Predation Studies and ManagementIn the Columbia River Basin

Jim PetersenColumbia River Research LaboratoryWestern Fisheries Research CenterU.S. Geological SurveyCook, Washington

CALFED Workshop on PredationJune 22-23, 2005Tiburon, California

Predators

Dams

Major sources of juvenile salmonid mortality

Northern pikeminnow

MajorPredators

Walleye Smallmouth bass

Salmon

Outline• Predation estimation• Management tools

– Predator control– Dam passage options to minimize predation– Dam removal

• American shad issues in the Columbia• Predation beyond the river system

BritishColumbia

Montana

Wyoming

Oregon

Alberta

Washington

Idaho

UtahNevadaCalifornia

PacificOcean

Columbia River Basin

Measure of predation in John Day Reservoir, 1982-1990

• Consumption rate estimation using a meal turnover method – salmonids per predator per day

• Use of a bone key to identify prey species in gut samples

• Population estimates and size structure• Calculation of monthly “loss” = monthly per capita

predation rate x # predators x size …

Salmonids consumed (thousands)by all predators in John Day Reservoir

0

200

400

600

800

1000

April May June July August

Northern pikeminnow consumed 78% of salmonids

Rieman et al. 1990

Dam forebays andtailraces had highpredation losses

Mid-reservoir areastailraces had lowpredation losses

Model predictions

• 10-20% removal especially of larger predators would decrease loss 50%

• Assumed no compensation after removal ( reproductive, growth, consumption rate)

• Density dependence should be evaluated

Rieman and Beamesderfer 1991

Northern pikminnowmanagement program

• Began system-wide in 1990 (Columbia and lower Snake Rivers)

• Currently consists of a bounty fishery and a tribal fishery near dams.

• 2005 bounty pays $4-8 per fish > 9 inches; plus special tagged fish worth $500

• 267,000 caught in 2004; 2.4 million total removed

• Costs BPA approximately $3.1 million per year

BPA website; various publications

Northern pikminnowmanagement program -

evaluation• 9-16% annual exploitation rate• No detected compensation in growth or

fecundity• No change in diet of other predators,

especially smallmouth bass• “predation on juvenile salmon has been cut

by 25%”

BPA website; various publications

Northern pikminnowmanagement program – caveats

and questions• Predator- and prey-density effects have not

been evaluated sufficiently• Predation rates are highly variable (cv = 72-

140%) and large sample sizes will be necessary to detect changes of <100%

Predator density effects

Samples with > 1 salmonid prey

log Predator density

-1

0

1

log Y = 0.36 - 0.42 * log X

log

Pred

atio

n ra

te

0 1 2

McNary Damtailrace

1983-86

Petersen 2002

0

1

2

Columbia River Wind River Clearwater River

Before hatcheryreleaseAfter hatchery release

Pre

datio

n ra

te

Sample distance 1 25 60(km from release)Salmon released 14.4 2.3 1.1(million)

Collis et al. (1995)Shively et al. (1996)

Prey density effects

Prey density effects

McNary Dam tailrace

0 2 4 6 8 100

1

2

3

4

Juvenile salmonid density

Pre

da

tio

n r

ate

(sa

lmo

n /

d) • Type III functional

response• R2 = 46%• 1983-86• f(density, predator

size, prey size, temperature)

Petersen & DeAngelis (1992)

Outline• Predation estimation• Management tools

– Predator control– Dam passage options to minimize predation– Dam removal

• American shad issues in the Columbia• Predation beyond the river system

A Fish Bypass Systems- Turbine Screens- Collection Channel- Transport Pipe- Outfall location

Problems• Physical injury at screen• Predation at outfalls• Survival sometimes low

AcousticTelemetry

Radio Telemetry

The Studies

The Tools

• Route specific survival• Fish passage efficiency• Passage behavior• Tailrace egress

John Day Dam juvenile bypass system

Powerhouse 2

Powerhouse 1

Spillway

New screen bypass outfall

Old Screen bypass outfall

New surface bypass outfall

Predator Locations

(58 individuals)NPMSMB

(58 individuals)

(69 individuals)

April 25 to August 31N2002

Outline• Predation estimation• Management tools

– Predator control– Dam passage options to minimize predation– Dam removal

• American shad issues in the Columbia• Predation beyond the river system

Dams proposed for breachingon the lower Snake River

#

BonnevilleDam

Lower ColumbiaRiver

Lower SnakeRiver

100 km

Washington

Idaho

Oregon

Snake River

Hell’s CanyonDam

Hell’s CanyonDam

Study areaRiver miles147-172

Free-flowinglower SnakeRiver

ColumbiaRiver

Snake River

Mass of salmon consumed

Northern pikeminnow Smallmouth bass

0

1000

2000

3000

4000

5000

6000

Impounded Unimpounded0

1000

2000

Impounded Unimpounded

3000

4000

Juvenile salmon

consumed

(kg)

Change in predation mortality(northern pikeminnow and

smallmouth bass)

1 0.5

59

10

0

10

20

30

40

50

60

70

Impounded Breached Impounded Breached

Predation-related

mortality (%)

April-May June-August

Smallmouth bassJune - July

Crayfish 42% Other 9%

Non-salmonidFish 24%

Salmonids25%

ImpoundedN=852

Salmonids 4%

Free-flowingN=228

Non-salmonidFish 54%

Crayfish 26%

Other 16%

Petersen et al. 2000

Outline• Predation estimation• Management tools

– Predator control– Dam passage options to minimize predation– Dam removal

• American shad issues in the Columbia• Predation beyond the river system

American shad migrating past Bonneville Dam

Photo courtesy of Jim Seelye

American shad passage at Bonneville Dam

0

1

2

3

4

5

6

1936 1946 1956 1966 1976 1986 1996

Mill

ions

Year

Dam construction

#BonnevilleDam

ColumbiaRiver

100 km

Washington

Idaho

Oregon

SnakeRiver

Percent of adult American shad passing dams on thelower Columbia and Snake rivers in 2000

100 5322

5

<1<1

15

100

Juvenile anadromous fishes(Bonneville Dam, 1997)

0

25

50

75

100

April May June July Aug. Sept. Oct.

Americanshad

SalmonidsDailypassageindex

(% of maximum)

John Day Reservoir

River mile 238.5

9/7/94, 1200 h

John Day Reservoir

River mile 238.4

9/7/94, 2200 h

Day

Species compositionby trawl catch

Hydroacoustic surveys

American shad 100%

N = 38

American shad 97%

N = 215

Night

Juvenilefall chinooksalmon

JuvenileAmerican shad

Predators(northern pikeminnow,smallmouth bass,walleye)

Zooplankton,insects, chironomids,etc.

AdultAmerican shad

Juvenile American shad innorthern pikeminnow diet

0

0.2

0.4

0.6

0.8

1

1.2

1.4

0 2500 5000Juvenile shad passage index

• Bonneville Dam tailrace

• Aug.-Sept., 1990-91• N = 127-398

predators, 6 dates• Diet: 78% (1990)

5% (1991)

1990

1991

Petersen et al. (1994)

Pred

atio

n ra

t e ( p

rey/

d)

Potential effects of American shad in the diet ofnorthern pikeminnow in the lower Columbia River

Start size = 1044 g, Bonneville temperature, p = 0.173

1000

1100

1200

1300

1400

April May June July Aug. Sept. Oct. Nov.

40% shad, 50% fish, 10% misc

20% shad, 50% fish, 30% misc

50% fish, 50% misc

50% crust, 50% miscMass(g)

Research needs• Hypothesis 1 – Competition.

– Adult shad feed in the lower river and may be competing with outmigrating juvenile salmon.

– Juvenile shad compete with juvenile fall chinook salmon.• Hypothesis 2 – Predation supplementation

– American shad occur in NPM (completed) and SMB diet.• Hypothesis 4 – Nutrient re-distribution.

– Marine derived nutrients – see Limburg p 136• Hypothesis 3 – Disease transmission.

– American shad may be the vector for transmission of Ichthyophonus to marine herring. (?)

–

Caspian terns

Pacific hake

Gulls

Cormorants

Other predators on juvenile salmon

Emerging Tools

Use of Passive Integrated Transponder (PIT) tags anddevelopment of new antenna

systems

American Shad

American shadAlosa sapidissima

Nativerange

American shadAlosa sapidissima

Nativerange

1871

1926

19161876

1876

18911904

1876Kamchatka ?

Gut contents of northern pikeminnowDiet Categories (%)

All Diet CategoriesFish with food in gut

N = 141

Preyfish OnlyN = 42

Preyfish 25%

Crustaceans 16%

Other Invertebrates 2%

Shad 98%

Sculpin 1%Unidentified 1%

Unidentified 57%

1860 1880 1900 1920 1940 1960 1980 2000Im

poun

dmen

t len

gth

(c

umul

ativ

e km

)

0200400600800

100012001400

Impo

undm

ent v

olum

e (x

109 m

3 ; cu

mul

ativ

e)

0102030405060

Flow

(k

cfs)

100200300400500600

Year1860 1880 1900 1920 1940 1960 1980 2000

Salm

onid

s re

leas

ed

(

mill

ions

)

0

50

100

150

200

2501860 1880 1900 1920 1940 1960 1980 2000

Adul

t Am

eric

an s

had

(m

illio

ns)

0

1

2

3

4C

omm

erci

al s

alm

on la

ndin

gs

(mill

ion

kg)

0

5

10

15

20

25

Length

Volume

Fry

Fingerlings andyearlings

A

D

B

Salmon

American shad

C

Juvenile American shad

80 mm

70 mm

60 mm

50 mm

40 mm

Research needs• Hypothesis 1 – Competition.

– Adult shad feed in the lower river and may be competing with outmigrating juvenile salmon.

– Juvenile shad compete with juvenile fall chinook salmon.• Hypothesis 2 – Predation supplementation

– American shad occur in NPM (completed) and SMB diet.

• Hypothesis 4 – Nutrient re-distribution.– Marine derived nutrients – see Limburg p 136

• Hypothesis 3 – Disease transmission. – American shad may be the vector for transmission of

Ichthyophonus to marine herring. (?)–

John Day Reservoir

River mile 238.5

9/7/94, 1200 h

John Day Reservoir

River mile 238.4

9/7/94, 2200 h

Day

Hydroacoustic surveys

Night

0 2 4 6 8 10 12

0

5

10

15

20

25

30

35

400 2 4 6 8 10 12

0

5

10

15

20

25

30

35

40

Dep

th (m

)

Day Night

Fish / 10,000 m3

Juvenilefall chinooksalmon

JuvenileAmerican shad

Predators(northern pikeminnow,smallmouth bass,walleye)

Zooplankton,insects, chironomids,etc.

Juvenile American shad diet(% occurrence)

0 20 40 60 80 100 Cyclopoid Cop.Calanoid Cop.BosminaDaphniaAlonaLeptodoraSidaMoinaChydorusDipteran LarvaePelecypodaCorophiumIlyocryptus

Juvenile American shad diet(% number)

CyclopoidCalanoidBosminaDaphniaLeptodoraOther

Fishing for American shad in the Bonneville Dam tailrace

Photo courtesy of Jim Seelye

Exploitation

050

100150200250300350400450

1930 1940 1950 1960 1970 1980 1990 2000

Cat

ch (x

100

0)

Commercial Sport Columbia Sport Willamette

Bonneville Dam, Columbia River

Research needs

• Role of American shad in salmon recovery efforts– Competition at adult ladders– Competition with juvenile salmon for food or space– Indirect effects, such as supplements to predators

• Effects of shad on zooplankton community• Effects of shad in the lower Columbia River and the

estuary• Nutrient dynamics• Abundance and effects in other river systems of western

North America

Columbia River Basin Predator Removal

Collaborations

11.21.41.61.8

22.22.42.62.8

3

1 2 3 4 5

Number of reservoir areas

Salm

onid

loss

.

• Pooling data influences overall loss estimates

• Higher predation losses in dam forebaysand tailraces

Petersen (1994)