Modeling at AFSC

Modeling at AFSCModeling at AFSCModeling at AFSCModeling at AFSC

• Kerim Aydin, Sarah Gaichas, John Heifetz, Sarah Kerim Aydin, Sarah Gaichas, John Heifetz, Sarah Hinckley, James Ianelli, Pat Livingston, Bern Megrey, Hinckley, James Ianelli, Pat Livingston, Bern Megrey, Jesus Jurado-Molina, Michael Dalton, Ivonne Ortiz, and Jesus Jurado-Molina, Michael Dalton, Ivonne Ortiz, and Buck StockhausenBuck Stockhausen

• Subset shown in talk: see abstracts for full listSubset shown in talk: see abstracts for full list

Two major scales of Two major scales of modelingmodelingTwo major scales of Two major scales of modelingmodeling• Long-term (50+year) predictionsLong-term (50+year) predictions

– Driven by Climate Change predictions: LOSS OF SEA ICE Driven by Climate Change predictions: LOSS OF SEA ICE and OCEAN ACIDIFICATION: Primarily Biophysical->fish and OCEAN ACIDIFICATION: Primarily Biophysical->fish models (bottom-up)models (bottom-up)

• Interface with current managementInterface with current management– Folding currently operational models in with the stock Folding currently operational models in with the stock

assessment and Council processes: MRM and ecosystem assessment and Council processes: MRM and ecosystem modelsmodels

Feely et al. 2004. Impact of anthropogenic CO2 on the CaCO3 in the oceans. Science 305: 362-366.

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 SockeyeBritish Columbia Sockeye

Central Alaskan Pink Japanese 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 Larvae have behavior!behavior!

preferred night timedepth range

preferred daytimedepth range

+ Growth, Mortality

DisMELS: Dispersal Modeling for Early Life DisMELS: Dispersal Modeling for Early Life Stages (Stockhausen)Stages (Stockhausen)

(A. Hermann)

ROMS 3D Hydrodynamic Model Output

IBM forEarly Life History

Stages

EggStage 1

LarvalStage 1

EggStage N

LarvalStage M

DisMELS and ROMSDisMELS and ROMS(one of multiple (one of multiple

efforts interfacing efforts interfacing with ROMS)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

HouseholdsCapital & Labor

Consumption & Savings

Final Goods ProducersConsumptionInvestment

GovernmentExports & Imports

Intermediate goods producersAgricultureFisheriesForestsEnergy

Everything Else (ETE)

K & L C & I

E & M

ISAMEwE/

Ecosense

SeafoodCO2,GHGs

Climate

Integration with Integration with managementmanagementIntegration with Integration with managementmanagement

• 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 Recent declines in most valuable fishery, the walleye pollock (CASE STUDY for both strategic and tactical integration)integration)

• Steller Sea Lions Steller Sea Lions

• Aleutian Islands Fisheries Ecosystem PlanAleutian Islands Fisheries Ecosystem Plan

““This” This” generationgeneration

• Multispecies Bycatch Model: Multispecies Bycatch Model: – Technical (Gear) interactions, Technical (Gear) interactions,

age structured with detailed age structured with detailed management scenarios, no management scenarios, no predator/prey linkspredator/prey links

• MSVPA/MSFOR/MSM/MAMAKMSVPA/MSFOR/MSM/MAMAK– Multispecies age structured Multispecies age structured

predator/prey for 7 target predator/prey for 7 target species, adds explicit predation species, adds explicit predation effects to recruitment hindcastseffects to recruitment hindcasts

• Ecopath/EcosimEcopath/Ecosim– Includes non-target and Includes non-target and

protected species dynamics, protected species dynamics, gear, limited age structure gear, limited age structure (primarily biomass dynamics)(primarily biomass dynamics)

• An “operational ensemble?”An “operational ensemble?”

Multispecies & multiMultispecies & multi--fi sheries managementfisheries management

Fisheries

Multiple species/ stocks

Multispecies & multiMultispecies & multi--fi sheries managementfisheries management

Fisheries

Multiple species/ stocks

walleye pollock

Pacific cod

Greenland turbot

yellowfin sole

rock sole

arrowtooth flounder

Pacific herring

northern fur seal

PreyPredator - prey

Other predators

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>>M2 F,M2 M2>>F

High Single-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.

Medium Single-species management of fully exploited species.

Concern over multispecies implications of fishery.

Partially utilized species within a food web, some concern over fishery.

Low Single-species management of species with low exploitation.

Low concern. Low concern.

(Fishing+Predation)/ Production

F>>M2 F,M2 M2>>F









F>>M2 F,M2 M2>>F









Broad strategic scoping leads to MRMs, and PARAMETER ESTIMATION/VALIDATION MSVPA and Multispecies Statistical Model

Walleye pollock

Pacific codFishery

Arrowtooth flounder

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

1975 1980 1985 1990 1995 2000 2005 2010

Year

Pre

dat

ion

mo

rtal

ity

(yea

r-1)

MSVPA MSM

Comparison of age-2 pollock predation mortality

MSVPA

0

0.01

0.02

0.03

0.04

0.05

0.06

0.07

0 0.05 0.1 0.15 0.2 0.25

Predation mortality

Po

ste

rio

r d

istr

ibu

tio

n

Age-2

(Ianelli and Jurado-Molina)

MCMC integrated profile of M

MAMAK: Aleutian fisheries 1979-2003 (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 biomassPredation “off”: black dashesPredation “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

0.1

1

10

100

0.00001 0.0001 0.001 0.01 0.1 1 10 100 1000

Shrimp Biomass (t/km2), log scale

Juv.

Po

llo

ck n

atu

ral

mo

rtal

ity

(1/y

ear)

, lo

g s

cale

0.1

1

10

100

0.000001 0.00001 0.0001 0.001 0.01 0.1 1 10 100

Arrowtooth Biomass (t/km2), log scale

Juv.

Po

llo

ck n

atu

ral

mo

rtal

ity

(1/y

ear)

, lo

g s

cale

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

Impa

ct o

f in

tera

ctio

n

hi

gh

Cod eat

Atka

Increase Atka

fishing?

Oil spill on rookery

Change shipping routes?

Documents

Modeling at AFSC