Ecopath, Ecosim, and Ecopath, Ecosim, and fisheries fisheries

management??management??

Belief in model

Ins

igh

ts g

ain

ed

“Non believer” “Believer”

“Realist”

Some terminologySome terminology

ECOPATH - Builds a food webECOPATH - Builds a food web ECOSIM - ECOSIM - One wayOne way to make this web dynamic to make this web dynamic ECOSPACE - An attempt at spatial modelingECOSPACE - An attempt at spatial modeling

EwE (from www.ecopath.org) is one implementation.EwE (from www.ecopath.org) is one implementation.– Semi-black box Semi-black box – This useful for initial work (data exploration, basic tradeoffs, in This useful for initial work (data exploration, basic tradeoffs, in

other words, ecological priors)other words, ecological priors)– Currently insufficient for extensive “formal confrontation” of Currently insufficient for extensive “formal confrontation” of

models and datamodels and data– Most work here was performed with Ecosim algorithms, outside Most work here was performed with Ecosim algorithms, outside

of the black boxof the black box

Model distributionModel distribution

EwE (from www.ecopath.org) is one EwE (from www.ecopath.org) is one implementation.implementation.

– Semi-black box Semi-black box – This is v. powerful for some uses (data exploration, This is v. powerful for some uses (data exploration,

tradeoffs)tradeoffs)– Currently insufficient for extensive “formal Currently insufficient for extensive “formal

confrontation” of models and dataconfrontation” of models and data

Our aim is to build in both of these areas Our aim is to build in both of these areas (current use and better tools).(current use and better tools).

In the beginning was In the beginning was DYNUMES...DYNUMES...

– ECOPATH ECOPATH – Began with Polovina 1984, updated by Christensen and Pauly Began with Polovina 1984, updated by Christensen and Pauly

(early 1990s) - statistics added until current (year 2000) version. (early 1990s) - statistics added until current (year 2000) version. But basic equations are unchanged (and well-examined) for over But basic equations are unchanged (and well-examined) for over 10 years.10 years.

– ECOSIM (and ECOSPACE)ECOSIM (and ECOSPACE)– Recent work to make a food web dynamic, theory and practice Recent work to make a food web dynamic, theory and practice

new (some is un-reviewed with ad-hoc corrections). new (some is un-reviewed with ad-hoc corrections).

– Unified (open?) format is strength Unified (open?) format is strength

Why try to use the “whole” food web in Why try to use the “whole” food web in a predictive model?a predictive model?

Eastern Eastern Bering SeaBering Sea

What is the use of a mass-What is the use of a mass-balance ecosystem model, balance ecosystem model,

anyway?anyway?

First and foremost, stock-scale First and foremost, stock-scale (usually annual) data integration, (usually annual) data integration, hypothesis exploration.hypothesis exploration.

Use may be a qualitative Use may be a qualitative communication of trade-communication of trade-

offsoffs

This model This model maymay do whatever you want, there are do whatever you want, there are good and bad examples. good and bad examples.

But what you have to do to get what you want may But what you have to do to get what you want may be very instructive.be very instructive.

Don’tDon’t mistake the explorations for yield predictions. mistake the explorations for yield predictions.

Not a single species replacement: used in Not a single species replacement: used in conjunctionconjunction

First steps to “large marine” scale predator/prey managementFirst steps to “large marine” scale predator/prey management– Climate shifts vs. noise (pulses) vs. interspecies vs. fishing.Climate shifts vs. noise (pulses) vs. interspecies vs. fishing.– The secret life of metrics (total system biomass? T.L. of catch?)The secret life of metrics (total system biomass? T.L. of catch?)– Ecological theory.Ecological theory.– Sensitive (but mysterious) species issues.Sensitive (but mysterious) species issues.

Predator culling is a real issuePredator culling is a real issue– current back-of-the-envelope approaches may be worse (these models current back-of-the-envelope approaches may be worse (these models

show culling may or may not work). But models are the only way...show culling may or may not work). But models are the only way...

Data qualityData quality– Reconciliation, sensitivity, and targeting new data.Reconciliation, sensitivity, and targeting new data.– Will more data help (the predator culling issue).Will more data help (the predator culling issue).

Radical re-design of “working” an ecosystem.Radical re-design of “working” an ecosystem.– Command, control, or along for the ride?Command, control, or along for the ride?

CriticismsCriticisms

– It’s a It’s a modelmodel So is everythingSo is everything

CriticismsCriticisms

– It’s a model It’s a model on the wrong scaleon the wrong scale Stocks, not processesStocks, not processes

CriticismsCriticisms

– It’s a It’s a biomass dynamicsbiomass dynamics model model It’s one tool among many.It’s one tool among many.

Biomass dynamics are poor Biomass dynamics are poor dynamics???dynamics???

It’s our conceptual basis (MSY).It’s our conceptual basis (MSY). Replace one set of assumption (constant Ms) with another Replace one set of assumption (constant Ms) with another

(simplified age structure).(simplified age structure). ““A A balancebalance between necessary complexity across species.” between necessary complexity across species.” A complement to age-structured (single or multi-species) A complement to age-structured (single or multi-species)

models.models.

The “why won’t our hypothesis work with simple The “why won’t our hypothesis work with simple models” challenge.models” challenge.

Where it breaks down, detail may be added (delay Where it breaks down, detail may be added (delay difference etc.). difference etc.).

Comparison Comparison (deterministic (deterministic

forecast)forecast) Single speciesSingle species– M(age)M(age) fixed, estimated fixed, estimated– Growth/BioGrowth/Bio = fixed or DD at age = fixed or DD at age– Recruit(0)Recruit(0) = f(N, B) = f(N, B)– Partial recruitment to fishery, spawning Partial recruitment to fishery, spawning – climate, other spp added through external parametersclimate, other spp added through external parameters

MSFORMSFOR– M(age)M(age) = f(pred(age), prey(age)) = f(pred(age), prey(age))– Growth/BioGrowth/Bio fixed or DD at age fixed or DD at age– Recruit(0)Recruit(0) = f(N,B) = f(N,B)– Partial recruitment to fishery, spawning, ontogenetic (given data)Partial recruitment to fishery, spawning, ontogenetic (given data)– Climate externalClimate external

EcosimEcosim– One or two pools -2 pools have internal delay structureOne or two pools -2 pools have internal delay structure– M(juv,adu)M(juv,adu) = f(Bpred,Bprey) = f(Bpred,Bprey)– Growth/Bio(juv/adu)Growth/Bio(juv/adu) = f(Bpred,B prey) = f(Bpred,B prey)– Recruit(0)Recruit(0) = f(Bpred, Bprey) = f(Bpred, Bprey)– (If one pool, recruit is fixed prop. Cost of growth)(If one pool, recruit is fixed prop. Cost of growth)– Knife-edged recruit to fishery, spawning, ontogenetic, climate still externalKnife-edged recruit to fishery, spawning, ontogenetic, climate still external

Shapes capture some age structure (reduce parameters)

CriticismsCriticisms

– It’s an It’s an equilibriumequilibrium biomass dynamics model biomass dynamics model

Mass-balance is a perturbable starting pointMass-balance is a perturbable starting point– Mass-balance is not an equilibrium assumption.Mass-balance is not an equilibrium assumption.– (First, a look at the mass balance process).(First, a look at the mass balance process).

In moving from Ecopath to Ecosim, an equilibrium In moving from Ecopath to Ecosim, an equilibrium is built.is built.

– This confrontation is the major work to discuss.This confrontation is the major work to discuss.– (Overcompensatory functional responses, etc.).(Overcompensatory functional responses, etc.).

A single trophic A single trophic relationshiprelationship

Bi Bj

[P/B]j*Bj + Ii +Ei - j[Q/B]j*DCj*Bj - Other loss

= 0 (Mass Balance)

[Q/B]j*DCij*Bj [P/B]j*Bj

Solving each unknownSolving each unknown

– [P/B]i*Bi*EEi = F*Bi [P/B]i*Bi*EEi = F*Bi [[j[Q/B]j*DCj*Bj j[Q/B]j*DCj*Bj ]]ii P/B, EE unknown:P/B, EE unknown:

– top down (demand) solution.top down (demand) solution. Q/B unknown, B unknown:Q/B unknown, B unknown:

– top down / one prey itemtop down / one prey item

– Catch (F*B) should be known.Catch (F*B) should be known.– Diet composition must be known.Diet composition must be known.– Generalized inverse for over- or under-Generalized inverse for over- or under-

determined models.determined models.

Sources of dissipation Sources of dissipation

(1-G) (1-EE)

(Q/B) (P/B)

Sources of dissipation Sources of dissipation (EE is the key).(EE is the key).

EE is what you don’t know about the system.EE is what you don’t know about the system.– May include known time trends in the accounting May include known time trends in the accounting

(BA: biomass accumulation).(BA: biomass accumulation).

(1-G) (1-EE)

(Q/B) (P/B)

Q*G*EE

Mass-balance (Ecopath step) reconciles Mass-balance (Ecopath step) reconciles data - not in itself an equilibriumdata - not in itself an equilibrium

Data issuesData issues always a mix of good, bad, and uglyalways a mix of good, bad, and ugly a different way of reconciling conflictsa different way of reconciling conflicts

Combine and compare:Combine and compare: Harvest/stock assessmentsHarvest/stock assessments Diet dataDiet data Bioenergetics/growthBioenergetics/growth Mortality/rate studiesMortality/rate studies Lower trophic level productionLower trophic level production

The (black) art ofThe (black) art ofmodel balancingmodel balancing

Benefit: you start to see the trade-offs Benefit: you start to see the trade-offs (necessary correlations).(necessary correlations).

It’s where you first address data quality.It’s where you first address data quality.– Reconciliation of scales, techniques, and Reconciliation of scales, techniques, and

sources.sources.– ““What must you do to reconcile multiple What must you do to reconcile multiple

single species assessments”single species assessments”

Like the black art of Bayesian priorsLike the black art of Bayesian priors

The equilibrium The equilibrium questionquestion

All models have an equilibrium.All models have an equilibrium.

Ecosim starts there: it’s an Ecopath to Ecosim transition Ecosim starts there: it’s an Ecopath to Ecosim transition issue.issue.

Fast rebound (overcompensation) may be tuned.Fast rebound (overcompensation) may be tuned.

Sensitivity approach may be implemented to fix this Sensitivity approach may be implemented to fix this (spin up approach).(spin up approach).

BP/BQ/BDCEE

CatchBAetc.

(massaccounting)

Bioenergetics

M2GEM0VulF

(no B)

Pop. Rates (Z is key)

Equilibrium built here, perturbed here

Alternate stable states??Alternate stable states??

ECOPATH to ECOSIMECOPATH to ECOSIM

From a zero-dimensional From a zero-dimensional equilibrium state to a zero-equilibrium state to a zero-dimensional dynamic equation:dimensional dynamic equation:

Prey PredatorP/B*Bi

Prey Predatorc(Bi,Bj)

Q/B*Bj

EE

Dynamics of overlap - (one Dynamics of overlap - (one predator one prey)predator one prey)

Bi - Vij Vij

Bj

vijVij

vij (Bi-Vij)aijVijBj

dVij /dt = vij(Bi-Vij) - vijVij - aijVijBj

Assume fast equilibrium for Vij

V

B-V

“It’s cold down there!”

The appearance of The appearance of Density DependenceDensity Dependence

dVdVij ij /dt/dt = v= vijij(B(Bii-V-Vijij) - v) - vijijVVijij - a - aijijVVijijBBj j = 0= 0

VVij ij = v= vijijBBii/(2* v/(2* vijij + a + aijijBBjj))

CCij ij (B(Bii,B,Bjj) = a) = aijijvvijijBBiiBBj j

(2* v(2* vijij + a + aijijBBjj))Predator Biomass

Cij (or Minstant)

Prey biomass

Cij /Bj

Mathematically, halfway Mathematically, halfway between the trickle and the between the trickle and the

vat vat

CCij ij (B(Bii,B,Bjj) = v) = vijijBBi i

( 2v( 2vijij + 1 ) + 1 )

aaijijBBjj

– Integrate limited smaller spatial and temporal dynamics Integrate limited smaller spatial and temporal dynamics (more or less)(more or less)

– Single “vulnerability” parameter X ~ 2v/aBj ratioSingle “vulnerability” parameter X ~ 2v/aBj ratio

AGE STRUCTURE:AGE STRUCTURE: – Possible example: good evidence for this functional response, Possible example: good evidence for this functional response,

both by age (e.g. pollock) and by density-dependence (e.g. both by age (e.g. pollock) and by density-dependence (e.g. halibut).halibut).

One predator, many One predator, many preyprey

Prey switching exists as a complex of 3 variables Prey switching exists as a complex of 3 variables – base diet, vulnerability, feeding time to modify suitabilitiesbase diet, vulnerability, feeding time to modify suitabilities

Captures some age-structure dynamics without the Captures some age-structure dynamics without the age structureage structure

– Basic assumption is that biomass is not independent of Basic assumption is that biomass is not independent of diet, age structure.diet, age structure.

Switch or die?Switch or die?

Invasions/vast changes not captured.Invasions/vast changes not captured.a b

a b

a

ab

bb

bb

ba a

a a

b

bb

bb

bb

b

Age-structure simulationAge-structure simulation

0

1

2

3

4

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

Predator Biomass

Pro

du

ctio

n/B

iom

ass

fro

m e

ach

p

rey

so

urc

eForage FishEuphausiidCopepods

Smaller biomass implies younger age structure through changing relative vulnerability set by ‘v’ parameters.

MSFOR vs. Ecosim?MSFOR vs. Ecosim?

Different sides of the same coinDifferent sides of the same coin Simplify age structure (Ecosim) or simplify Simplify age structure (Ecosim) or simplify

consumption (MSVPA).consumption (MSVPA). MSVPA assumes fixed suitabilities at age.MSVPA assumes fixed suitabilities at age. Ecosim assumes changing suitabilities with Ecosim assumes changing suitabilities with

biomass (and therefore with age and foraging biomass (and therefore with age and foraging combined).combined).

Hybrid methods are quite possible.Hybrid methods are quite possible.

Fishing in EcosimFishing in Ecosim By individual species or gear type By individual species or gear type

– may apply to a species directly, or as an effort may apply to a species directly, or as an effort multiplier to gear.multiplier to gear.

Gear type applies exploitation rate on Gear type applies exploitation rate on multiple species group...bycatch is tied to multiple species group...bycatch is tied to gear effort.gear effort.

Model behaviorModel behavior Top-down (fishing) experiments:Top-down (fishing) experiments:

Apex predators behave as single-species Apex predators behave as single-species models with (over?) compensatory growth of models with (over?) compensatory growth of prey.prey.

Pella-Tomlinson form if prey is fixed.Pella-Tomlinson form if prey is fixed. Cascades appear below apex predators.Cascades appear below apex predators.

Middle and lower trophic level fishing results Middle and lower trophic level fishing results are unpredictable.are unpredictable.

MSY and overcompensation MSY and overcompensation in base scenariosin base scenarios

Phytoplankton Zooplankton Fish

(Aydin 2001; submitted)(Aydin 2001; submitted)

The effect of vulnerability on The effect of vulnerability on MSYMSY

0

1

2

3

4

0 0.2 0.4 0.6 0.8 1

B/Bvirgin(fish)

Catc

h/B

vir

gin

(fis

h) Catch(fish)

Vul-0.10

Vul-0.60

Fmsy=2.5

Fmsy=4.5

Fmsy=12.7

Eq. Fish biomass (prop. of K)

012345678

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1

B/Bvirgin(fish)

B/B

vir

gin

(zo

op

.)

B/Bvirgin(zoop)

Vul-0.10

Vul-0.60

Eq. Fish biomass (prop. of K)

Fish Fish

CatchCatch

ZoopZoop

B/B0B/B0

Phytoplankton Zooplankton Fish

age-structure and age-structure and bioenergeticsbioenergetics

Some basic decisions in the model Some basic decisions in the model need to be revisited in the next need to be revisited in the next generation.generation.– Coordination with MSVPACoordination with MSVPA– Energy partitioningEnergy partitioning– Myers et al.Myers et al.– Bioenergetics decisions. Bioenergetics decisions. – But led to compesation/depensation. But led to compesation/depensation.

MSY and bioenergetic overcompensationMSY and bioenergetic overcompensation

Another Another example: example: passive vs. passive vs. active active metabolism in metabolism in zooplanktonzooplankton

0

0.2

0.4

0.6

0.8

1

0 0.2 0.4 0.6 0.8 1

B/Bvirgin(fish)

Catch(fish)

Case1

Case2

Fmsy=1.2

Fmsy=4.5

Fmsy=0.8

012345678

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1

B/Bvirgin(fish)

B/Bvirgin(zoop)

Case1

Case2

Eq. Fish biomass (prop. of K)

Phytoplankton Zooplankton Fish

Fit to single species?Fit to single species?EBS Pollock

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

0 5 10 15 20 25 30

Biomass (t/km^2)

Pro

du

cti

on

/bio

ma

ss

(g

row

th &

re

cru

it.)

P/B from single speciesP/B fit to vulnerability

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9 1

1.03

1.05

1.08

1.14

1.22

1.37

1.61

2.00

2.65

3.72

5.48

8.39

13.18

21.09

34.12

P/B at reference biomass (27 t/km^2)

Ec

os

im v

uln

era

bility

0

0.01

0.02

0.03

0.04

0.05

0 1 2 3 4 5 6

P. Cod biomass (t/km2)

Fla

thea

d s

ole

mo

rtal

ity

by

P.

cod

(1/

year

)

0

0.01

0.02

0.03

0.04

0.05

0.06

0.07

0.08

0.09

0.1

0.11

0.12

0.13

0.14

0 1 2 3 4 5 6

P. Cod biomass (t/km2)

Wal

leye

po

llock

mo

rtal

ity

by

P.

cod

(1/

year

)

Additional data: Additional data: anomalies in anomalies in consumptionconsumption

– Systematic anomalies in Systematic anomalies in consumption rates?consumption rates?

Food habitsFood habits Predator sizePredator size Prey sizePrey size abundant year classesabundant year classes Age class models Age class models

– Run the model backwards? Too Run the model backwards? Too much noise!much noise!

– Evidence of alternate stable states?Evidence of alternate stable states?

RecruitmentRecruitment– A delay-difference equation with juveniles A delay-difference equation with juveniles

divided into monthly pools:divided into monthly pools: Size vs. age at recruitment tuneableSize vs. age at recruitment tuneable Energy apportionment strategiesEnergy apportionment strategies Individual growth ratesIndividual growth rates

– Knife edge recruitment to fishery, spawning, Knife edge recruitment to fishery, spawning, and ontogenetic switch.and ontogenetic switch.

– Spawning biomass is indirect measure.Spawning biomass is indirect measure.– This is a primary simplification (also for This is a primary simplification (also for

afternoon discussion).afternoon discussion).

Model behaviorModel behavior Bottom-up (forcing) experiments:Bottom-up (forcing) experiments:

Time scale (frequency) is important.Time scale (frequency) is important. Who responds the fastest?Who responds the fastest? Invasions are not predictable.Invasions are not predictable.

Explanations may be dangerousExplanations may be dangerous External (climate) hypotheses must existExternal (climate) hypotheses must exist (EBS climate fitting as case-study: afternoon)(EBS climate fitting as case-study: afternoon) climate image:climate image:

mesoscale and mesoscale and migrationsmigrations

MesoscaleMesoscale Reasonable as single-species models for Reasonable as single-species models for

fishing experimentsfishing experiments Seasonal changes, aggregations on prey Seasonal changes, aggregations on prey

may lead to detectable systematic may lead to detectable systematic changes in foraging parameterschanges in foraging parameters

MigrationsMigrations Model may be damped by “external” food Model may be damped by “external” food

sources. sources.

Needed to make Needed to make ECOSIM rigorousECOSIM rigorous

Many of the problems listed (prey Many of the problems listed (prey switching, etc.) are not specific to switching, etc.) are not specific to Ecosim.Ecosim.

– Basic fitting exists.Basic fitting exists.– Thorough peer-reviewed testing against Thorough peer-reviewed testing against

single-species, MSVPA models.single-species, MSVPA models.– An improved statistical framework.An improved statistical framework.– This is the next major development (come see This is the next major development (come see

the quantitative seminar!).the quantitative seminar!).

First:First: – Vul fitting indicates Vul fitting indicates

low vuls (v<0.05) fits low vuls (v<0.05) fits better (recruitment better (recruitment dominated??)dominated??)

– Kept vuls at 0.3Kept vuls at 0.3

Fitting 1979-2000Fitting 1979-2000

The confrontation: can it be The confrontation: can it be done, what do we learn?done, what do we learn?

Ecopath as priors.Ecopath as priors.

Specification of full-scale Specification of full-scale problem in progress problem in progress (balancing importance (balancing importance and covariance of and covariance of bioenergetics, foraging, bioenergetics, foraging, mortality).mortality).

BP/BQ/BDCEE

CatchBAetc.

(massaccounting)

Bioenergetics

Ecopath as priors to examine correlation using: population and life Ecopath as priors to examine correlation using: population and life history trade-offs, some single-species modelshistory trade-offs, some single-species models

M2GEM0VulF

(no B)

Pop. Rates (Z is key)

Fitting occurs hereFitting occurs here

Meanwhile, culling in Meanwhile, culling in a simple modela simple model

Can we reasonable predict the Can we reasonable predict the results of a removal of the top results of a removal of the top predator?predator?

Groundfish are near MSY:Groundfish are near MSY:– F=MF=M– 80% of M from mammals80% of M from mammals– 15% of M from pred. Fish15% of M from pred. Fish– 5% “unidentified”5% “unidentified”

Can we increase yield (while Can we increase yield (while holding effort constant) by holding effort constant) by removing mammals?removing mammals?

Yes (made to happen)Yes (made to happen)

0.4 0.6 0.8 1 1.2 1.4 1.6

MammalPredator

Predatory Fish

Adu Groundfish

Juv Groundfish

Forage Fish

Zooplankton

Phytoplankton

Detritus

GroundfishCatch

Total Biomass

After 50 years

(Truism: killing an animal will stop it from eating: but where does the energy end up?)

0.4 0.6 0.8 1 1.2 1.4 1.6

MammalPredator

Predatory Fish

Adu Groundfish

Juv Groundfish

Forage Fish

Zooplankton

Phytoplankton

Detritus

GroundfishCatch

Total Biomass

After 50 years

Our confidence?Our confidence?

Perform 1000s of draws, Perform 1000s of draws, allowing start out of allowing start out of equlibrium drawing:equlibrium drawing:

– Diets from uniform ±30%Diets from uniform ±30%

– Vuls from range between Vuls from range between 0.1 and 0.60.1 and 0.6

– All others (P/B, Q/B, All others (P/B, Q/B, passive/active respiration) passive/active respiration) from uniform ±10%from uniform ±10%

Results: often down, not upResults: often down, not up

Mammal vs. predatory fish: fish winsMammal vs. predatory fish: fish wins– Improving diet data unlikely to help this picture.Improving diet data unlikely to help this picture.– Possibility of improving mammals through lower fishing also uncertain.Possibility of improving mammals through lower fishing also uncertain.– Admission: this is a simple, tightly-wired web (vuls tightly wired??).Admission: this is a simple, tightly-wired web (vuls tightly wired??).

What about more complex webs?What about more complex webs? What about climate variability?What about climate variability? What about the unmodeled, inedible predator?What about the unmodeled, inedible predator? WHAT ABOUT PROCESS UNCERTAINTY INCREASE???WHAT ABOUT PROCESS UNCERTAINTY INCREASE???

0

200

400

600

800

1000

1200

0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 2.2 2.4 2.6

Final Value

Fre

qu

en

cy

Mammal Predator

Predatory Fish

Adu Groundfish

Juv Groundfish

Forage Fish

Zooplankton

Phytoplankton

Detritus

Biomass after 50 years/start biomass

Command, control, or Command, control, or along for the ride?along for the ride?

If we can’t predict manipulations (esp. in light of added If we can’t predict manipulations (esp. in light of added climate variability), we should aim/add to our objectives climate variability), we should aim/add to our objectives the minimization of unpredictable cascades, rather than the minimization of unpredictable cascades, rather than the optimization of multispecies yields or specific the optimization of multispecies yields or specific trophic-based rebuilding plans.trophic-based rebuilding plans.

A “healthy” ecosystem (without homeostasis).A “healthy” ecosystem (without homeostasis).

How much did all fish go through “regimes” before we How much did all fish go through “regimes” before we fished them?fished them?

Laundry list 1Laundry list 1

– Model savvy in current usesModel savvy in current uses

Endangered (im)possibilities (restore Endangered (im)possibilities (restore S.S.L.s through prey?)S.S.L.s through prey?)

Climate and causality seeking.Climate and causality seeking. Seeking key/critical species interactions Seeking key/critical species interactions

and uncertainties.and uncertainties. Model behavior and improvement.Model behavior and improvement. Radical rethinking (the impossible MSY Radical rethinking (the impossible MSY

and variability?)and variability?)

Laundry List for management discussion (some Laundry List for management discussion (some may work or may have worked)may work or may have worked)

First steps to “large marine” scale predator/prey managementFirst steps to “large marine” scale predator/prey management– Necessary in a loosely/tightly wired system?Necessary in a loosely/tightly wired system?– Climate shifts vs. noise vs. interspecies vs. fishing.Climate shifts vs. noise vs. interspecies vs. fishing.– The secret life of metrics (total system biomass? T.L. of catch?)The secret life of metrics (total system biomass? T.L. of catch?)– Ecological theory (cultivation/depensation).Ecological theory (cultivation/depensation).– Communication of alternatives.Communication of alternatives.– Endangered and HAPC species Issues.Endangered and HAPC species Issues.

Predator culling is a real issuePredator culling is a real issue– current back-of-the-envelope approaches may be worse (these models show current back-of-the-envelope approaches may be worse (these models show

culling may or may not work).culling may or may not work). Data quality issuesData quality issues

– Reconciliation.Reconciliation.– Sensitivity/targeting new data.Sensitivity/targeting new data.

Radical re-design of “working” an ecosystem.Radical re-design of “working” an ecosystem.– Command, control, or along for the ride?Command, control, or along for the ride?