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Review of major ecosystem model classes

National Ecosystem Modeling Workshop (NEMoW) August 29-31 2007, NMFS Santa Cruz. Review of major ecosystem model classes. Éva Plagányi Dept. of Maths & Applied Maths, University of Cape Town. With thanks to Doug Butterworth and MARAM.

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Review of major ecosystem model classes

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  1. National Ecosystem Modeling Workshop (NEMoW) August 29-31 2007, NMFS Santa Cruz Review of major ecosystem model classes Éva Plagányi Dept. of Maths & Applied Maths, University of Cape Town With thanks to Doug Butterworth and MARAM 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

  2. 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

  3. 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

  4. 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

  5. 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

  6. Ecosystem ModelsI. Whole ecosystem models

  7. Ecosystem Models- plankton focus (NPZ-fish)

  8. Ecosystem ModelsII. Minimum Realistic Models

  9. Ecosystem ModelsII. Minimum Realistic Models

  10. Ecosystem ModelsII. Minimum Realistic Models cont.

  11. Ecosystem Models- Antarctic Models

  12. Ecosystem ModelsIII. Dynamic System Models

  13. Target Species Predator Catch Catch Ecosystem ModelsIV. Extended Single-Species Models

  14. 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

  15. 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.

  16. 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?

  17. 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

  18. 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

  19. NO ENVIRONMENT ENVIRONMENT SPATIAL STRUCTURE AGE STRUCTURE AGE STRUCTURE Biological interactions described No Technical interaction models MSYPR Murawski 1984 Yes No 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 Predator prey feedback Yes Handles the environment and lower trophic levels No Yes Handles age/size structure Yes No Handles age structure Yes No Handles spatial structure Handles spatial structure Yes Multispecies Production Models e.g. Horbowy 2005 No No Yes Spatial dynamic systems models e.g. ATLANTIS, ERSEM, SEAPODYM Aggregate system models e.g. EwE, SKEBUB, SSEM Dynamic multi-species models BORMICON,GADGET, MRMs,MSVPA& MSFOR, MSM, MULTSPEC, OSMOSE Dynamic systems models e.g. some recent EwE applications Spatial aggregate systems models e.g. ECOSPACE Pg. 4

  20. 30 + 20 10 5 3 2 ATLANTIS EwE ERSEM, INVITRO, OSMOSE NO. OF SPECIES / COMPONENTS GADGET BORMICON, MSVPA, MULTSPEC, ESAM, MRM, SEASTAR, Bioener -getic type MSM, SEAPODYM

  21. MRM, MSVPA, GADGET, SEASTAR, SEAPODYM, IBM, MSM, Bioenergetic EwE, ATLANTIS, INVITRO OSMOSE ERSEM SSEM External forcing Marine mammals, sharks etc TROPHIC LEVEL Clupeoids, demersals etc Zooplankton, filter-feeders Phytoplankton, detritus

  22. 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

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

  24. a) Type I b) Type II PREY KILLED PER PREDATOR PER UNIT TIME c) Type III PREY DENSITY EwE Foraging arena

  25. EXAMPLES: 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

  26. e.g. EwE, GADGET, SEPODYM e.g. GADGET, new EwE

  27. 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

  28. 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

  29. Methods and rules to compute Catch per ssmu Explore uncertainties re model specification and fit to data Simulation testing Use “future” data to compute Catch per ssmu 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 From Rademeyer et al. 2007

  30. 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.

  31. More re Dealing withUncertainty • 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

  32. 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

  33. Spatial Multi-species Operating Model (SMOM) of Krill-Predator Interactions No feedback Feedback 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.

  34. 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

  35. LESS DATA RE MORE SPECIES WHOLE ECO-SYSTEM DATA RE MOVEMENT / DISTRIBUTIONS SPATIAL Data Requirements DETAILED DATA RE FEW SPECIES – USUALLY SIZE/AGE STRUCTURE DATA MRM MORE DATA RE MORE SPECIES e.g. ADDING AGE STRUCTURE ENVIRONMENT, ECONOMIC, SOCIAL, FISHING FLEET, ANTHROPOGENIC

  36. 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

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