rainbow Trout

0%

20%

40%

60%

80%

100%

2000 2001 2002 2003 2004 2005 2006 2007 2008

Year

Pe

rce

nt

Cla

ss

ifie

d a

s

"Wild

"

Fishery Restoration: Lahontan cutthroat trout

In October 2002, NDOW and the Pyramid Lake Paiute Tribe signed a MOA and agreed to work toward restoration of LCT in the Truckee River.

Objectives: Reestablish a natural run of LCT up the Truckee River Utilize LCT to maintain the recreational fishery in

the Truckee River

Strategies De-emphasize stocking non-native salmonids where

feasible Utilize triploid rainbows in high angler-use areas Stock LCT fry in the upper reaches and tributaries of

the river Ongoing monitoring to assess effectiveness of various

management strategies

Fishery Restoration: Lahontan cutthroat trout

Ongoing Activities Pursue opportunities to

utilize streamside incubators in the upper river (Verdi area).

Continue to encourage habitat improvement and restoration of the lower Truckee River.

Continue to work with USCOE and support the assessment and removal of fish passage barriers on the Truckee River.

Fishery Restoration: Lahontan cutthroat trout