Marine Survival of Klamath River Coho

Salmon

CramerFish Sciences

Funded byUS Bureau of Reclamation

Thomas Nickelson

Purpose• Gain a better understanding of the

interannual variation in marine survival of Klamath Basin coho salmon

Approach• Reconstruct an index of marine survival of

Klamath Basin Coho

• Compare survival of coho released from Iron Gate and Trinity hatcheries

• Compare survival trends of Klamath coho with trends in survival of coho from Oregon

• Compare trends in survival of Klamath coho with trends in ocean conditions

Methods• Analyze releases of CWT coho

salmon from Klamath, Trinity, and Rogue River hatcheries.

• Analyze release and return data where CWT data are not available.

• Compare survival rates among hatcheries, OPI, and with ocean conditions.

•Reconstruct an index of marine survival of Klamath Basin Coho

Iron Gate coho survival

0%

1%

2%

3%

4%

5%

6%

1976 1978 1980 1982 1984 1986 1988 1990 1992 1994 1996 1998 2000 2002

Brood year

Ind

ex

of

su

rviv

al

Conclusion• There is considerable interannual

variation in marine survival of coho salmon from the Klamath Basin

•Compare survival of coho released from Iron Gate and Trinity hatcheries

IGH and TRH coho survival

0%

1%

2%

3%

4%

5%

6%

1975 1977 1979 1981 1983 1985 1987 1989 1991 1993 1995 1997 1999 2001 2003

Brood year

Ind

ex

of

su

rviv

al

IGH Fisheries TRH Fisheries IGH Return TRH Return

IGH and TRH coho survival

y = 0.7992x - 0.0011

R2 = 0.5562

y = 1.0827x + 0.0078

R2 = 0.6929

y = 0.4172x + 0.0045

R2 = 0.693

0%

1%

2%

3%

4%

5%

6%

0% 1% 2% 3% 4%

IGH survival index

TR

H s

urv

ival

ind

ex

1994-00 Br. Escapement 1977-89 Br Fisheries 1994-00 Br. Hatchery Returns

Conclusions• Interannual variation in marine

survival of coho salmon from the mainstem Klamath and the Trinity is correlated.

• Return rates to IGH probably underestimate marine survival because returning adults stray.

•Compare survival trends of Klamath coho with trends in survival of coho from Oregon

IGH vs. Oregon coho survival

0%

1%

2%

3%

4%

5%

6%

7%

8%

1976 1978 1980 1982 1984 1986 1988 1990 1992 1994 1996 1998 2000 2002

Brood year

Ind

ex

of

su

rviv

al

CRH Total IGH Total OPI

IGH vs. CRH coho survivaly = 0.8873x + 0.0096

R2 = 0.5356

y = 0.5123x + 0.0003

R2 = 0.3272

0%

1%

2%

3%

4%

5%

6%

7%

0% 1% 2% 3% 4% 5% 6% 7% 8%

CRH survival

IGH

su

rviv

al

1977-90 Broods 1991-01 Broods

IGH vs. CRH

-

1.0

2.0

3.0

4.0

5.0

6.0

7.0

1975 1977 1979 1981 1983 1985 1987 1989 1991 1993 1995 1997 1999 2001 2003

Brood year

Rat

io o

f su

rviv

al r

ates

IGH/CRH Fisheries IGH/CRH Return

IGH vs. OPI coho survival

y = 0.4914x + 0.0139

R2 = 0.2166

y = 0.2219x + 0.0147

R2 = 0.0569

0%

1%

2%

3%

4%

5%

6%

0% 1% 2% 3% 4% 5% 6% 7% 8%

OPI survival

IGH

su

rviv

al

1977-90 Broods 1991-01 Broods

Conclusions• Interannual variation in marine survival of

coho salmon from the Klamath and the Rogue rivers is correlated.

• Survival of coho salmon from IGH appears to be higher that that for coho from CRH.

• Correlations between survival of coho salmon from IGH and survival of OPI coho are poor.

•Compare trends in survival of Klamath coho with trends in ocean conditions

Iron Gate coho survivaly = 5E-05x - 0.0151

R2 = 0.368

y = -5E-06x + 0.0244

R2 = 0.00970%

1%

2%

3%

4%

5%

6%

400 600 800 1000 1200 1400 1600 1800

Mar-Sep upwelling volume @ 39N

IGH

su

rviv

al

1977-90 Broods 1991-01 Broods

Iron Gate coho survival

y = -0.0004x + 0.0699

R2 = 0.3746

y = -0.0002x + 0.044

R2 = 0.3204

0%

1%

2%

3%

4%

5%

6%

40 60 80 100 120 140 160 180

JD of spring upwelling transition

IGH

su

rviv

al

1977-90 Broods 1991-01 Broods

IGH coho survival- p values    Cole Rivers OPI Upwelling volume JD of upwelling

Brood years Group Survival Survival Mar.-Sept. @ 39N transition @ 42-48N

           

1977-2001 Iron Gate 0.035 0.032 0.381 0.005

1977-2001 Cole Rivers   0.296 0.016 0.050

1977-2001 OPI     0.956 0.000

         

1977-1990 Iron Gate 0.007 0.127 0.037 0.048

1977-1990 Cole Rivers   0.562 0.038 0.075

1977-1990 OPI     0.726 0.000

           

1991-2001 Iron Gate 0.066 0.480 0.773 0.069

1991-2001 Cole Rivers   0.130 0.593 0.048

1991-2001 OPI     0.044 0.044

Conclusions• Interannual variation in marine survival of

coho salmon from the Klamath is correlated with indices of ocean condition.

• The relationships between survival of Klamath coho and ocean conditions have changed through time.

• Other factors such as ocean temperature probably influence survival of Klamath coho.