Potential Approaches Empirical downscaling: Ecosystem indicators for stock projection models are projected from IPCC global climate model simulations. Dynamical downscaling: IPCC simulations form the boundary conditions for regional bio- physical numerical models with higher trophic level feedbacks. Fully coupled bio-physical models that operate at time and space scales relevant to regional domains (impractical at present).

Predation Spawning Early larvae (spring) Late larvae (fall) Age-1 recruits Spatial distribution Biomass Consumption rate Prey composition Spring conditions (Late) summer conditions Prey Timing of ice retreat Spring SST Prey Summer SST Wind mixing Stability

Estimated effects of summer SST & predation on log-recruitment R 2 =0.44 P = Prediction interval Simulate effect of increase in average SST on recruitment at three levels of predation Low Med High

Dynamical Modeling Physical Forcing (Wind, temp, sun) Nutrients NO 3, NH 4… Primary Producers (Phytoplankton) Secondary Producers (Zooplankton) Higher trophic levels (Pollock etc.)

Horizontal resolution: ~10km, vertical resolution: 60 layers Computes physical properties i.e. temperature, salinity currents BEST-NPZ model coupled to ROMS at every grid point and time-step ROMS Physical Oceanography Model

EUPHAUSIIDS LARGE COPEPODS MICROZOOPLANKTON SMALL PHYTOPLANKTON LARGE PHYTOPLANKTON NITRATE AMMONIUM Slow sinking DETRITUS IRON SMALL COPEPODS Excretion + Respiration WATER Mortality Predation Egestion JELLYFISH Fast sinking DETRITUS Inexplicit food source ICE ALGAE NITRATEAMMONIUM BENTHIC FAUNA BENTHIC DETRITUS ICE BENTHOS

Model Validation: Data availability Location of nitrate data used: All months, all years

Model Validation: Primary Production Observations from Rho, Whitledge and Goering (1997) Simulated Observed Monthly mean daily primary production: Middle Shelf Simulated Observed

Zooplankon Biomass Day Microzooplankton5.916 Small Copepods Large Copepods Euphausiids E-5 Compares ‘reasonably’ well to Coyle data … – but will the fish have enough to eat ?

Model Predictions: Ecosystem Projections Euphausiid production: Annual average for shelf break A single projection CCC MA Ensemble of runs will define upper and lower limits of projection g C m Zooplankton biomass: Depth integrated at M2 mooring

FEAST model for forage species and predators Bioenergetics of feeding, growth, spawning Focus on data-driven functional response between predator and prey Use allometric relationships for rates Diet preferences based on stomach data Movement (towards prey concentrations, away from poor conditions, migration for spawning) Currently includes pollock, cod, and arrowtooth flounder

Diet fitting by region Prey Type (proportion in diet) by pollock body length (0-80cm) region 3 size classes of copepod in model summed for fitting amphipods, shrimp stomachs sampled by pollock length by region

Combined BTS+Acoustic survey vs FEAST

FEAST age-0 seasonal forage potential and stock-assessment estimate of year-class strength Colors: stock- assessment year-class strength Blue weakest Red strongest Domain 8 (outer northwest shelf) Week of year Age 0 foraging potential