GLOBEC NWA Program: Phase 4B Synthesis FVCOM-NPZD- Copepod Dynamics Calanus Diapause Larval Fish Dynamics Basin-scale Calanus IBM Data/model synthesis working group Global-Basin-Regional interactions

Modeling copepod population dynamics in the GB-GOM region Cabell Davis, Qiao Hu, Rubao Ji

Biomass at Age Spawning Stock Biomass Number of Recruits Stock ̶ Recruitment Georges Bank Haddock GLOBEC Georges Bank Objective: To understand the processes controlling recruitment of cod and haddock and their dominant prey species.

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

The copepods: Calanus Pseudocalanus Oithona 1 mm Centropages Hopcroft Davis Temp & Food Dependent: Fertility Molting Growth Mortality

Copepods vs Year Salinity Anomaly Broad-scale Phytoplankton vs Salinity Cod & Haddock Growth vs Copepods Cod & Haddock Mortality vs Year Cod & Haddock Mortality vs Salinity Anomaly Results (cont): Broadscale Surveys

1990s Freshening Freshwater in early 1990s traced to Arctic –AO+ winds strengthen Beaufort Gyre –AO - winds release freshwater 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

NPZDCopepodsFish larvae Nutrients Detritus Phytoplankton Micro-Zooplankton CBM IBM

Larval Fish Modeling, Lough, Werner et al. Lough et al Fish. Oceanogr. 14:4,

Physics Nutrients and Phytoplankton Copepod Species Input data FVCOM model Model Output 3D Distributions of T, S, u, v, w, N, P, μZ, D, and copepod species over the period

S1: Uptake (P on N) S1=μ max f(I)f(N)f(T)P S2: Grazing (Z on P) S2=g max f(P)f(T)Z S3: Loss of P S3=λ P S4: Remineral. of D S4=εD S5: Loss of Z S5=mZ 2 N P µZµZ 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=μ max f(I)f(N)f(T)P S2: Grazing (Z on P) S2=g max f(P)f(T)Z S3: Loss of P S3=λ P S4: Remineral. of D S4=εD S5: Loss of Z S5=mZ 2 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 age-stage classes, 13-stages ENCA Time (d) stage, ENCA ENC A Number of individuals 200 age-stage classes, 13-stages (Hu et al., submitted) Time t Time t+1

Nauplii Pseudocalanus, 1995 Eggs CopepoditesAdults

Pseudocalanus adults MARMAP data, (McGillicuddy et al. 1998) J F M A M J J A S O N D Pseudocalanus C1-C6 Abundance (#/m 3 ) 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, Cohort Age Abundance Cohort Age Abundance vs Chronic 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