NEMURO.FISH: A NPZ-Fish Bioenergetics/Population

Dynamics Model for Pacific Saury and Herring

by

Bernard A. MegreyFrancisco E. Werner

Process:

10 workshops over 7 years

strong international collaboration

several funding sources

Acknowledgments

We are grateful to our sources of funding: • North Pacific Marine Science Organization (PICES)• City of Nemuro Japan• Heiwa-Nakajima Foundation • Japan International Science and Technology

Exchange Center• Japan Fisheries Research Agency • Asia-Pacific Network• GLOBEC

Primary CollaboratorsKenneth Rose, Louisiana State University, USA

Rob Klumb, Great Plains Fish and Wildlife Management Assistance Office, USA

Douglas Hay, Pacific Biological Station, Canada

Dan Ware, Nanaimo, BC, Canada

Shin-ichi Ito, Tohoku National Fisheries Research Institute, Miyagi, Japan

Dave Eslinger, NOAA Coastal Services Centre, USA

Yasuhiro Yamanaka, Graduate School of Environmental Earth Science, Hokkaido, Japan

Michio J. Kishi, Graduate School of Fisheries Sciences, Hokkaido, Japan

Maki Aita-Noguchi & Lan Smith, Frontier Research Center for Global Change, Yokohama, Japan

Outline

• Motivation: Charge to the PICES CCCC Model Task Team

• Background on N. Pacific Ocean Dynamics• Modeling approach – NEMURO LTL &

HTL• Example applications, model calibration

and uncertainty analysis• Future work

PICES Climate Change & Carrying Capacity (CCCC) Program

• Ultimate Goal……

“to forecast the consequences of climate variability on the ecosystems of the subarctic North Pacific”

• Acknowledges that long-period changes occur in the PICES region and assumes that changes in zooplankton biomass, productivity and species composition will lead to changes in the carrying capacity of the subarctic Pacific

Regimes and the Pacific Regimes and the Pacific Decadal OscillationDecadal Oscillation

• an El Niño-like pattern of climate variability

• 20 to 30 year periods of persistence in North American and Pacific Basin climate

• warm extremes prevailed from 1925-46, and again from 1977-98; a prolonged cold era spanned 1947-76

19981925 1947 1977

Mantua, Hare, Zhang, Wallace and Francis, BAMS 1997Mantua, Hare, Zhang, Wallace and Francis, BAMS 1997

(Rodinov and Overland, 2005))

“Regimes” evident in HTL fish stocks

CCCC Model Task Team Recommendations

• Since comparison of 12 regional ecosystems is at the core of the CCCC, a prototype LTL model should be adopted to examine climate impacts

• The prototype model should have a generalized structure that can correctly represent the characteristics of each system

• Structural and formulation differences should be minimized

• Prototype model will facilitate development of comparison protocols

Lower Trophic Level Modeling

OBJECTIVE:

Used as a tool to test the hypothesis that physical forcing factors regulate primary production and that the effect is apparent in zooplankton standing stock and then transferred to variation in higher trophic levels

NEMURO LTL• 1st workshop held in Nemuro Japan 2000• Participants – physical oceanographers, biological

oceanographers, fisheries oceanographers, fisheries biologists, oceanographic modelers, fisheries population dynamists, applied mathematicians

• A consensus conceptual model was designed representing the minimum trophic structure and biological relationships between and among all the marine ecosystem components thought to be essential in describing ecosystem dynamics in the North Pacific

• NEMURO-A compromise between generality and complexity

NEMURO

North Pacific Ecosystem Model

for Understanding Regional

Oceanography

NEMURO

• 1D point model; 2 layers

• 2 phytoplankton groups; 3 zooplankton groups

• Fluxes calculated for nitrogen and silicate

• Sinking of POM and Opal

• Primary Production limited by nutrients (NO3 and NH4 via Michaelis-Menten), temperature (Q10), and light (self shading)

• Grazing via Ivlev function and temperature influence (Q10)

• Nutrient exchange between the deep and mixed layers

• Forced by annual signals of light, SST and MLD

• NO IRON

NEMURO Features

Links to the Physics and Climate• All biological rates mediated by sea temperature• Ontogenetic large zoop vertical migration (where

appropriate based on local conditions of T and light)• Location specific physical variables

– Seasonal light– Mixed layer depth– Nutrient flux from bottom layers– Air temperature for fish recruitment function– NPPI index for fish recruitment function– Water temperature for fish recruitment function– Prey fields (for static coupling)

• Basin-scale climatology

Parameter sets were assembled for three areas of the North Pacific Ocean

Apply the same model structure and climate scenarios to three different ecosystems – any observed differences in dynamic response will be due to locale characteristics

and forcing

Example of model results that include state variable dynamics (top panel) as well as time dependent dynamics of the diagnostic variables (bottom panel).

Phyto P/B ratios

Zoop P/B ratios

Zoop C/B ratios

Ecotrophic Efficiency

Linking the lower trophic level model to higher trophic levels

Development of NEMURO.FISH

NEMURO.For Including Saury and

Herring

Rationale• Increasing appreciation of climate effects on fish

growth, recruitment, and population dynamics• Observed “regimes” of varying productivity in

exploited fish stocks• Recognition that effective management requires

understanding and quantitative tools (models) for predicting climate effects on fish populations

Herring in the North Pacific• Extensive long-term data on size at age for

multiple locations around the Pacific Rim• All life stages eat zooplankton• Life history and biology well known• Goals:

– (1) better understand intra- and inter-population

variation in herring growth and survival– (2) relate results to climate change and carrying

capacity

NEMURO.FISH

Fish Bioenergetics Governing Equation

)(TfWaC Cb

CMAXC

( ) z

f

CALdWC R S F E H W

dt CAL

1

1

j ijMAX

ijj n

k ik

ikk

PD vC

KC

PD v

K=

××

=×

+å

W = weight (g ww)C = consumption (1/day)

R = respirationS = SDA

F = egestionE = excretion

H = reproductionCalz – caloric value of prey

Calf – caloric value of herring

PD = prey density (1=ZS; 2=ZL; 3=ZP)V = vulnerability

K = feeding efficiency

n

jjr CC

1

Respiration

TcbA

AA eWaU

VTfWaR Rb

RR )(

TcR

ReTf )( UdReV

Process formulation different for age 0, 1 2+

Herring Population Dynamics

• Age structured (11 age classes)

• Stage structured (feeding and biological process description specific to ontogenetic stage, age 0, age 1, age 2+)

• Realistic reproductive biology (closed life cycle)– Environment-dependent function to generate recruits

– Age-specific maturity schedules

– Age-specific fecundity schedules

• Seasonal energy density of herring

• Age-specific fishing removals and natural mortality

iiii NMF

dt

dN

RNMFdt

dN

)(

)( 11111

YOY Recruitment

SSB - spawning stock biomass (g wet weight/m3)

NPPI - North Pacific Pressure Index

AIR - Air temperature

SST - Sea surface temperature

(Williams and Quinn. 2000. Fish Oceanogr 9: 300-315)

3.24 0.032 0.44 - 0.26 - 0.36-3•10 • t t t tSSB NPPI AIR SSTtYOY SSB e

Benefits of Using Environment-Dependent SR Model

• Produces observed autocorrelation in recruitment time series

• Reproduces observed recruitment variation on annual and multi-decadal time scales

• Closed life cycle allows the stock to become self-sustaining after initialization

• More realistic compared to constant recruitment assumptions

• Important feature for regime shift and climate change scenario hypotheses as it allows direct environmental effects on recruitment influencing top down control

Computations

• Differential equations solved with 4th order Runge-Kutta numerical solution technique

• dt=1 hour

Saury

Three Main Age Groups

• Biological process do not simply scale with size/age. Sometimes there are different processes unique to a life stage…..

• Age 0 (age of a recruit)

• Age 1 (0-12 month)

• Age 2+ (24 months and older) ~180g ww

30

35

40

45

130 135 140 145 150 155 160 165

Kuroshio Extension

Oyashio Front

spawning groundin winter

spawning groundin spring & autumn

Mixed water region

Migration

Migration

Feeding groundin summer

Fishing groundin autumn

Life History of Pacific Saury with Oceanographic Features

Modified from Watanabe et al. (1989)

Table 2. Life stages of Pacific saury in the saruy bioenergetics modelStage region 　　　　larvae Kuroshiojuvenile & young mixed regionsmall Oyashioadult mixed regionadult matured Kuroshioadult mixed regionadult Oyashioadult mixed regionadult matured Kuroshio

3-box version

OyashioMixed Waterregion

Kuroshio

9 life stages

Ito et al. (2004)

30

35

40

45

130 135 140 145 150 155 160 165

Interannual Forcing (SST)

Oyashio

Mixed Water Region

Kuroshio

JMA SST product (1deg x 1deg, 10days)1950 - 2002

Two Example Applications• Dynamic mode

– fish consumption removed from zooplankton, excretion adds NH4, and egestion adds PON

– quasi-West Vancouver Island (WVCI)

• Uncoupled mode– NEMURO imbedded a 3-D circulation model (Aita-

Noguchi et al., 2004)– predicted temperature and zooplankton used to drive

herring model

Latitudinal Variation in Herring Growth

An Uncoupled Example

• Used predictions of temperature and zooplankton density from NEMURO imbedded in a 3-D circulation model (Aita-Noguchi et al. 2004).

• Data available from 1948-2002

• Look at regional response in herring growth. Do regime shifts cascade up the food web?

3D Model BackgroundPhysical model: CCSR Ocean Component Model (COCO) 3.4 (developed at Center for Climate System Research,

University of Tokyo)

Biological model: NEMURO LTL

Configuration (same as Aita et al., 2003) Horizontal resolution : 1 degree * 1degree (360x180). Vertical resolution : 54 levels from the surface to the bottom

(5000m). 5m for all layers within upper 100m. Mixed layer processes: Noh and Kim turbulent closure scheme.

Boundary conditions (daily surface forcing) NCEP 6-hourly dataset from 1948 to 2002 : Sea surface temperature : Fresh water flux : Surface wind stress : Solar radiation Nitrate and Silicate concentrations: WOA 1998

NEMURO.FISH applied to four areas of the North Pacific

Prince William Sound

Hokkaido-Sakhalin

West Coast Vancouver

Island

Oregon Coast

Year

1950 1960 1970 1980 1990 2000

Wat

er T

empe

ratu

re (

oC

)

0

2

4

6

8

10

12

14

Bering SeaPrince William SoundWest Vancouver IslandOregon Coast

Bering Sea

0.0

0.1

0.2

0.3

0.4

Prince William Sound

Co

nce

ntr

atio

n (

g w

w/m

3)

Small zooplanktonLarge zooplanktonPredatory zooplankton

West Vancouver Island

Oregon Coast

Year1950 1960 1970 1980 1990 2000

Dynamic Example

• Calibrated NEMURO to field data on phytoplankton and zooplankton for WVCI– monthly concentrations– automated calibration with PEST software

• Used historical environmental indices for recruitment (Williams and Quinn, 2000)

Model Calibration• NEMURO and NEMURO.FISH are complex models with

many parameters (190)

• Usually ad-hoc methods are used to calibrate ecological models where one “manually adjusts favorite parameters until a subjective good fit of predicted and observed values”

• We want to apply NEMURO to multiple locations throughout the open ocean and also to coastal environments for coupling to herring, saury and other models.

• Need an objective way to calibrate the model

PEST Automatic Calibration Software

• Need only PEST setup files and an executable model

• Variation of Gauss-Marquardt-Levenberg algorithm

• Minimize the weighted sum of squared deviations between predicted and observed values

• Relationship between model and parameters approximated by a Taylor series expansion, involves computing the Jacobian and Hessian matrices

PEST

NEMUROPEST

Input Parameters

Output Variables

Observations

Setup Files

Calibration Data

• West Vancouver Island: 1991-2001• California Current

– Wainwright et al.– Wang

• Created a dataset of monthly values of nitrate, total phytoplankton, small zooplankton, large zooplankton, and predatory zooplankton

(b) Small Zooplankton

0.0

0.1

0.2

0.3(a) Total Phytoplankton

0.0

2.5

5.0

7.5

WVCICalifornia Current

(c) Large Zooplankton

Co

nce

ntr

atio

n (

mic

ro-m

ole

s N

/Lite

r)

0.0

0.2

0.4

0.6(d) Predatory Zooplankton

0.0

0.1

0.2

0.3

Month

0.0

0.3

0.6

0.9

Month

0

10

20

30(e) Total Zooplankton >200 microns (ZL+ZP)

(f) Nitrate

(d) Small Zooplankton

0.0

0.1

0.2

0.3

(a) Total Phytoplankton

0.0

2.5

5.0

7.5

Field dataAd-hocPEST

(e) Large Zooplankton

0.0

0.2

0.4

0.6(f) Predatory Zooplankton

0.0

0.1

0.2

0.3

(b) Small Phytoplankton

0.0

1.5

3.0

(c) Large Phytoplankton

Co

nce

ntr

atio

n (

mic

ro-m

ole

s N

/Lite

r)

0.0

1.5

3.0

(g) Total Zooplankton >200 microns (ZL+ZP)

Month

0.0

0.3

0.6

0.9 (h) Nitrate

Month

0

10

20

30

12 14 16 18 20 22 24 260

2

4

6

Simulated Year

Tot

al B

iom

ass

(g w

w/m

2 )

12 14 16 18 20 22 24 260

100

200

300

Simulated Year

Wei

ght

(g w

w)

1

23

4

5

6

7

89

10

0 20 40 60 80 100 120 1400

100

200

300

Month

Wei

ght

(g w

w) Predicted Size-at-age

Observed-Size-at-age

Herring Calibration

saury (150E) pest for phalf's & ac

0

50

100

150

200

0 200 400 600 800

age (date)

wet

wei

ght

WobsWinitWpest+ac

Saury Calibration

Uncertainty Analysis

I21

Model

Run P1 P2 P3

Value of Output

Variable

1 I14 I23 I35 Y1

2 I12 I21 I36 Y2

3 I11 I26 I31 Y3

4 I16 I24 I34 Y4

5 I13 I22 I33 Y5

6 I15 I25 I32 Y6

Latin Hypercube Monte Carlo Sampling

I22 I23 I24 I25 I26

I13

I34 I35I33I32 I36I31

I14 I15I12I11 I16

P1

P2

P3

Sensitivity Analysis

Sensitivity of Total Population

Biomass and Weight-at-age 5

under conditions of

Low Fish Biomass-High Prey Biomass

High Fish Biomass-Low Prey Biomass

NEMURO ECOPATH/ECOSIM

Data Flow

LTL

HTL

NEMURO ECOPATH/ECOSIM Linkage

Fine temporal scale

Mechanistic

Process oriented

Course temporal scale

Aggregated

Approximate ecosystem through P/B and C/B ratios

Climate Change Scenario

Concluding Remarks

Work is (clearly) ongoing, but:

• We have linked the LTL with the HTL successfully in certain locations and for two fish species with very different life histories

• Both dynamic and one-way coupling versions yield interesting result

Future Work

• Complete publications – special issue of Ecological Modelling

• Extensions to sardines and anchovies (Fall 2005)

• Spatially explicit

• Future climate change scenarios

5 NEMURO Posters• Yamanaka, Hashioka, Aita, and Kishi. Changes in ecosystem

and pelagic fish in western North Pacific associated with global warming

• Terui and Kishi. Population dynamics model of Copepoda in the Northwestern Pacific

• Aita, Tadokoro, Yamanaka, and Kishi. Interdecadal variation of the lower trophic ecosystem in the Northern Pacific between 1948-2002-in a 3D implementation of the NEMURO model

• Hashioka and Yamanaka. Seasonal and regional variations in phytoplankton groups by top-down and bottom-up controls obtained by a 3D ecosystem model

• Nakajima, Hashioka and Kishi. Analysis of spatial differences in wet weight of Japanese common squid in the Japan Sea