Regime Shifts

Anne B. HollowedSenior Scientist

Alaska Fisheries Science Center

2

Definitions (Overland et al. 2008)

• Displacement—Inspection of a time series —Statistical difference in mean given observed variance

• Mechanism—Identification of underlying processes (discrete states)—Non-linear/deterministic

• External—Systematic changes in ecosystems—Climatic or human—Changes in state = phase transitions

3

Climate Indices (Bond & Overland)

4

Mantua et al. 1997

5

1972-76

1977-81

SSTSLP

Bond et al. 2004

99-02

72-76

77-81

2003

6

Mechanistic conceptual framework (Emanuele DiLorenzo, PICES)DiLorenzo et al. 2008 GEOPHYSICAL RESEARCH LETTERS, VOL. 35

Also see Wooster and Hollowed 1995 CJFAS

7

Mechanisms: Dominant modes of North Pacific decadal variability (Emanuele DiLorenzo, 2008 &PICES presentation)

SST – Sea Surface Temperature anomaly, SSSa – Sea Surface Salinity anomaly, SSHa Sea Surface Height anomaly

8

-6-4-202468

1950

1954

1958

1962

1966

1970

1974

1978

1982

1986

1990

1994

1998

2002

Aleutian Low

Jan-

50

Jan-

55

Jan-

60

Jan-

65

Jan-

70

Jan-

75

Jan-

80

Jan-

85

Jan-

90

Jan-

95

Jan-

00

58N, 170W

54N,162W

56N, 138W

44N, 126W

32N, 120W -2 .50-2.00-1.50-1.00-0.500.000.501.001.502.002.50

Date

Lo

cati

on

Temperature Anomalies 1958 -1999

-2.50--2.00 -2.00--1.50 -1.50--1.00 -1.00--0.50 -0.50-0.00

0.00-0.50 0.50-1.00 1.00-1.50 1.50-2.00 2.00-2.50

Nino-NorthHollowed et al 2001

9

1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000

-3

-2

-1

0

1

2

3Pacific Decadal Oscillation Index, Winter (DJF), 1901-2006

1977

1946

p = 0.1l = 15h = 1

AR1 = 0.21 (IP4, m = 9)

1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000

-3

-2

-1

0

1

2

3Pacific Decadal Oscillation Index, Winter (DJF), 1901-2006

2003

1989

1977

1962

1958

1949

1943

1935

p = 0.3l = 10h = 1

Displacement

Statistically significant shifts in means relativeto within-regime variance

(Rodionov 2004)

Depends on falsepositive parameter p, and time scale l

10

Systematic Changes in Ecosystems

• Rapid shift in species composition and/or abundance

• Rapid shift in dominance (scramble competition, Rice 2001)• Shift in carrying capacity• Shift in productivity• Shift in interaction strengthIs this necessary for species co-existence? Competition,

predation, environmental disturbance (Chesson2000)

11

Mechanisms

See Bakun 2010 J. Mar. Systems 79 361-

373 for review

Concepts of Biology

Carrying capacityLogistic growthLength – weightSpecies-areaDiversity and Latitude

Key factors

CompetitionDensity dependencePrey productionEnvironmental disturbancePredation – thermal tolerances – stability

Match-mis-match Cushing (1971, 1975, 1990)Connectivity – Member vagrant Sinclair (1988)

School trap (Bakun 2001)

Loopholes (Bakun and Broad 2003)

Ocean Triads- Bakun (1996)

Enrichment

ConcentrationRetention

12

20042003200220012000199919981997199619951994199319921991199019891988198719861985198419831982198119801979197819771976197519741973197219711970Year

1995BSPelagic Trawl Duration

1990BS Bottom Trawl Duration

1990AI Bottom Trawl Duration

1993Hook and Line Effort

1982Summer Bottom Temp.

1977FHS (R/S)

1975Rock sole (R/S)

1976ATF (R/S)

1973GT (R/S)

1977Northerns (R/S)

1960POP (R/S)

1964YFS (R/S)

1975RLKI Productivity

1976TBMU Productivity

1975BLKI Productivity

1980Total crab biomass

1982BS Richness

1964Pollock (R/S)

1977Cod (R/S)

1975AK Plaice (R/S)

1982Jellyfish biomass

1982BS Diversity

1982Total CPUE

1977Atka (R/S)

1951AOI

1976COMU Productivity

1970May SST

1978Herring recruits

1901PDO

1900Total salmon catch

1916Surface Winter Air Temp.

1962AI Trophic level of catch

1954Ice Cover Index

1954BS Trophic level of catch

20042003200220012000199919981997199619951994199319921991199019891988198719861985198419831982198119801979197819771976197519741973197219711970Year

1995BSPelagic Trawl Duration

1990BS Bottom Trawl Duration

1990AI Bottom Trawl Duration

1993Hook and Line Effort

1982Summer Bottom Temp.

1977FHS (R/S)

1975Rock sole (R/S)

1976ATF (R/S)

1973GT (R/S)

1977Northerns (R/S)

1960POP (R/S)

1964YFS (R/S)

1975RLKI Productivity

1976TBMU Productivity

1975BLKI Productivity

1980Total crab biomass

1982BS Richness

1964Pollock (R/S)

1977Cod (R/S)

1975AK Plaice (R/S)

1982Jellyfish biomass

1982BS Diversity

1982Total CPUE

1977Atka (R/S)

1951AOI

1976COMU Productivity

1970May SST

1978Herring recruits

1901PDO

1900Total salmon catch

1916Surface Winter Air Temp.

1962AI Trophic level of catch

1954Ice Cover Index

1954BS Trophic level of catch

Bering Sea/Aleutian Islands

1995

2000

1990

1985

1980

1975

1970 Legend

X>2.6

2.6>X>1.6

1.6>X>0.5

0.5>X>-0.5

-0.5>X>-1.6

-1.6>X>-2.7

no data

BS Pelagic Trawl DurationBS Bottom Trawl DurationAI Bottom Trawl Duration

Hook and Line EffortSummer Bottom Temp.

FHS (R/S)Rock sole (R/S)

ATF (R/S)GT (R/S)

Northerns (R/S)POP (R/S)YFS (R/S)

RLKI ProductivityTBMU ProductivityBLKI Productivity

Total crab biomassBS RichnessPollock (R/S)

Cod (R/S)AK Plaice (R/S)

Jellyfish biomassBS Diversity

Total CPUEAtka (R/S)

AOI COMU Productivity

May SSTHerring recruits

PDOTotal salmon catch

Surf. Winter Air Temp.AI Trophic levelIce Cover Index

BS Trophic level

Bolt 2006 REFM web site.

13

Gulf of AlaskaGulf of Alaska

Climate IndicesClimate Indices

andand

ShrimpShrimp--Trawl Trawl CatchesCatches

(Biomass)(Biomass)

(Anderson and Piatt, 1999)(Anderson and Piatt, 1999)

14

POLLOCK

-0.20

-0.100.00

0.100.20

0.30

COD

-0.20

0.00

0.20

0.40

0.60

GT

-0.20

0.00

0.20

0.40

ATF

-0.20

-0.10

0.00

0.10

0.20

ROCK SOLE

-0.40

-0.20

0.00

0.20 NORTHERNS

-0.10

0.00

0.10

0.20

YFS

-0.20

0.00

0.20

0.40

1960

1966

1972

1978

1984

1990

1996

2002

FH SOLE

-0.40

-0.20

0.00

0.20

0.4019

60

1966

1972

1978

1984

1990

1996

2002

POP

-0.40

-0.20

0.00

0.20

0.40

1960

1966

1972

1978

1984

1990

1996

2002

AI ATKA

-0.10

0.00

0.10

0.20

0.30

1960

1966

1972

1978

1984

1990

1996

2002

1976/77 shift 1988/89 shift Other shift

AK PLAICE

-0.50

0.00

0.50

1.00

1960

1966

1972

1978

1984

1990

1996

2002

Bering Sea

R/S Anomalies

15

Female spawning biomass (million t)

0.0 0.2 0.4 0.6 0.8 1.0

Spa

wne

r pr

oduc

tivity

-3

-2

-1

0

1

2

3

4

1960s: Low stock, average spawner productivity

1970s: Increasing stock, high spawner productivity1980s: Decreasing stock, low spawner productivity1990s: Average stock, low spawner productivity

Regression (all years)

GOA Walleye Pollock Dorn SAFE Document AFSC REFM website

16

WC

wid

ow r

ockf

ish

BC

pin

k

EB

S h

errin

g

EB

S a

rrow

. flo

unde

r

GO

A p

ollo

ck

WC

mac

kere

l

BC

soc

keye

CA

chi

nook

WC

yel

low

tail

rock

fish

EB

S y

ello

wfin

sol

e

WC

can

ary

BC

chu

m

WC

anc

hovy

WC

hak

e

EB

S p

ollo

ck

WA

soc

keye

AI

PO

P

EB

S P

acifi

c co

d

Sitk

a he

rrin

g

GO

A P

acifi

c co

d

AI

atka

mac

kere

l

PW

S h

errin

g

WC

dov

er s

ole

WC

PO

P

WC

chi

lipep

per

GO

A P

OP

C.

AK

chu

m

WC

boc

acci

o

-0.6

-0.4

-0.2

0

0.2

0.4

C.

AK

. P

ink

BC

chi

nook

WA

chi

nook

S.

AK

soc

keye

W.

AK

chu

mG

OA

hal

ibut

S.

AK

chu

mC

. A

K c

oho

EB

S G

reen

land

tur

bot

GO

A s

able

fish

C.

AK

chi

nook

GO

A a

rrow

toot

h flo

unde

rW

A c

oho

W.

AK

chi

nook

W.

AK

coh

oE

BS

Ala

ska

plai

ceS

. A

K c

oho

C.

AK

soc

keye

S.

AK

pin

kW

C s

able

fish

OR

chi

nook

OR

coh

oW

A p

ink

W.

AK

pin

kW

A c

hum

EB

S P

OP

EB

S f

lath

ead

sole

CA

coh

o

GO

A t

horn

yhea

dB

C c

oho

S.

AK

chi

nook

W.

AK

soc

keye

EB

S r

ock

sole

0

0.2

0.4

0.6

0.8

1

Auto-correlation in recruitment (Hollowed et al. 2001)

17

Intervention Analysis (Hollowed et al. 2001)

+0.00228EBS Arrowtooth

0.91231GOA Thornyhead

0.48733GOA POP

+0.04924GOA Halibut

+0.00130GOA Arrowtooth

0.83638EBS POP

-0.01626EBS Greenland Turbot

0.79928EBS AK Plaice

DirectionP(Step77)PtsStock

18

Ho: Proportion of strong year classes is not greater

during Nino North Hollowed et al. (2001)

0.06GOA pollockPost 76

0.41EBS pollockPost 76

0.12EBS codPost 76

0.07GOA codPost 76

0.45EBS pollockAll years

0.10EBS codAll years

0.09GOA pollockAll years

0.05GOA codAll years

0.02WC HakeAll years

P valueSpeciesPeriod

19

Unadjusted comparison(-1992)

18

19

20

21

22

25 26 27 28 29 30 31

ln (unadj larval abund)

ln (

recr

uit

s)

Adjusted comparsion(-1992)

18.519

19.520

20.521

21.522

23 24 25 26 27 28 29

ln (adj larval abund)

ln (

recr

uit

s)

Adjusted comparsion(-1992)

18.519

19.520

20.521

21.522

23 24 25 26 27 28 29 30 31

ln (adj larval abund)

ln (

recr

uit

s)

Late larval abundance

Late larval abundance weighted for lengthand survey date using mean growth and mortality

Late larval abundance weighted for lengthand survey date using temperature dependentmortality and mean growth**significant at p<0.05

Sampling considerations

20

Life stage considerations

Prediction:from initial

conditions of environment and

spawning biomass: from larvalabundance

: from juvenile abundance

: from juvenilesand predatoroverlap

Recruitment level

Time

Abu

ndan

ce

Egg JuvenileLarval Recruit

Scheme of Continuous Refinement of Recruitment Forecast

Small scale….. increasing to…. large scale

Predominantly activating processes

: add habitat,densitydependence

Predominantly constraining processes

Hollowed and Bailey 2009

21

Rock sole

0

0.2

0.4

0.6

0.8

1

67 69 71 73 75 77 79 81 83 85 87 89 91 93 95year

Flathead sole

0

0.2

0.4

0.6

0.8

1

67 69 71 73 75 77 79 81 83 85 87 89 91 93 95year

Figure 1.--Estimated relative recruitment of Eastern Bering Sea flatfish species from

Arrowtooth flounder

0

0.2

0.4

0.6

0.8

1

67 69 71 73 75 77 79 81 83 85 87 89 91 93 95year

Rock sole

0

2000

4000

6000

8000

0 200 400 600 800 1000 1200

fit to 1978-88fit to 1989-961978-88 data1989-96 data

Arrowtooth flounder

0

200

400

600

800

0 200 400 600 800 1000

female spawning biomass (1,000s t)

1978-88 recruits1989-96 recruits1978-88 data1989-96 data

Flathead sole

0

400

800

1200

1600

0 100 200 300 400 500

Rec

ruit

men

t (1

,000

s)

1978-88 recruits

1978-88 data

1989-96 data

Index of Advection in the E. Bering Sea and effects on winter-spawning flatfish recruitment

Rel

ativ

e R

ecru

itmen

t

Transport to nursery areas, 1980-89

Transport away from nursery areas, 1990-97

Wilderbuer et al. 2002, Prog. Oceanogr. 55:235-246

22

Coupled Bio-Physical model forecasts Stockhausen AFSC

23

Assess Performance

northern rock sole recruitment

0

1

2

3

4

5

6

1980

1982

1984

1986

1988

1990

1992

1994

1996

1998

2000

2002

year class

recr

uit

men

t (b

illi

on

s)

on shelf wind drift

off shelf wind drift

mid shelf pattern

24

Incorporating Ecosystem Indicators into

Stock – Recruitment Equations

( )...)21( EEStt eSR ++−∗∗= βα

Brooks and Powers ICES J. Mar. Sci (2008)

Generalized compensation in stock – recruit functions

),0(~; 2)2/()(

11

2,1

Ry

Ia

y NeeeRR Ryyin

i i σσε

∑= −+

=

25

1960 1970 1980 1990 2000

-2-1

01

23

Year

Link torecruitment

Management Strategy Evaluation: Climate Impacts on Productivity

Age-structured operating model

Management Strategy

TACData

ClimateDecision ruleYears for

defining thecurrent regime

Climatedata

26

Cold Regime (Bottom-Up Regulation)

Beginning of Warm Regime (Bottom-Up Regulation)

Warm Regime (Top-Down Regulation)

Beginning of Cold Regime (Both Top-Down and Bottom-Up Regulation)

Oscillating Control Hypothesis

Zooplankton Larval Survival Abundance of Piscivorous Adult Fish Juvenile Recruits

Hunt et al. 2002

27

2

FEAST Higher trophic level model

NPZ-B-DLower trophic

level

ROMSPhysical

Oceanography

Economic/ecological model

Climate scenarios

BSIERP Integrated Integrated Integrated Integrated modeling

Observational Data

Ne

ste

d m

od

els

BE

ST

28

Comparative Assessment

29

PICES Comparative Approach

30

Month

SpeciesPICES Region Mechanism Index 1 2 3 4 5 6 7 8 9 10 11 12

Walleye pollock GOA

Spawning pre-conditoning(subsurface flow into Shelikof Strait)

Wind Advection

57N, 156W

57N, 156W

GOALarval transport to nursery area

Wind Advection

57N, 156W

GOA Hatch date Temperature 40m

57N, 156W

57N, 156W

GOA

Larval encounter with prey (eddy formation) Precipitation

57N, 156W

57N, 156W

GOALarval encounter with prey Wind Mixing

57N, 156W

57N, 156W

GOA

Larval metabolic rate (growth out of predator range)

Temperature 40m

57N, 156W

57N, 156W

GOA

Duration of summer feeding season (time of stratification)

Solar heat + Wind mixing (timing of stratification)

57N, 156W

57N, 156W

57N, 156W

GOA

Age 0 metabolic rate (growth overwintering success)

Temperature 40m

56N, 157W

56N, 157W

56N, 157W

GOA

Summer prey habitat concentration

Mixed Layer Depth

56N, 157W

56N, 157W

56N, 157W

GOA

Summer prey availability (Basin-Shelf exchange)

Wind Advection

57N, 156W

57N, 156W

57N, 156W

31

Common mechanisms 25 North Pacific Stocks

Mechanism Total

Timing of spring bloom / Spring freshet 7

Abundance of prey for first feeding larvae 8

Hatch date / run timing 9

Concentration 3

Temperature - Metabolic rate 16

Timing of stratification (solar heat + wind mixing) 3

Duration of summer feeding period 5

Wind advection to nursery areas 12

Wind - sustained summer production 12

Settlement habitat volume / watermass 10

Maternal condition 5

Predator abundance 4

Predator distribution 4

Competition - hatchery 2

32

A way forward

Short term: —Form strong interdisciplinary research teams—Conduct deterministic retrospective studies to identify

potential linkages.—Conduct field studies to assess mechanisms.—Develop - mathematical representations of key processes

incorporating ecosystem indicators. —Observe and predict and assess skill.

Medium term 2012:—Couple ocean circulation, prey production, fish production

and predation with spatial and temporal feedbacks (BSIERP).

—MSE A’mar (GOA pollock) Punt and Ianelli (BSAI pollock), rock sole (Wilderbuer), P. cod (A’mar and Thompson)