Climate Variability and chum salmon production and survival in the North Pacific

Suam Kim, S. Kang, H. Seo, E. Kim, and M. Kang

Pukyong National University

CCCC Paper Session Oct. 31, 2007

Relationship between climate, ocean Relationship between climate, ocean environment, and marine ecosystemsenvironment, and marine ecosystems

• increase ingreenhouse gas

• atmospheric warming

Climate change

Changes in ocean environment

Ecosystem reconstruction

• SST increase• ocean currents change•sea levels rise

• changes in distribution and

physiology • fluctuations in

production

Air temperature at Kodiak

Pink salmon catch in Alaska

Pink salmon catch in North Korea

Tele-connection!?

Chum salmon, Oncorhynchus keta

Chum salmon is one of the most abundant salmon species in the North Pacific, so that this species is economically and ecologically important.

0

200,000

400,000

600,000

800,000

1,000,000

1,200,000

1950 1960 1970 1980 1990 2000

chumpinktotal

Catches of chum salmon (thin), pink salmon (dashed), total salmons (thick) in the North Pacific, 1950~2005.

Chum salmon, Oncorhynchus keta

Chum salmon is one of the most abundant salmon species in the North Pacific, so that this species is economically and ecologically important.

Salmon enhancement program in Korea has focused on this species since mid 1980s.

Change in abundance of hatcheries and wild chum salmon in the North Pacific Ocean (Kaeriyama, 2003)

Hatchery

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WildHatchery

Mill

ions

fish

Such increases in catch might be due to better environmental conditions as well as enhancement programs of each nation.

38°N

36°N

34°N

126°E 128°E 130°E

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45

6789101112

131415

161718

1. Nam-gang (Nam river)2. Myeongpa-cheon (Myeongpa stream)3. Buk-cheon (Buk stream)4. Namdae-cheon (Namdae stream): Yangyang 5. Yeongok-cheon (Yeongok stream)6. Nakpung-cheon (Nakpung stream)7. Jusu-cheon (Jusu stream)8. Jeon-cheon (Jeon stream)9. Osip-cheon (Osip stream): Samcheok10. Maeup-cheon (Maeup stream)11. Gagok-cheon (Gagok stream)12. Wangpi-cheon (Wangpi stream)13. Namdae-cheon (Namdae stream): Uljin 14. Songcheon-cheon (Songcheon stream)15. Osip-cheon (Osip stream): Yeongdeok 16. Taehwa-gang (Taehwa river)17. Ilgwang-cheon (Ilgwang stream)18. Seomjin-gang (Seomjin river)

18 streams where fry chum salmon are released in spring in Korea

WinterSpring(12~5)

SummerFall

(6~11)

Summer?Fall

(?~11)

Okhotsk Sea

Bering Sea

North Pacific Ocean

WinterSpring(12~5)

Gulf of Alaska

SpringSummer

?

Schematic migration model of chum salmon released from Korea (modified from Urawa et al., 2000).

Chum salmon, Oncorhynchus keta

Chum salmon is one of the most abundant salmon species in the North Pacific, so that this species is economically and ecologically important.

Salmon enhancement program in Korea has focused on this species since mid 1980s.

Environmental variability might be a major forcing for determining stock condition and behavior of chum salmon.

The numbers of fry released at year i and returning adults of chum salmon at year i+3. Catch of returning adults at year i+3 was matched with fry released at year i in the graphs.

Returns/Catches were not always proportional to the number of fry released from the hatcheries!!!

Objectives:

Investigation on relationship between chum salmon biology and climate variability in the North Pacific

Methods and materials:

Climate/Ocean Indices:ALPISOIAOIPDOI

Biological parameters on chum salmon:CatchGrowthReturn rate

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1950 1960 1970 1980 1990 2000

ALP

I

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. CuS

um A

LPI

ALPICuSum

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1950 1960 1970 1980 1990 2000

SO

I

-10123456789

. CuS

um S

OI

SOICuSum

-1.5

-1

-0.5

0

0.5

1

1.5

1950 1960 1970 1980 1990 2000

AO

I

-5-4.5-4-3.5-3-2.5-2-1.5-1-0.500.5

. CuS

um A

OI

AOICuSum AOI

-2.5-2

-1.5-1

-0.50

0.51

1.52

2.5

1950 1960 1970 1980 1990 2000

PD

OI

-16

-14

-12-10

-8

-6

-4-2

0

2

. CuS

um P

DO

I

PDOICuSum PDOI

Four major climate/Ocean indices in the Pacific Ocean

Most graphs show the changes in 1976, 1988, and 1998.

Asia yield with CuSum of chum salmon, 1925-2001

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ch (1

,000

t)

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CuS

um (1,000t)

North America yield with CuSum of chum salmon, 1925-2001

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ch (1

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uSum

(1,000t)

ALPI SOI PDOI AOI

North America 0.202 -0.029 0.326

** 0.157

Asia 0.212 -0.167 0.349** 0.301*

Pacific total 0.224 -0.145 0.379

** 0.286*

Correlations between chum salmon production and Environmental Indices over the Pacific Ocean during 1950~2001

ALPI SOI PDOI AOI

North America

Asia

7531-1-3-5-7

7531-1-3-5-7

7531-1-3-5-7

7531-1-3-5-7

7531-1-3-5-7

7531-1-3-5-7

7531-1-3-5-7

7531-1-3-5-7

Result of cross-correlation function analysis between regional chum salmon catches and four environmental indices during 1950~2001

Time-lag effect

North America Asia

ALPI

SOI

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Trend of CuSum of regional chum salmon catches (thick lines) and four environmental indices (thin lines) during 1950~2001

North America Asia

PDOI

AOI

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Trend of CuSum of regional chum salmon catches (thick lines) and four environmental indices (thin lines) during 1950~2001

Conclusion I:

There was a major change in climate during the mid 1970s, and chum salmon population responded to this climate event with a time-lag.

The PDO and chum salmon returns showed a highly significant correlation with a time-lag of 3 years, while the AOI with a time-lag of 6~7 years.

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-1

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0.5

1

1.5

1950 1960 1970 1980 1990 2000

AO

I

-5-4.5-4-3.5-3-2.5-2-1.5-1-0.500.5

. CuS

um A

OI

AOICuSum AOI

-2.5-2

-1.5-1

-0.50

0.51

1.52

2.5

1950 1960 1970 1980 1990 2000

PD

OI

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-6

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0

2

. CuS

um P

DO

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PDOICuSum PDOI

Changes in 1976/1977

Changes in 1988/1989

SST information was collected from rectangular areas in the Bering Sea (52-58°N, 0-160°W) and the Okhotsk Sea (48-58°N, 145-155°E) using NCEP/NCAR Reanalysis. SSTs in Korean waters were measured at a light house near the hatchery (●).

Zooplankton data for Korean waters, the Okhotsk Sea, and the Bering Sea were extracted from 36-38°N and 128-131°E of KODC, Shuntov & Dulepova (1996), and Sugimoto & Tadokoro (1997), respectively.

rc in Korean waters

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0.25

1980 1982 1984 1986 1988 1990 1992 1994 1996

Year

Dev

iatio

ns o

f gro

wth

of j

uven

ilech

um s

alm

onage 5age 4age 3

Deviations of growth of juvenile chum salmon in coastal water including freshwater/river mouth. Growth information was derived from returning female salmon to mother stream at age-3 and age-4 during 1984-1998. The x-axis represents the year of growth.

P=0.014* (ANOVA) at age 5

P=0.001** (ANOVA) at age 4

P=0.013* (ANOVA) at age 3

SST (line) at light house in April (mean value=9.54°C) and deviations of zooplankton biomass (bar) off the east coast of Korea (mean value=98.98 mg/m3). Data were extracted from KODC.

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Dev

iatio

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f zoo

plan

kton

bi

omas

s zooplankton biomass and SST in Korean waters

SST at light house

P=0.096 (ANOVA)

P=0.001** (ANOVA)

Deviations of growth of young salmon in Okhotsk Sea. Growth information was derived from returning female salmon to mother stream at age-3 and age-4 during 1984-1998. The x-axis represents the year of growth.

r1-rc in Okhotsk Sea

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-0.15-0.1

-0.050

0.050.1

0.150.2

1980 1982 1984 1986 1988 1990 1992 1994 1996

Year

Dev

iatio

ns o

f you

ngsa

lmon

gro

wth

age 5age 3age 4

P=0.233 (ANOVA) at age 5

P=0.136 (ANOVA) at age 4

P=0.040*(ANOVA) at age 3

Deviation of SST in Okhotsk Sea during August and November (mean value=8.01°C) and zooplankton biomass in Okhotsk Sea (mean value=214.6 g/sq.m). Zooplankton and SST data were extracted from Shuntov & Dulepova (1996) and NECP/NCAR Reanalysis, respectively.

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1986 1987 1988 1991 1992 1993 1994

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Dev

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ns o

f zoo

plan

kton

D

eviation of SSTzooplankton biomass and SST in Okhotsk Sea

P=0.96 (ANOVA)

P=0.834 (ANOVA)

Deviations of immature salmon growth in open ocean at age 2 to 4. Growth information was derived from returning female salmon to mother stream at age-3, 4 and 5 during 1984-1998. The x-axis represents the year of growth.

r2-r1

-0.15-0.1

-0.050

0.050.1

0.150.2

1981 1983 1985 1987 1989 1991 1993 1995 1997

age 5age 3age 4

P=0.184 (ANOVA) at age 5P=0.009** (ANOVA) at age 4 P=0.002** (ANOVA) at age 3

r3-r2

-0.1

-0.05

0

0.05

0.1

1982 1984 1986 1988 1990 1992 1994 1996

P=0.001** (ANOVA) at age 5P=0.001** (ANOVA) at age 4

r4-r3

-0.08-0.06-0.04-0.02

00.020.040.06

1983 1985 1987 1989 1991 1993 1995 1997

P=0.007** (ANOVA) at age 5Dev

iatio

ns o

f im

mat

ure

salm

on g

row

thIn open ocean

12

12.5

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13.5

14

14.5

1980 1982 1984 1986 1988 1990 1992 1994 1996 19980

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Year-to-year variations in the mean zooplankton biomass (blue line) and SST (red line) in eastern Bering Sea from NCEP/NCAR Reanalysis andSugimoto & Tadokoro. (1997), respectively.

zooplankton biomassSS

T

zooplankton biomass and SST

In open ocean

P=0.038* (ANOVA)

P=0.999 (ANOVA)

0.50.550.6

0.650.7

0.750.8

0.850.9

1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997

Year class

Gc

0.00.20.40.60.81.01.21.41.61.8

Return rate

GcReturn rate

0.5

0.55

0.6

0.65

0.7

1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997

Year class

G1-

c

0.00.20.40.60.81.01.21.41.61.8

Return rate

G1-c

Return rate and growth during (a) fry and (b) age-0 juvenile

(a)

(b)

0.4

0.45

0.5

0.55

0.6

1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997

Year class

G2

0.0

0.5

1.0

1.5

2.0

Return rate

G2

0.3

0.35

0.4

0.45

0.5

1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997

Year class

G3

0.0

0.5

1.0

1.5

2.0

Return rate

`

Return rate and growth during (a) age-2 and (b) age-3

(a)

(b)

Growth of chum salmon seemed to link with change of zooplankton biomass.

In coastal water, growth of juvenile chum salmon was better in the 1990s than in the 1980s.

Growth conditions in the Okhotsk Sea seemed to be stable during the 1980s-1990s period.

In the Bering Sea, climate change around 1989 caused in reduction of zooplankton biomass, and consequently lower salmon growth in the early to mid 1990s.

Conclusion II:

Return rate of chum salmon seemed to linkwith growth during immature stages.

The favorable environments for fry chum salmonmight cause better growth in the coastal areas, but higher growth rate during the early life stage does not seem to be related to the improved return rate of spawning adults.

Rather, growth in immature stages in the Okhotsk Sea and the Bering Sea has a significant correlation with return rate indicating size-related mortality process.

Conclusion III:

Phys. Ocean.

Fishery Sci. Ocean Eco.

MeteorologistMeteorologist

Thanks for your attention!!Thanks for your attention!!