NON-NATIVE SALMOINDS IN LAKE SUPERIOR

Don Schreiner, MNDNR

Steve Schram, WIDNR

Shawn Sitar, MIDNR

Mike Petzold, OMNR

History

• First successful introductions began in late 1800’s with rainbow and brown trout

• Coho and chinook salmon first introduced by MI in mid 1960’s, quickly followed by other agencies

• Introductions targeted at controlling exotic invaders and redirecting angling effort

• All species have become naturalized and are sustained largely by natural reproduction

Fish Community ObjectiveNon-native Salmonids

• Manage populations of Pacific salmon, rainbow

trout and brown trout that are predominately

self-sustaining, but that may be supplemented by

stocking that is compatible with restoration and

management goals established for native fish

species.

Role on Non-native Salmonids in the Lake Superior Fish Community

• Species are migratory - spawn in streams and migrate to the lake after smolting

• Thermal habitat is limited

• Impact on a lake-wide basis is minimal

• May have significant impact in tributaries and near-shore areas

Waters of Lake Superior0-240 ft (0-80 meters)> 240 ft (> 80 meters)

The Fishery

• Approximately 1/3 of total angler catch

• Expanded sport fishing opportunities

• Provided increased shore and stream opportunity

• Created a surface water trolling fishery

• Contaminant levels less than lake trout

Status – Open Water Creel Surveys

• Wisconsin – 1972 – 2000, May 1 – Sept. 30

• Minnesota – 1972 – 2000, Memorial W.E. – Sept. 30

• Michigan – 1987 – 2000, Selected sites May 1 – Sept. 30

• Ontario – Intermittent - selected sites - diaries

• Lack of standardization in other recreational fisheries

– Spring and fall stream fisheries

– Winter fishery

Distribution of Major Salmonids in U.S. Waters of Lake Superior from

1990-2000

Lake Trout67%

Coho Salmon17%

Chinook Salmon

8%

Brown Trout2%

Rainbow Trout1%

Siscowet5%

Distribution of Major Non-native Salmonids in U.S. Waters of Lake

Superior from 1990-2000

Chinook Salmon

28% Coho Salmon61%

Rainbow Trout3%

Splake2%Brown Trout

6%

Distribution of Major Salmonids in Ontario Waters of Lake Superior 1987-1999

Chinook Salmon

13%

Brook Trout0.45%

Rainbow Trout

4%

Coho Salmon

4%

Lake Trout79%

Distribution of Major Non-native Salmonids in Ontario Waters of Lake Superior

1987-1999

Chinook Salmon

73%

Rainbow Trout16%

Coho Salmon11%

Status

• Stocking history

• Catch history

• CPUE in open water recreational fishery

Rainbow Trout

• Introduced in 1895

• Present population largely a result of natural reproduction

• Return rate of stocked yearlings less than 1% except Kamloops

• Increased control of angler exploitation

• Abundance has declined since the 1950’s – lake trout, pacific salmon, increased exploitation, stream habitat

Number of Rainbow Trout Stocked in Lake Superior

0

100

200

300

400

500

600

1970

1972

1974

1976

1978

1980

1982

1984

1986

1988

1990

1992

1994

1996

1998

2000

Year

No.

Sto

cked

(x

1000

)

Minnesota Michigan Wisconsin Ontario

Number of Rainbow Trout Caught in U.S. Waters of Lake Superior

0

2,000

4,000

6,000

8,000

10,00019

72

1974

1976

1978

1980

1982

1984

1986

1988

1990

1992

1994

1996

1998

2000

Year

Num

ber

Cau

ght

Minnesota Wisconsin Michigan

CPUE of Rainbow Trout in Lake Superior

0.00

0.01

0.02

0.03

0.04

0.0519

72

1974

1976

1978

1980

1982

1984

1986

1988

1990

1992

1994

1996

1998

2000

Year

CP

UE

Minnesota Wisconsin Michigan Ontario

Brown Trout

• Introduced in late 1890’s

• Have naturalized in a number of tributaries

• WI and MI still stock in localized areas

• Hatchery contribution 50% in WI and 40% in MI

• Brule River supports largest naturalized run

Number of Brown Trout Stocked in Lake Superior

0

100

200

300

40019

70

1972

1974

1976

1978

1980

1982

1984

1986

1988

1990

1992

1994

1996

1998

2000

Year

No.

Sto

cked

(x

1000

)

Minnesota Wisconsin Michigan

Number of Brown Trout Caught in U.S. Waters of Lake Superior

0

1,000

2,000

3,000

4,000

5,000

6,00019

72

1974

1976

1978

1980

1982

1984

1986

1988

1990

1992

1994

1996

1998

2000

Year

Num

ber

Cau

ght

Minnesota Wisconsin Michigan

CPUE of Brown Trout in U.S. Waters of Lake Superior

0

0.01

0.02

0.03

0.04

0.0519

72

1974

1976

1978

1980

1982

1984

1986

1988

1990

1992

1994

1996

1998

2000

Year

CP

UE

Minnesota Wisconsin Michigan

Coho Salmon

• Introduced by MI in 1966, MN from 1969-1974

• Quickly became naturalized, no longer stocked

• Life cycle of 3 years, anglers mostly exploit age 2+

• Harvest fluctuates greatly – fishing mostly one YC

• Slower growth and smaller size than other Great Lakes

Number of Coho Salmon Stocked in Lake Superior

0100200300400500600700

1970

1973

1976

1979

1982

1985

1988

1991

1994

1997

2000

Year

No.

Sto

cked

(x

1000

)

Minnesota Michigan

Number of Coho Salmon Caught in U.S. Waters of Lake Superior

05,000

10,00015,00020,00025,00030,00035,00040,000

1972

1974

1976

1978

1980

1982

1984

1986

1988

1990

1992

1994

1996

1998

2000

Year

Num

ber

Cau

ght

Minnesota Wisconsin Michigan

CPUE of Coho Salmon in Lake Superior

0.000.02

0.040.060.080.10

0.120.14

1972

1974

1976

1978

1980

1982

1984

1986

1988

1990

1992

1994

1996

1998

2000

Year

CP

UE

Minnesota Wisconsin Michigan Ontario

Chinook Salmon

• Introduced by MI in 1967, followed by other agencies

• Use larger rivers for spawning

• BKD relatively low compared to other Great Lakes

• Approximately 75% of chinook salmon are produced by natural reproduction – Peck et al 1999

• All agencies continue to stock – effectiveness ?????

Number of Chinook Salmon Stocked in Lake Superior

0

500

1,000

1,500

2,00019

70

1972

1974

1976

1978

1980

1982

1984

1986

1988

1990

1992

1994

1996

1998

2000

Year

No.

Sto

cked

(x

1000

)

Minnesota Wisconsin Michigan Ontario

Number of Chinook Salmon Caught in U.S. Waters of Lake Superior

0

2,000

4,000

6,000

8,000

10,000

12,00019

72

1974

1976

1978

1980

1982

1984

1986

1988

1990

1992

1994

1996

1998

2000

Year

Num

ber

Cau

ght

Minnesota Wisconsin Michigan

CPUE of Chinook Salmon in Lake Superior

0

0.01

0.02

0.03

0.04

0.0519

72

1974

1976

1978

1980

1982

1984

1986

1988

1990

1992

1994

1996

1998

2000

Year

CP

UE

Minnesota Wisconsin Michigan Ontario

Chinook Salmon Study

• Contribution of hatchery fish to fishery

• Agency specific fin clips 1988-1990

• Returns assessed from 1990-1994

• Wild fish comprised 75% lake-wide

• Hatchery contribution greatest MN-WI-MI-ON

• Significant movement

Hatchery Contributions of Chinook Salmon 1990-1994

0102030

405060

Minnesota Wisconsin Michigan Ontario

State

Per

cen

t C

ontr

ibu

tion

Minnesota Wisconsin Michigan Ontario

Pink Salmon

• Accidentally introduced in 1956

• Have become naturalized

• Life cycle of 2 years initially, 3 year life cycle common

• Harvest fluctuates greatly – one year class

• Late fall boat fishery and fall stream fishery

Number of Pink Salmon Caught in U.S. Waters of Lake Superior

0

200

400

600

800

1,000

1,20019

85

1986

1987

1988

1989

1990

1991

1992

1993

1994

1995

1996

1997

1998

1999

2000

Year

Num

ber

Cau

ght

Minnesota Michigan

Mean Size of Non-native Salmonids in U.S. Waters of Lake Superior

0.00

0.501.00

1.50

2.002.50

3.00

3.504.00

4.50

ChinookSalmon

RainbowTrout

BrownTrout

Splake CohoSalmon

PinkSalmon

Mea

n Si

ze (

lbs/

fish

)

Mean Size of Non-native Salmonids Among States of U.S. Waters of Lake Superior

0

1

2

3

4

5

6

7

ChinookSalmon

BrownTrout

CohoSalmon

RainbowTrout

PinkSalmon

Splake

Mea

n Si

ze (l

bs/fi

sh)

Minnesota Wisconsin Michigan

Recommendations

• Meeting FCO’s based on present knowledge

• Determine impact on native species in tributaries and near-shore areas

• Standardized creel surveys

• Critically review present stocking programs – Use of Lake Superior strains – Effectiveness – Cost:Benefit– Realistic expectations– Disease