GLOBEC NWA Program: Phase 4B Synthesis

FVCOM-NPZD-Copepod Dynamics

Calanus Diapause

Larval Fish Dynamics

Basin-scale Calanus IBM

Data/model synthesis working groupGlobal-Basin-Regional interactions

Modeling copepod population dynamics in the GB-GOM region

Cabell Davis, Qiao Hu, Rubao Ji

Biomass at Age

0 2 4 6 8 10 12 14 16 18

x 104

2.5

3

3.5

4

4.5

5

5.5

6

Spawning Stock Biomass

Num

ber

of

Recr

uit

s

Stock ̶� ̶Recruitment

Georges Bank Haddock

GLOBEC Georges BankGLOBEC Georges Bank

Objective:Objective:

To understand the To understand the processes controlling processes controlling recruitment of cod and recruitment of cod and haddock and their haddock and their dominant prey species.dominant prey species.

Georges Bank cod/haddock spawning and larval and juvenile drift (Lough and Manning, 2001)

Pratt

Haddock larva

The copepods:

Calanus PseudocalanusOithona

1 mm

Centropages

Hopcroft

Hopcroft

Hopcroft

Davis

Temp & FoodDependent:

FertilityMoltingGrowthMortality

-1

0

1

2

3

Me

an

No

rma

lize

d D

evi

atio

n

1994 1995 1996 1997 1998 1999 2000

Metridia

Temora

Oithona

Centropages

Pseudocalanus

Calanus

Mean

Copepods vs Year

1992 1994 1996 1998 2000 2002-1.5

-1.0

-0.5

0.0

0.5

500

450

400

350

300

250

Salinity Anomaly

-1.5

-1

-0.5

0

0.5

1

1.5

2

Ch

loro

phy

ll

-0.015 -0.01 -0.005 0 0.005 0.01 0.015

Salinity

y = -36.961x + 0.000 r 2 = 0.180

June

May

Apr

Mar

Feb

Jan

Broad-scale Phytoplankton vs Salinity

-1.00 -0.60 -0.20 0.20 0.60 1.00

Normalized Residual Prey

-0.04

-0.03

-0.02

-0.01

0.00

0.01

0.02

Resid

ual G

rowt

h (

d-1

)

Cod & Haddock Growth vs Copepods

Cod & Haddock Mortality vs Year

Salinity Anomaly

-1.2 -1.0 -0.8 -0.6 -0.4 -0.2 0.0E

arly

Lar

val M

ort

alit

y

0

2

4

6

8

10

Cod & Haddock Mortality vs Salinity Anomaly

Results (cont): Broadscale Surveys

1990s Freshening1990s Freshening

Freshwater in early Freshwater in early 1990s traced to Arctic1990s traced to Arctic– AO+ winds strengthen AO+ winds strengthen

Beaufort GyreBeaufort Gyre– AOAO-- winds release winds release

freshwaterfreshwater

Greene and Pershing, 2007 Science

Present Work, Synthesis: Models

Regional-scale Model Basin-scale Model

FVCOM Integrated Model System

Concentration-based Food-web and

Copepod Species Models

NPZD Copepods Fish larvae

Nutrients

Detritus

Phytoplankton

Micro-Zooplankton

CBM CBM IBM

Larval Fish Modeling, Lough, Werner Larval Fish Modeling, Lough, Werner et al.et al.

Lough et al. 2005. Fish. Oceanogr. 14:4, 241-262

Physics Nutrients andPhytoplankton

CopepodSpecies

Input data

FVCOM model

ModelOutput

3D Distributions of T, S, u, v, w, N, P, μZ, D, and copepod species over the period 1995-1999

S1: Uptake (P on N)S1=μmaxf(I)f(N)f(T)P

S2: Grazing (Z on P)S2=gmaxf(P)f(T)Z

S3: Loss of PS3=λ P

S4: Remineral. of DS4=εD

S5: Loss of ZS5=mZ2

N

P

µZ

D

S1

S2

S3

S4

βS2

γS5

S5

(1-α-β)S2

αS2

Eggs

Nauplii

Copepodids

Adults

Copepod Population

Lower Food Web

S1: Uptake (P on N)S1=μmaxf(I)f(N)f(T)P

S2: Grazing (Z on P)S2=gmaxf(P)f(T)Z

S3: Loss of PS3=λ P

S4: Remineral. of DS4=εD

S5: Loss of ZS5=mZ2

N

P

Z

D

S1

S2

S3

S4

βS2

γS5

S5

(1-α-β)S2

αS2

Eggs

Nauplii

Copepodids

Adults

Copepod Population 4-Stage (ENCA)

Lower Food Web

Numerical Diffusion & Mean-Age Model

100

0

100

0

200 age-stage classes, 13-stages

E N C A

Time (d) 700

100

0

4-stage, ENCA

E N C A

Nu

mb

er

of

ind

ivid

uals

200 age-stage classes, 13-stages

moltstage

stagestagestage

NN

NAA

)1(

(Hu et al., submitted)

Time t Time t+1

Nauplii

Pseudocalanus, 1995Eggs

Copepodites

Adults

j f m a m j j a s o n d j0

0.5

1

1.5

2

2.5

3

3.5

4x 10

4

j f m a m j j a s o n d0

1

2

3

4x 10

4

Pseudocalanus adults MARMAP data, (McGillicuddy et al. 1998)

J F M A M J J A S O N D

0

104

Pseudocalanus C1-C6 Abundance (#/m3)

0-D Mean-age Model

1. How do we parameterize mortality? Whole populations: Inverse methods: Ohman, Nisbit & Wood; McGillicuddy adjoint; Hall ‘64

Patchy Predators: Predation by planktivorous fish, schooling herring/mackerel Small scale patchiness, ctenophores

Gelatinous predation, sparse data

The recruitment problem, exponential losses,

106

0

Cohort Age

Abu

ndan

ce

10100

106

0

Cohort Age

Abu

ndan

ce

10100

0.0500 vs 0.0475Chronic vs Episodic Mortality

Some questions

More Questions:

2. One-way versus two-way coupling? “NPZD” structured mesozooplankton IBM or CBM? How detailed? i.e., what details matter? Behaviors? DVM, food-seeking, mate-seeking

3. What is food? Chlorophyll, C, N Food quality? Nutrition: protein, lipid, carbs Encounter rate, turbulence, pred/prey swimming

End