North Pacific Marine Science Organization

PICES Press Vol. 22, No. 2

OSM Workshop on an “Ecosystem projection model inter-comparison andassessment of climate change impacts on global fish and fisheries”
By Anne B. Hollowed, Kirstin Holsman and Kerim Aydin
Introduction

science community and the global climate modelingcommunity interface their models and exchange data.

Climate change is a global issue affecting marine
ecosystems and species that span multiple internationalboundaries, and is one of the most universal challenges
facing fisheries scientists and managers around the world.
To address these challenges scientists have developedmodeling approaches and management tools to project
future impacts.
This task mandates international
collaboration to develop approaches that can be
implemented across multiple, large marine ecosystems
worldwide. Keeping pace with a rapidly changing climate
also requires fisheries management tools that canaccurately and efficiently inform best solutions in an
uncertain future and evaluate tradeoffs associated withalternative
carbonmanagement
strategies,
yet
implementation of such management lags behind climatedriven changes to species and ecosystems. As part of the
on-going activities of the PICES/ICES Section on Climate
Change Effects on Marine Ecosystems (S-CCME, also
known as the Strategic Initiative on Climate Change
Effects on Marine Ecosystems), Anne B. Hollowed (AFSC
NOAA), Kerim Aydin (AFSC NOAA), and Kirstin
Holsman (JISAO/AFSC) co-convened a workshop on April
12–13, 2014, at the FUTURE Open Science Meeting(OSM). The workshop was funded by the National Oceanicand Atmospheric Administration (NOAA) National Marine
Fisheries Service (NMFS) as a project within its
International Science Program. Twenty nine scientists,
representing seven nations, participated in the meeting.

The workshop brought together earth system modelers,
oceanographers, fisheries stock assessment scientists, andecosystem modelers to discuss the current and near-term
future status of ESMs and their potential contributions toprojecting climate change impacts on living marine
resources, providing much-needed information forsustainable fisheries management in the future. Increases incomputing power and storage have facilitated refinementsin the spatial and temporal scale of climate models[6] andESMs have been developed that incorporate terrestrial andoceanic biosphere processes. Conceivably, ESM outputs
could be used to project climate change impacts on the
distribution and abundance of phytoplankton andzooplankton in marine systems[7], eliminating the need for
dynamic downscaling of global climate projections toregional circulation models. However, because ESMs may
not appropriately capture important oceanographic features(e.g., regional upwelling zones, coastal eddies, or benthic
processes) the appeal of such a unified, global approach
must be weighed carefully against the advantages ofregionally tailored marine ecosystem modeling frameworks.
Specific objectives for the workshop included:
Obj. 1 Identify the optimal means of combining global
ESMs, high resolution regional modelingframeworks (RMFs), and ecosystem models ofvarying complexity to provide robust assessmentsof climate change impacts on living marine
resources and their habitat.

The goal of this workshop was to discuss options forinterfacing fisheries and ecosystem models with next
generation Earth System Models (ESMs). Several marine
ecosystem modeling approaches have been advanced toproject the impacts of climate-driven changes on marine
ecosystems and to identify sustainable harvest practices forecosystems impacted by climate change[1][2]. Each of theseapproaches has inherent strengths and weaknesses,
depending on which fisheries management questions arebeing considered[3]. Increasingly, fishery and ecosystemmodelers recognize that a global network of models isneeded for a world-wide synthesis of climate change
effects on marine ecosystems and the global food supply. A
necessary first step towards this goal is an assessment of
the relationship between model complexity, efficiency,
predictive skill, and the computational costs of increased
ecological realism in models, which can be used to identify
the suite of candidate models for the global network [4][5].
This assessment requires guidance on how the fisheries

Obj. 2 Coordinate international efforts to assess biologicaland societal impacts of climate-driven changes tofuture marine resources.
The 1½ day workshop (W4) consisted of a mix of oralpresentations and group discussions. On day 1, Anne
Hollowed gave a brief opening address and described the
expectations for the workshop.
She explained thatparticipants would focus on three tasks: (1) review thecurrent state of climate and ecosystem models for eachregion; (2) identify inter- and intra-region comparisons andobjective questions, specifically, identify focal regions/marine systems, available data, and a subset of existingmodels for initial analyses; and (3) identify a list ofcollaborators, individual tasks relative to comparative
analyses phase A or B (see Fig. 1), specific timelines andbenchmarks, and budgetary/funding requirements forcompleting model inter-comparisons.
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Fig. 1 Two-phase framework for model inter-comparisons (order of phases depends on available models and data), using the eastern Bering Sea (AK,USA) as an example. a) Comparative results from coupled regional climate models and nutrient phytoplankton zooplankton models (RCMs/NPZ)
and Earth System Models (ESM); b) intra-regional comparison of model results to identify best models for application in c) inter-regional
comparisons. Proposed regional models are for illustrative purposes only and will depend on existing models for each region. E2E: end-to-end
models; EWE: Ecopath with Ecosim; MSM: multi-species stock assessment; SS: single-species stock assessment.

Task 1 was accomplished through 16 oral presentations
during the first day. The first four speakers discussed
existing work on global climate models and earth systemmodels. The spatial distribution of global climate models
and earth system models varies. Charles Stock reviewed
the types of models currently developed or underdevelopment at the Geophysical Fluid Dynamics
Laboratory in the U.S. Enrique Curchitser discussed
ongoing collaborations between Rutgers University and the
National Center for Atmospheric Research (NCAR) andpresented several examples where models developed by theclimate modeling community have been used to projectchanges in habitat quality and quantity (e.g., polar bear
habitat in the Arctic and spatial extent of future coral reef
bleaching). Scientists at Rutgers and NCAR are partnering
to develop high resolution coupled models (the Community
Earth System Model, CESM) of the California Current
ecosystem. Icarus Allen described the United Kingdom
Earth System Modeling Project (UKESM). Members of
this project are developing suites of models at different
spatial and temporal resolutions that will contribute to thesixth Climate Model Intercomparison Project 6 (CMIP6)
effort. Scientists are exploring outcomes from nutrient,
phytoplankton and zooplankton models with different
levels of complexity. The inter-comparison will attempt tohave common computing platforms, common physics,
common forcing, and common initial conditions. New
models with 1/10 degree spatial resolution of the physicalmodels are being tested in the UK. Michio Kawamiya
discussed the status and future of Japanese climate models.
Japanese scientists are testing new models in preparation
for CMIP6 that will include improved spatial resolution(vertical and horizontal) and enhanced complexity of thenutrient, phytoplankton and zooplankton components of themodels. Nesting models at different spatial scales provide
improved ability to resolve fine-scale physical features inwaters off the coast of Japan.
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The next suite of modelers presented results of efforts toforce regional marine ecosystem models with boundary
conditions from climate models. Beth Fulton described theon-going research in Australia to project the implications ofdecadal variability and climate change on marine
ecosystems. Australian modelers are also striving to
improve the biological realism and spatial resolution ofmodels. She introduced an existing effort to develop a Fish
Model Intercomparison (FISH-MIP) and an Intersectoral
Impact Model Intercomparison (ISI-MIP).
Workshopparticipants recognized that the goals of FISH-MIP and
ISI-MIP are similar to S-CCME and therefore, participants
will pursue possible future collaborations with these groups.
Michael Foreman provided an overview of the current
status and future plans for ocean ecosystem modeling in
Canada. He noted that efforts are underway to improve thespatial resolution and biological realism of the ocean
models. Recent retrospective comparisons showed thatcurrent regional circulation models were not reproducing
offshore upwelling and downwelling winds and seasonaltransitions correctly so additional work is needed. In
addition, Canadian scientists are developing a highresolution regional model for the high Arctic. Al Hermann
discussed a regional ocean model for the southeastern
Bering Sea that was first developed as part of the GLOBEC
program and has been improved as part of the BESTBSIERP Bering Sea Project. This model reproduces
known physical features with reasonable accuracy andpreliminary projections through 2040 are now available foruse in fisheries models.
Afternoon presenters continued to discuss the status ofregional ocean model experiments. Shin-ichi Ito noted thatseveral models have been developed to project climate
impacts on Japanese fish distribution and abundance. The
complexity of the nutrient-phytoplankton-zooplankton
components of these models differed substantially.
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Projections through 2100 are available for some species(e.g., Pacific saury and sardine).
William Cheung
presented a global assessment of the catch potential offisheries in the future based on available climate model
outputs. Kirstin Holsman gave a talk on behalf of Kerim
Aydin who was unable to attend the meeting. Aydin’smodel extends the coupled bio-physical model describedby Hermann to include fish and fishers. The model tracks
local environmental conditions, and fish movement
emerges as a property of energetic demands, preyavailability and predation. Retrospective runs of the model
are able to reproduce the general spatial pattern of key
ecosystem components. Projections should be available
within the next 6 months. Melissa Haltuch and Kirstin
Holsman provided an overview of available methods for
projecting future abundance of key species using climateenhanced single species or multispecies models. Using
approaches similar to Cheung’s dynamic bioclimatic
window approach, Elliott Hazen estimated the impact of
future climate change on the availability of suitable habitatfor several top predators. Pheobe Woodworth-Jencoats
compared projections based on an ecosystem model(Ecopath with Ecosim) and a size spectrum modelingapproach. She found similarities in model outputs at lower
trophic levels but important differences between the twomodeling approaches for larger predators. This finding
provided insight into the range of possible projected future
outcomes. The last speaker of the day was Nicholas Bond
who discussed a relatively new effort to develop short-term
now-casts of climate. These now-casts can be utilized toestimate uncertainty in short-term model projections.

tropic level responses to climate will be derived fromdifferent scenarios regarding regional ocean conditions. To
the extent practicable, investigators will strive to utilize acommon suite of representative concentration pathways(RCPs) and a common suite of GCMs (Global Climate
Models) or ESMs. However, the methods used to downscalethese global boundary conditions to derive regional ocean
conditions will differ between modeling approaches. Thus,
disparate projected impacts of climate change on higher
trophic levels will partially reflect different mechanisms
incorporated into the models utilized by the modeling teams.
We anticipate that the models will span a wide range of
mechanistic complexity ranging from minimally realistic
approaches to fully coupled end-to-end ecosystem models(Fig. 1). Thus, our proposed experiment will not represent atrue model inter-comparison, wherein the conditions are held
constant to the extent practicable and the structural aspects ofthe model are evaluated. The comparison will be anevaluation of the projected higher trophic level responses toregional ecosystems change caused by a common suite ofclimate forcing scenarios.
The participants discussed a variety of issues related toevaluating model performance. They considered theapproach often used in the stock assessment community,
where analysts develop a simulated system with known
properties and then evaluate their model’s ability tocorrectly identify the properties of the system. In thecontext of the proposed experiment, analysts would have todevelop a simulated ocean and lower trophic level systemwith known properties as a test-bed for evaluating model
performance. While this is a useful idea, the feasibility ofanalysts developing a simulated ocean was deemed too
difficult at this time. The group recommended that themodeling framework should include retrospective runs andshort-term predictions as potential diagnostics on model
performance and agreed that the goal of this experiment
was not to judge the models but to compare the projectedscenarios of higher trophic level response across a range ofmodels.

Discussion
In most regions increases in computing power and storage
have facilitated refinements in the spatial and temporalscale of climate models[6], and ESMs have been developedthat incorporate terrestrial and oceanic biosphere processes.
Conceivably, ESM outputs could be used to projectclimate change impacts on the distribution and abundanceof phytoplankton and zooplankton in marine systems[7],eliminating the need for dynamic downscaling of global
climate projections to regional circulation models.
However, because ESMs do not yet appropriately capture
important small-scale oceanographic features (e.g., regional
upwelling zones, coastal eddies, or benthic processes), in
the near-term the use of ESMs in a unified, global approachshould (minimally) be coupled with regionally-tailoredmarine ecosystem modeling frameworks.

The group recognized that defining the framework to
conduct this experiment is a very high priority as it sets thestage for each of the modeling teams.
Workshopparticipants will work off-line to develop this framework.
Details of the modeling framework can be discussed during
the S-CCME meetings at ICES’ Annual Science
Conference and at PICES-2014. The group will propose aworkshop to be held in 2015 to re-convene the group to
finalize the framework.

Definitions

Results of a subsequent workshop (see the workshop on“Climate change and ecosystem-based management ofliving marine resources”) provided substantial evidence
that assumptions regarding the response of fishers tochanges in the distribution and abundance of target species
are important and must be incorporated into the frameworkof the experiment. Participants in that workshop recommended

The workshop participants held a lengthy discussion
regarding terminology for this experiment. Our experiment
differs substantially from the Coupled Model Intercomparison Phase 5 used to support the most recent
Intergovernmental Panel on Climate Change (IPCC)
Assessment Report 5. In our experiment, estimates of higher
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North Pacific Marine Science Organizationthat a range of possible fisher responses should beconsidered and thus, the framework for the proposed upper
trophic level projection experiment should also describe
how to treat this issue.

conducted using projections from multiple GCMs on asingle model[8] and one GCM using multiple biologicalmodels[9], showing the potential benefits of criticallyexamining the outputs of biological models withstructural differences.

Discussion questions

The group recommended that the proposed PICES and
ICES initiative to compare projections of future fish andfisheries using different models could contribute to the
FISH-MIP effort.

1. Are ESMs ready to be implemented for use in forcing
regional ecosystem models?
The group agreed that the current practice of using ocean
and atmospheric conditions derived from GCMs can beextended to utilize outputs from ESMs. Between now and
2021, the spatial resolution of global climate models(GCMs) and ESMs are likely to be reduced to 0.25–0.1
degree. Initial runs of ESMs at 0.1 degree resolution reveal
the models are capable of resolving finer-scale ocean
current features, including eddies and upwelling.
Atmospheric and physical features derived from thesemodels can continue to be used as boundary conditions forregional ocean circulation models. There is wide diversityof opinion whether, or how, nutrient, phytoplankton andzooplankton outputs from ESMs should be used asboundary conditions for regional models. There arepresently no biological feedbacks between the regionalmodels and ESMs.

2. Do existing higher trophic level models use a common
set of the most recent IPCC projections?
Yes and No. While regional teams are using forcing frommodels that have implemented the IPCC emissions
scenarios, they do not all use the same specific (orensemble) GCM or ESM for downscaling RCMs.
Regional ocean circulation modelers often work withmodeling teams in closest proximity to their laboratories.
There are several advantages to this including ease ofaccess to experts for discussions and a general sense of
comfort that the ESM modeling teams are familiar with thelocal physical and environmental features of the region. In
a few cases, regional modeling teams have evaluated GCM
or ESM modeling performance relative to reproducing
important features of a regional ocean. Model selection isbased on performance. For example the Bering Sea
modeling team used the MIROC, CGCM3 and the ECHOG
models. Likewise, the Japanese regional modeling teams
plan to work with modeling teams from the GeophysicalFluid Dynamics Laboratory and the Hadley Center as wellas their local modeling nodes.

Some outputs from climate models are available to thescientific community. However, the temporal resolution of theoutput from some models is coarse and information fromvertical layers is not always available. The regional modelingcommunity should develop a request of key outputs withconsistent spatial and temporal resolutions needed from global
models to adequately force regional models.

The regional modeling teams had a mixed track record withrespect to access and utilization of the most current version
of GCM and ESM models. In several regions the regional
ocean circulation models were being forced with models
developed for AR4 rather than the more recent CMIP5
models. This time-lag needs to be addressed to ensure that
regional ocean model projections are based on the best
available science.

The group noted that several organizations around theglobe have initiated model inter-comparison projects
including:a) The Coupled Model Intercomparison Project Phase 5that formed the basis for the most recent IPCC report;b) The Arctic Model Intercomparison Project;c) The Geoengineering Model Intercomparison Project;d) The Atmospheric Model Intercomparison Project;e) The Carbon–Land model Intercomparison Project;f) The Inter-Sectoral Impact Model Intercomparison
Project (ISI–MIP) which has a sub-component dealing
with marine ecosystems and fisheries (FISH-MIP);g) In 2009, PICES initiated a Marine Ecosystem Model
Intercomparison Project (MEMIP) to examine regional
zooplankton productivity. Extensions of this effort
could contribute to the proposed project focused onfish and fisheries;h) The international MARine Ecosystem Model Intercomparison Project (MAREMIP), which is an ecosystemmodel inter-comparison focusing on hindcasting phytoplankton concentrations as measured by ocean color;i) At the same time as these formal inter-comparison
projects, biological ensemble modeling has been
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3. How should IPCC scenarios be selected (e.g., a specificemission scenario, multiple, etc.)?
Multiple model scenarios are needed to reflect the fullrange of possible future conditions. As noted above, aframework for implementing multi-model higher trophic
level projections will be needed. Time did not permit a full
discussion of this framework.
4. Is (or will) the quality and spatial resolution ofphytoplankton and zooplankton output from ESMs be of
sufficient quality to use as boundary conditions for regionalmodels or as indices for stock projection models?
Unclear. The methodology for coupling biological responses
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PICES Press Vol. 22, No. 2derived from ESMs and regional models has not been fully
developed. A few starting steps have been taken, and thesemake clear that dealing with differences in scale and theresolution of processes in the different models raises scientificissues that need careful handling to avoid the introduction of
artifacts when shifting from one scale to another.

the plankton communities and fish communities (via larval,
juvenile fish age classes and planktivorous species). Many
subtle features of ecosystem evolution are currently missed
and a review of what works where and why would be avaluable exercise, though it may be contingent on the original
motivation for the development of the initial models.

5. What is the state of coupled RCMs/NPZ models?

8. What are the strengths and weakness of simplifying
assumptions for higher trophic level projection?

See Workshop 4 presentations. Multiple regions have begun
or are already using coupled RCMs/NPZ models.

While individual modeling teams have a strong
appreciation of the shortcomings of their own model
representations, they are not well known outside theseexpert user groups. This is, in part, because it would be asignificant undertaking to document these features. The
proposed intermodel comparison, suitably documented,
would be a useful step forward in disseminating thisinformation in a tangible and tractable way.

6. How sensitive are NPZ models to structural assumptions(i.e., boxes)? Should we try to standardize this across regions?
Models are sensitive to their formulations, but it would not
be advisable to insist upon a common modeling platform to
be used universally, as system-specific idiosyncrasies are
required for making robust projections of the dynamics ofdifferent ecosystems. Trying to develop and implement auniversal model would likely require resources and data
sets in excess of what is currently available.

General timelines April 2014: Workshop 1 at the FUTURE Open Science
Meeting, Hawaii; May–December 2014: Design a framework for comparing
within region multi-model projections; March 2015: Workshop 2 to be held in 2015 (Proposals
to be submitted to ICES, PICES and NOAA);
 2015–2016: Complete Phase 1 comparison of multimodel projections for selected regions; Summer 2016: Submit (Phase 1) results to target journal;
 March 2016: Workshop 3 – review frameworks forcomparing between region multi-model projections forselected species groups;
 2016–2017: Complete Phase 2 comparison of region
multi-model projections for selected species; 2019: submit Phase 2 results to target journal;
 December 2020: Published results for use in next IPCC
assessment.

7. What are the most confident outputs from NPZ andecosystem models (e.g., biomass, abundance, shifts indistribution, upper trophic consumers or lower trophic
level biota [e.g., phyto- or zooplankton])?
While there is agreement that the general patterns produced
by NPZ models are capturing system dynamics, the absolutevalues remain uncertain. Zooplankton dynamics are perhaps
the weakest terms at present, with phytoplankton much morereliable. This is, in part, because of how the zooplankton are
currently represented, and also because there are significant
gaps in available data, which become increasingly spatiallyand seasonally heterogeneous with higher trophic levels,
particularly in key processes such as the partitioning ofmortality across different sources of natural mortality. This isimportant because zooplankton are a key trophic link between

See Dr. Anne Hollowed’s bio in the previous article.
Dr. Kirstin Holsman (kirstin.holsman@noaa.gov) is a research scientist with the University of Washington Joint Institute for the Study of the
Atmosphere and Ocean. In collaboration with colleagues at the Alaska Fisheries Science Center (NOAA Fisheries), her current work is focusedon developing quantitative methods for ecosystem-based approaches to management and methods to assess and manage for climate-change
impacts on fish and fisheries. In particular, her research includes climate specific multi-species stock-assessment models for the Bering Sea (AK,USA), Integrated Ecosystem Assessments, bioenergetics and food-web models, and field studies of multi-trophic effects of fishery andaquaculture interactions with marine and estuarine ecosystems.
Dr. Kerim Aydin (Kerim.Aydin@noaa.gov) is the program leader of the Resource Ecology and Ecosystem Modeling Program at the Alaska
Fisheries Science Center. His current research is focused on modeling predator/prey interactions, both from an individual behavioral standpointand from a population (food web model).

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