Modeling at AFSC Kerim Aydin, Sarah Gaichas, John Heifetz, Sarah Hinckley, James Ianelli, Pat Livingston, Bern Megrey, Jesus Jurado-Molina, Michael Dalton, Ivonne Ortiz, and Buck Stockhausen Kerim Aydin, Sarah Gaichas, John Heifetz, Sarah Hinckley, James Ianelli, Pat Livingston, Bern Megrey, Jesus Jurado-Molina, Michael Dalton, Ivonne Ortiz, and Buck Stockhausen Subset shown in talk: see abstracts for full list Subset shown in talk: see abstracts for full list

Two major scales of modeling Long-term (50+year) predictions Long-term (50+year) predictions –Driven by Climate Change predictions: LOSS OF SEA ICE and OCEAN ACIDIFICATION: Primarily Biophysical->fish models (bottom-up) Interface with current management Interface with current management –Folding currently operational models in with the stock assessment and Council processes: MRM and ecosystem models Feely et al Impact of anthropogenic CO 2 on the CaCO 3 in the oceans. Science 305: M. Litzow and J. Short, NOAA Alaska Fisheries Science Center

NEMURO: North Pacific Ecosystem Model for Understanding Regional Oceanography “A conceptual model representing the minimum trophic structure and biological relationships between and among all the marine ecosystem components thought to be essential to describe ecosystem dynamics in the North Pacific” (An MRM for NPZ modeling?) Shown is NEMURO.FISH extension Source: Megrey et al. 2007

Gulf of California California Current West Coast Vancouver Island Station P Prince William Sound Bering Sea Aegean Sea East China Sea Yellow Sea Hokkaido Island Sea of Okhotsk Marine Seas where the NEMURO Model has been Applied

Western Alaskan Sockeye British Columbia Sockeye Central Alaskan PinkJapanese Chum Predicted effect of climate change on pink salmon growth: 10% increase in water temperature leads to 3% drop in mature salmon body weight (physiological effect). 10% decrease in pteropod production leads to 20% drop in mature salmon body weight (prey limitation). (Aydin et al. 2005) Consumption and mortality rates for Pink salmon based on predator and prey biomass. Pink salmon bioenergetics model, predicts daily pink salmon growth and numerical mortality based on input ration. Ecosim (ecosystem biomass dynamics model), run on a daily timestep. Daily biomass density of phytoplankton, microzooplankton, large zooplankton (copepods). NEMURO (nutrient-phytoploankton-zooplankton- detritus): 1-dimensional water column model integrated on an hourly timestep. Pink salmon body weight and numbers used to set Ecosim biomass for predator and prey equations in next timestep.

Larvae have behavior! preferred night time depth range preferred daytime depth range + Growth, Mortality DisMELS: Dispersal Modeling for Early Life Stages (Stockhausen)

(A. Hermann) ROMS 3D Hydrodynamic Model Output IBM for Early Life History Stages Egg Stage 1 Larval Stage 1 Egg Stage N Larval Stage M DisMELS and ROMS (one of multiple efforts interfacing with ROMS)

PET-ISAM Model for Integrated Assessment Population- Environment- Technology Model coupled to Integrated Science Assessment Model ISAM used to analyze climate change and ocean acidification (Cao, Caldeira & Jain, GRL 2007) PET Model CO2 Emissions

AIM: Coupled PET-ISAM-EwE Households Capital & Labor Consumption & Savings Final Goods Producers Consumption Investment Government Exports & Imports Intermediate goods producers Agriculture Fisheries Forests Energy Everything Else (ETE) K & LC & I E & M ISAM EwE/ Ecosense Seafood CO2, GHGs Climate

Integration with management Conservative exploitation rates/productive stocks (unless you’re a crab). Conservative exploitation rates/productive stocks (unless you’re a crab). Declining mammal and bird stocks (fisheries management with Endangered Species Act considerations) Declining mammal and bird stocks (fisheries management with Endangered Species Act considerations) Pro-active management: ecosystem committee, ecosystem considerations chapter, but also pro-active lawsuits Pro-active management: ecosystem committee, ecosystem considerations chapter, but also pro-active lawsuits Recent declines in most valuable fishery, the walleye pollock (CASE STUDY for both strategic and tactical integration) Recent declines in most valuable fishery, the walleye pollock (CASE STUDY for both strategic and tactical integration) Steller Sea Lions Steller Sea Lions Aleutian Islands Fisheries Ecosystem Plan Aleutian Islands Fisheries Ecosystem Plan

“This” generation Multispecies Bycatch Model: Multispecies Bycatch Model: –Technical (Gear) interactions, age structured with detailed management scenarios, no predator/prey links MSVPA/MSFOR/MSM/MAMAK MSVPA/MSFOR/MSM/MAMAK –Multispecies age structured predator/prey for 7 target species, adds explicit predation effects to recruitment hindcasts Ecopath/Ecosim Ecopath/Ecosim –Includes non-target and protected species dynamics, gear, limited age structure (primarily biomass dynamics) An “operational ensemble?” An “operational ensemble?”

INTEGRATION WITH STOCK ASSESSMENT PROCESS Initially driven by NEPA, but now strongly positive interactions on all levels Ecosystem Considerations in each stock assessment Ecosystem Assessment –Multispecies models –Ecosystem Status Indicators –Ecosystem-Based Mngt Indices

Complexity vs. management reality Eastern Bering Sea Gulf of Alaska

Scoping/strategic analysis GOA predation vs. fishing 2005 Both F and M (Assessment Fig 9)

Strategy implications? Eventual goal. F>>M2F,M2M2>>F HighSingle-species management of highly (over-?) exploited species. Single-species management may be insufficient to guarantee long-term stability without large swings/ multispecies effects. Fully utilized species within food web, monitor for production issues, extremely limited fishery. MediumSingle-species management of fully exploited species. Concern over multispecies implications of fishery. Partially utilized species within a food web, some concern over fishery. LowSingle-species management of species with low exploitation. Low concern. (Fishing+Predation)/ Production F>>M2F,M2M2>>F HighSingle-species management of highly (over-?) exploited species. Single-species management may be insufficient to guarantee long-term stability without large swings/ multispecies effects. Fully utilized species within food web, monitor for production issues, extremely limited fishery. MediumSingle-species management of fully exploited species. Concern over multispecies implications of fishery. Partially utilized species within a food web, some concern over fishery. LowSingle-species management of species with low exploitation. Low concern. F>>M2F,M2M2>>F HighSingle-species management of highly (over-?) exploited species. Single-species management may be insufficient to guarantee long-term stability without large swings/ multispecies effects. Fully utilized species within food web, monitor for production issues, extremely limited fishery. MediumSingle-species management of fully exploited species. Concern over multispecies implications of fishery. Partially utilized species within a food web, some concern over fishery. LowSingle-species management of species with low exploitation. Low concern.

Broad strategic scoping leads to MRMs, and PARAMETER ESTIMATION/VALIDATION MSVPA and Multispecies Statistical Model Walleye pollock Pacific cod Fishery Arrowtooth flounder (Ianelli and Jurado-Molina) MCMC integrated profile of M

MAMAK: Aleutian fisheries (Kinzey and Punt) Walleye pollock, Atka mackerel, and Pacific cod provide the basis for the major fisheries of the Aleutian shelf, Alaska. All three species interact as predators and prey. Spawning stock biomass Predation “off”: black dashes Predation “on” Types I-VII functional responses: blue lines Type II: asymptotic Type I: linear Type III: S-shaped Type IV: ratio interference Type V: ratio pre-emption, asymptotic Type VI: Hassel-Varley Type VII: “Ecosim”

Calculating Ecosim uncertainty (Extended fitting methods applied to multiple functional responses, extended equations, challenging the “primary production anomaly” methodology.) Gaichas and Aydin

Direct “tactical” uses : A Tale of Two Ecosystems Eastern Bering Sea Gulf of Alaska

Arrowtooth biomass vs. pollock M Shrimp biomass vs. pollock M Best fit functional responses (1970-present) dichotomous based on assumed forcing source (e.g. bottom-up vs. arrowtooth larval advection). Method: Test all hypotheses. GOA Long term: MSE

EBS additional concerns: Zooplankgon and forage fish biomass This continued low level of forage was (qualitative) reason for caution for pollock discussed by BSAI Plan Team (Assessment Fig. 3)

Evolution of single-species assessments to include advice from multispecies models and indicators From North Pacific Fisheries Management Council’s Scientific and Statistical Committee minutes, December 2006: “The [eastern Bering Sea walleye pollock] stock remains above the MSY level, having declined … at a rate of about 19% per year….A series of 4 below-average recruitments has contributed to the decline…the series of low recruitments will result in an age-structure that is dominated by only a few year-classes which could increase fluctuations in the population.” “Other issues raised in the stock assessment suggest a need for further caution.” –a northward shift … with some portion of the population into Russian waters. –a large decline in zooplankton, which is important in providing forage for juvenile pollock. –increasing predation by arrowtooth flounder on juvenile pollock, which could contribute to further declines in adult pollock biomass. “Consequently, the SSC agrees with the Plan Team that a reduction in Allowable Biological Catch from the maximum permissible is justified.” Result from single-species assessment Assessment + ecosystem indicators Ecosystem indicators A multispecies model

KEY IS FOLDING IN TO STOCK ASSESSMENT PROCESS. THIS SYSTEM WORKS WHEN IT IMPACTS A TARGET SPECIES, BUT THERE IS LIMITED MANAGEMENT MANDATE FOR INTERACTIONS. Perhaps Fisheries Ecosystem Plans will create context, avoid crisis mode? low Probability of interaction high low Impact of interaction high Cod eat Atka Increase Atka fishing? Oil spill on rookery Change shipping routes?