# Presentation: 066108

## Review of major ecosystem model classes

- Éva Plagányi
- Dept. of Maths & Applied Maths, University of Cape Town

*Reference:* Plagányi 2007. Models for an Ecosystem Approach to Fisheries. FAO Fisheries Technical paper 477
- Report of Modelling Ecosystem Interactions for Informing an Ecosystem Approach to Fisheries: Best Practices in Ecosystem Modeling, Tivoli, July 3-6, 2007

- National Ecosystem Modeling Workshop (NEMoW)
- August 29-31 2007, NMFS Santa Cruz

*With thanks to Doug Butterworth and MARAM*

## OUTLINE OF TALK

- Ecosystem Model Objectives
- Ecosystem Model Types
- Questions for EAF* Modelling
- Ecosystem Model Classification
- Considerations in Model Building and the Best Practice Approach
- Role of Management Procedures
- Data requirements
- Conclusions

## Ecosystem Models and Management Advice

**Conceptual/understanding:**  of the structure, functioning and interactions of the ecosystem, or sub-system, under consideration. May not be used explicitly in decision-making or scientific advice but forms the **underlying context** for any detailed management planning and decision-making
**Strategic decisions**: linked to **policy goals** and are generally long-range, broadly-based and inherently adaptable
**Tactical decisions:** aimed at the short-term (e.g. next 3-5 years), linked to an operational objective and in the form of a rigid set of instructions e.g. **tactical decision** to change quota

**Ecosystem models generally intended to complement not replace single-species assessment models**

## OUTLINE OF TALK

- Ecosystem Model Objectives
- Ecosystem Model Types
- Questions for EAF* Modelling
- Ecosystem Model Classification
- Considerations in Model Building and the Best Practice Approach
- Role of Management Procedures
- Data requirements
- Conclusions

## Model types

**Whole ecosystem models**: models that attempt to take into account all trophic levels in the ecosystem
**Minimum Realistic Models (MRM):** limited number of species most likely to have important interactions with a target species of interest
**Dynamic System Models (Biophysical)**: represent both bottom-up (physical) and top-down (biological) forces interacting in an ecosystem
**Extensions of single-species assessment models (ESAM)**: expand on current single-species assessment models taking only a few additional inter-specific interactions into account

## Ecosystem ModelsI. Whole ecosystem models 

| MODEL | NAME |
| --- | --- |
| EwE and ECOSPACE | Ecopath with Ecosim |
| ATLANTIS | ATLANTIS |
| IGBEM | Integrated Generic Bay Ecosystem Model  |
| INVITRO | INVITRO |
| GEEM | General Equilibrium Ecosystem Model |

## Ecosystem Models- plankton focus (NPZ-fish) 

| MODEL | NAME |
| --- | --- |
| ERSEM II | European Regional Seas Ecosystem Model |
| SSEM | Shallow Seas Ecological Model |

## Ecosystem ModelsII. Minimum Realistic Models 

| MODEL | NAME |
| --- | --- |
| MRM | Minimally Realistic Models |

## Ecosystem ModelsII. Minimum Realistic Models 

| MODEL | NAME |
| --- | --- |
| GADGET | Globally applicable Area Disaggregated General Ecosystem Toolbox |
| BORMICON | BOReal Migration and CONsumption model |
| MULTSPEC | Multi-species model for the Barents Sea
Simplified version is AGGMULT which is also connected to a ECONMULT - a model describing the economies of the fishing fleet |

## Ecosystem ModelsII. Minimum Realistic Models cont.

| MODEL | NAME |
| --- | --- |
| MSVPA and MSFOR
(and derivatives) | Multi-species Virtual Population Analysis; Multi-species Forecasting Model |
| MSM | Multi-species Statistical Model |

| IBM | Individual-Based Models |
| --- | --- |
| Bioenergetic/allometric  | e.g. Koen-Alonso & Yodzis 2005 |

## Ecosystem Models- Antarctic Models

| MODEL | NAME |
| --- | --- |
| FOOSA | Previously KPFM (Krill- Predator-Fishery Model) |
| SMOM | Spatial Multi-species Operating Model |
| EPOC | Ecosystem Productivity Ocean Climate model |
| Other CCAMLR models e.g. Mori & Butterworth 2005, 2006 |  |

## Ecosystem ModelsIII. Dynamic System Models

| MODEL | NAME |
| --- | --- |
| SEAPODYM | Spatial Ecosystem and Population Dynamics Model |
| OSMOSE | Object-oriented Simulator of Marine ecOSystem Exploitation |
| SystMod | System Model for the Norwegian and Barents Sea |

## Ecosystem ModelsIV. Extended Single-Species Models

| MODEL | NAME |
| --- | --- |
| ESAM | Extended Single-Species Models e.g. Livingston and Methot 1998; Hollowed et al. 2000; Tjelmeland and Lindstrøm  2005  |
| SEASTAR | Stock Estimation with Adjustable Survey observation model and TAg-Return data |

## OUTLINE OF TALK

- Ecosystem Model Objectives
- Ecosystem Model Types
- Questions for EAF* Modelling
- Ecosystem Model Classification
- Considerations in Model Building and the Best Practice Approach
- Role of Management Procedures
- Data requirements
- Conclusions

## Questions for EAF Modelling 

***Issues pertaining to the management of target and related species:***
**Impact of a target species** on other species in the ecosystem?
- Limitations of **single-species-based **assessment
- Targeting of relatively **unexploited **species
- What are the impacts of retained **by-catch**?
- What is the **effect on top predators** of removing the predators themselves and their prey?
- What is the extent of **competition between fisheries and species of concern such as marine mammals,** turtles, **seabirds **and sharks.

## Questions for EAF Modelling 

***Issues pertaining to species:***
- What are the impacts of fishing on **biodiversity**?
- What are the impacts of commencing fishing on a previously **unexploited species** about which little is known.
- Effects of the introduction of **non-native species. **
- What are the impacts of **non-retained by-catch?**

## Questions for EAF Modelling 

***Environmental and unintentional impacts on ecosystems***
**Effects of physical/environmental factors** on the resources on which fisheries depend.
- Changes in **ecosystem state**, e.g. regime shift, change to a less productive/less desirable state.
**Anthropogenic** effects.
- Effects of **habitat modification** e.g. trawling damaging benthic habitats

## Slide 18

## Slide 19

## OUTLINE OF TALK

- Ecosystem Model Objectives
- Ecosystem Model Types
- Questions for EAF* Modelling
- Ecosystem Model Classification
- Considerations in Model Building and the Best Practice Approach
- Role of Management Procedures
- Data requirements
- Conclusions

## Pg. 4

**Biological interactions described**

**Predator prey feedback**

**Handles the environment and lower trophic levels**

**Technical interaction models MSYPR**
- Murawski 1984

**Predators added to single-species models e.g. SEASTAR**
- Gulland 1983; Livingston and Methot 1998; Hollowed *et al.* 2000; Plagányi 2004; Tjelmeland and Lindstrøm  2005

- No

- No

- Yes

- Yes

**Handles age/size structure**

**Handles age structure**

- No

- Yes

**Aggregate system models e.g. EwE, SKEBUB, SSEM**

**Spatial dynamic systems models e.g. ATLANTIS, ERSEM, SEAPODYM**

**Multispecies Production Models **e.g. Horbowy 2005

- Yes

- No

**Dynamic multi-species models BORMICON,** **GADGET, MRMs,** **MSVPA& MSFOR, MSM, MULTSPEC, OSMOSE**

- No

**Handles spatial structure**

- Yes

- No

**Dynamic systems models e.g. some recent EwE applications**

- Yes

**Handles spatial structure**

- No

**Spatial aggregate systems models e.g. ECOSPACE**

- Yes

## Slide 22

## TROPHIC LEVEL

**Phytoplankton, detritus**

**Zooplankton, filter-feeders**

**Clupeoids, demersals etc**

**Marine mammals, sharks etc**

## OUTLINE OF TALK

- Ecosystem Model Objectives
- Ecosystem Model Types
- Questions for EAF* Modelling
- Ecosystem Model Classification
- Considerations in Model Building and the Best Practice Approach
- Role of Management Procedures
- Data requirements
- Conclusions

## Strategical Model Considerations and the Best Practice Approach(based on report from the July 2007 FAO Workshop)

| Consideration in Model Development | Best practice approach : ‘ideal’ practices, i.e. considerations when developing models. Not anticipated that these practices are always achievable or required.  |
| --- | --- |
| Setting up a model |  |
| How many species or groups? | Aggregate based on shared characteristics of the species and omit the least important to keep web tractable |
| Include age, size or stage structure of the species of interest? | Include if there are major shifts over the course of the life history |

## EwE Foraging arena

| Modelling predator-prey interactions: |  |
| --- | --- |
| How much detail in representing predator-prey interactions? | Represent as bi-directional unless it can be motivated sufficiently strongly that it is adequate to include a one-way interaction only in which the predator ration is fixed and changes in prey abundance have no effect on predator populations |
| Which functional response? | Test sensitivity and robustness to alternative functional relationships |

## Slide 27

| Spatial considerations  | Best Practice Approach |
| --- | --- |
| Include spatial structure? | Include where there are major shifts in the location of the species of interest over the course of its life history |
| Include seasonal and temporal structure? | Where there are large differences in the seasonal dynamics in species movement or production |
| Defining boundary conditions | Basing boundaries on biological rather than anthropogenic considerations such as national boundaries |
| Is fishery harvesting more than one stock of a particular species? | Model needs to distinguish such different stocks when the harvesting practice is such as might impact these stocks to different extents; this will necessitate spatially structured models |
| Distinguish different fleets? | If for the same mass of catch, they make substantially different impacts on target and bycatch species or on the habitat |

## Slide 28

| Model components | Best Practice Approach |
| --- | --- |
| Explicitly represent primary productivity and nutrient cycling | May only be necessary when bottom-up forces or lower trophic levels are of key concern. Can be highly informative for some strategic modelling exercises. |
| Include environmental forcing? | Only if it is an absolute requirement for capturing system dynamics. When it is included there must be some means of generating future forcing for use in predictions and closed loop simulations. |

## Slide 29

| Model components | Best Practice Approach |
| --- | --- |
| How to model recruitment? | Recruitment may be included either as an emergent property or as a derived relationship Likely important for tactical and risk analyses, but not strict requirement for strategic models. |

| Mainly emergent recruitment | Mainly derived property |
| --- | --- |
| e.g. EwE, Atlantis, OSMOSE, GADGET | e.g. MSVPA, SEAPODYM, MSM |

## EXAMPLES:

| Model components | Best Practice Approach |
| --- | --- |
| How to model movement? | Testing sensitivity to a range of movement hypotheses. Parameterising movement matrices by fitting to these data. Decision rules check if resultant changes in distribution are sensible |

- OSMOSE: Spatially explicit with fish schools moving to areas with highest potential prey biomass
- GADGET: migration matrices specifying movement between areas; can parameterise by fitting to data
- SEAPODYM: Movement model linked to habitat quality

## Slide 31

| External forcing | Best Practice Approach |
| --- | --- |
| Other process error considerations | Other process error, arising from natural variation in model parameters, needs to be included when variation contributes substantially to uncertainty |
| Other anthropogenic forcing? | Their influence on shallow coastal and estuarine systems should be considered in conceptual models ; should be empirically included |
| Alternative stable states? | Strategic models in particular need to ensure forecasting the consequences of environmental change... |
| Explicitly consider fleet dynamics? | Important to consider if substantial changes to the spatial distribution of fishing may result from, for example, the declaration of an MPA.   |

## Slide 32

| Technical and non-trophic: | Best Practice Approach |
| --- | --- |
| Technical interactions
(e.g. multi-stock fisheries; by-catch) | If the bycaught species are themselves also subject to management, including stock rebuilding, or if the model aims to inform the level of bycatch of a threatened species.  |
| Non-trophic interactions
(e.g. habitat dependency and habitat mediated interactions and processes)  | If a critical determinant of the dynamic of interest (e.g. biomass or abundance of a target group), or if management could be based around this interaction |

## Slide 33

| Dealing with uncertainty | Best Practice Approach |
| --- | --- |
| Should the model be fit to data? | Fitting to data is best practice, and this requires careful specification of likelihoods. |
| Taking account of parameter uncertainty | Include clear statements about uncertainties in model parameters;  Bayesian methods and bootstrapping in ESAM  and MRMs; ..... |
| Model structure uncertainty | Identify alternative qualitative hypotheses for all of the processes considered likely to have an important impact on model outputs |
| What features to include in closed loop simulations? | Evaluation of feedback control harvest strategies should involve simulating the scheme that is likely to be actually used to determine management actions |
| Implementation uncertainty | Implementation uncertainty needs to be linked to consideration of fleet dynamics and is largely driven by, and must be included in, economic considerations... |

## e.g. EwE, GADGET, SEPODYM

| Use and outputs | Best Practice Approach |
| --- | --- |
| Should code be freely available | Documentation and source code must be freely available to allow for review and understanding of the model. Using existing models can be of great help in learning, but careful thought is required when using a pre-existing model so that the tool is not misused |
| Social and economic outputs | Have economic experts collaborating with fisheries ecologists when designing a model implementation of economic factors |
| Ease of modularization | Best is object-oriented design |

- e.g. GADGET, new EwE

## Recent trends in model development

- Modularisation – e.g. substitute different growth, functional response modules
- Fitting to time series data
- Computing constraints – e.g. running on multiple computers in parallel using PVM
- Spatial considerations
- Representation of socio-economic factors and human behavioural drivers
- Multiple sector dynamics and management
- Representation of biodiversity
- Multi-species/ecosystem MSEs

## OUTLINE OF TALK

- Ecosystem Model Objectives
- Ecosystem Model Types
- Questions for EAF* Modelling
- Ecosystem Model Classification
- Considerations in Model Building and the Best Practice Approach
- Role of Management Procedures
- Data requirements
- Conclusions

## Role of OMP/MP/MSE’s(MP = Management procedure; MSE = Management Strategy Evaluation)

**Operating Model to simulate “true dynamics of resource **

**OPERATING MODEL**

**MANAGEMENT PROCEDURE**

- Role of OMP/MP/MSE’s(MP = Management procedure; MSE = Management Strategy Evaluation)

- From Rademeyer *et al.* 2007

## Role of OMP/MP/MSE’s(MP = Management procedure; MSE = Management Strategy Evaluation)

-  Approach involves an evaluation of the implications of alternative combinations of monitoring data, analytical procedures, and decision rules to provide advice on management measures that are robust to inherent uncertainties in all inputs and assumptions used.
-  MSE or MP frameworks are used to identify and model uncertainties and to balance different resource dynamics representations.
-  They provide key examples of formal methods for addressing uncertainty issues.

## More re Dealing with Uncertainty

- Few ecosystem models with applications to practical fisheries management
- Management Procedure testing procedures can use changes in single species parameters (such as carrying capacity *K*) as a surrogate for ecological ecosystem effects e.g. climate change that are difficult to incorporate explicitly in operating models
- Technical ecosystem effects such as bycatch concerns can also be included as Robustness tests in the MP testing process
- These additions constitute a first step towards incorporating ecosystem aspects into practical fisheries management advice
- Multi-species/Ecosystem MPs being developed

*Pg. 52*

## Multi-species/Ecosystem MPs

- ATLANTIS used to evaluate the performance of ecological indicators
- ATLANTIS used to test ecosystem models such as EwE by generating simulated data with known parameters
- South African Pelagic OMP - food requirements of predators such as penguins need to be accounted for in the management process
- CCAMLR: FOOSA and SMOM – spatially explicit multi-species MP frameworks

## Spatial Multi-species Operating Model (SMOM) of Krill-Predator Interactions

- SMOM-predicted change in predator abundance with a) no feedback in spatial catch allocations and b) using a feedback control rule based on a moderate amount monitoring information available for all SSMUs.

- No feedback

- Feedback

## OUTLINE OF TALK

- Ecosystem Model Objectives
- Ecosystem Model Types
- Questions for EAF* Modelling
- Ecosystem Model Classification
- Considerations in Model Building and the Best Practice Approach
- Role of Management Procedures
- Data requirements
- Conclusions

## Data Requirements

- MRM

- DETAILED DATA RE FEW SPECIES – USUALLY SIZE/AGE STRUCTURE DATA

- MORE DATA RE MORE SPECIES e.g. ADDING AGE STRUCTURE

- ENVIRONMENT, ECONOMIC, SOCIAL, FISHING FLEET, ANTHROPOGENIC

## Some conclusions

- A good range of models have been developed for the task of EAF, but greater focus is needed on strengthening these approaches and conducting the necessary data collection and experimentation to underpin confidence in these approaches
- Management decisions will be enhanced by exploring the same issue with different models; confidence in the decisions will increase when the models independently converge on the same management decisions and when uncertainties in the results have been adequately considered.
- MSE/MP approach is best practice
- Strategical modelling will mainly be used to inform and evaluate the Ecosystem Approach to Fisheries, with use in tactical decisions rare