Chesapeake Bay Fisheries Ecosystem Model: Ecopath with Ecosim

1. Chesapeake Bay FisheriesEcosystem Model:Ecopath with Ecosim Howard Townsend NOAA Chesapeake Bay Office

2. Traditional Single-Species Fisheries Model

3. Chesapeake Bay Fisheries Ecosystem Model Trophic Level

4. EwE: An Overview Data Model Research Application Manual Who eats whom? Network analysis Biol.: B, P/B, Q/B, diet. Fleet catches Mass-balance (Ecopath) Ecoranger Academic (ecol. theory) Automatic Functionalresponse, etc. Seaso-nality Sensitivity analysis Pedigree  M.Carlo Economics, social info. Policy exploration Fisheries vs. environment Time-dynamic (Ecosim) Vulnerability, mediation, … Biol. & fishing time series Fisheriesmanagement Tracer- dynamic (Ecotrace) Environmental time series Persistent pollutants Protected area dynamics. Spatial effort allocation Ocean zoning Habitat preference, dispersal, migration etc. Spatial-dynamic (Ecospace) Spatial cost of fishing Nutrient-O2 seagrass, … MPA size (Ecoseed) Prim.prod.(SeaWIFS) Legend: Facultative input Runoff, nutri-ents, depth, … Optional input

5. NMFS, Bering Sea, GoAlaska Greenland Fisheries Inst. EwE project activities Prince William Sound Faroe Fisheries Inst UBC DFO IMR, Bergen Four Fish. Commissions Baltic Sea RP, GEF UoWisconsin DIFRES, Charlottenlund NOAA, Chesapeake Bay NOAA, Chesapeake Bay CEFAS, Lowestoft Trop. Tuna Comm. Black Sea, Turkey NCEAS Venice S Atlantic Fish.Comm. Santander Mote lab La Paz, Mexico G.o Mexico Fish. Inst, Lisboa Azores F.I. West Florida Mote Lab. Six West African Countries Yucatan reefs Jamaica, BVI, … Colombia Trinidad Venezuela = training courses / workshops Charles Darwin Research Station, Galapagos Namibia Abrolhos, Brazil Sao Paulo, Brazil Cape Town Tongoy Gulf, Chile ? Concepcion, Chile Argentina

6. How Can We ‘Test’ Complex Ecosystem Models? • No model fully represents natural dynamics, and hence every model will fail if we ask the right questions. • A ‘good’ model is one that correctly orders a set of policy choices, i.e. makes correct predictions about the relative values of variables that matter to policy choice. • No model can predict the response of every variable to every possible policy choice, unless that model is the system being managed (experimental management approach).

7. How Can We Decide If a Given Model is Likely to Correctly Order a Set of Specific Policy Choices? • Can it reproduce the way the system has responded to similar choices/changes in the past (temporal challenges)? • Can it reproduce spatial patterns over locations where there have been differences similar to those that policies will cause (spatial challenges)? • Does it make credible extrapolations to entirely novel circumstances, (e.g., cultivation/depensation effects)?

8. Ecopath with Ecosim General Info

9. Practical Application of Ecopath with Ecosim: Ecosystem Trophic Modeling • Ecopath is used to organize data (esp. historical) on trophic interactions and population sizes. Has routines for entry of key data on the biology and exploitation of ecosystem groups, and for creating a mass-balance “snapshot” of an ecosystem. • Ecosim builds dynamic predictions by combining the data with foraging arena theory. Provides dynamic simulation of effect changes in fishing or environmental regimes may have on fisheries catches (volume and value) and the abundance of various groups in the ecosystem. • Ecospace for addressing spatial policy questions, esp. marine protected areas. • Ecotrace for exploring ecosystem effects of persistent pollutants

10. Ecopath Master Equation (I) Production= predation + fishery + other mortality + biomass accumulation + net migration

11. Ecopath Master Equation (II) Consumption =production + unassimilated food + respiration

12. Ecopath Mass Balance • The mass balance constraint implemented in the two master equations of serves as filters for mutually incompatible estimates of flow. • All possible information about the components of an ecosystem, of their exploitation and interaction and passes them through the ‘mass balance filter’ of Ecopath. • This result is a likely snapshot of the energetic flows, the biomasses and their utilization. • The more information used in the process and the more reliable the information, the more constrained and realistic the outcome will be.

13. Ecosim • A time-dynamic simulation tool for studying fisheries policy options • Ecosim builds on Ecopath • EwE modeling approach, • Use Ecosim to improve estimates of parameters by fitting to time series data, • Then use Ecosim to project implications of policy and management decisions

14. Ecosim: Forcing Functions

15. Ecosim: Policy Exploration

16. Ecosystem-scale Optimization:Policy Objectives • Maximize fisheries profit • Maximize social benefits • Maximize mandated rebuilding • Maximize ecosystem ‘health’ Evaluate the fleet configuration and effort levels that optimize each of these objectives individually or jointly

17. Fisheries Economics Needs for Ecosystem-scale Optimization ●“Fleet” info (commercial and recreational) ● Landings, discards, discard fates - dead fish → detritus or scavengers ● Value of fishery - Market price - Non-market price ● Cost of fishing - Fixed value of operating each gear - Effort-related cost - Sailing-related cost Based on simple bio-economics models

18. Ecospace: Addressing Spatially-based Policy Options • Ecosim builds on Ecopath and Ecosim • First step is to construct an Ecopath model using the constraints offered by mass-balance and thermodynamics to ensure that parameters are compatible and realistic • Next run the model through Ecosim to check its behavior • Then enter habitat-related parameters required for Ecospace

19. Ecospace: Addressing Spatially-based Policy Options • Replicates Ecosim dynamics over spatial grid of ‘homogeneous’ cells; • Links cells through dispersal of organisms and fishing effort movement/allocation; • Incorporates an advection model; • Accounts for spatial variation in productivity and cost of fishing; • Represents habitat ‘preferences’ by differential dispersal, feeding and predation rates.

20. Ecospace: Spatial Model • Links to: • GIS databases for PP, Depth, T, habitat structures,... • FishBase for depth pref., ... • …

21. Ecospace • Projects Spatial Distributions • Illustrates impact of Protected Areas & Habitat changes

22. Ecotrace: Bioaccumulation • Quantifies accumulation of persistent pollutants (or nutrients) through the food web; • Example shows accumulation through the pelagic part of the Northern Benguela system;

23. Chesapeake Bay Fisheries Ecosystem Model Based on Ecopath with Ecosim Current Status

24. Status of Chesapeake Bay Fisheries Ecosystem: Overview • Ecopath module has been completed (v 1.0). • 45 trophic groups • 218 diet links • Ecosim module • “Tuned” to some time series data; over 44 data sets and assessments. • Simulations can be run to explore policy options (i.e., fisheries management plans). • Minimal fisheries economics/effort data, expanding this part of the module is in planning stage. • Ecospace module development is in planning stage. • Ecotrace module development is in planning stage.

25. Ecopath

26. Ecosim: Time Series Fit

29. Ecosim run - Menhaden

30. Chesapeake Bay Fisheries Ecosystem Model Based on Ecopath with Ecosim Future Direction

31. Short-Term Direction • Evaluation/Validation of version 1.0 • Guided by advisory panel • Input from local experts/users • Technical documentation review & publication • Application • FEP/FMP support • Integrate with Water Quality model (and other efforts) • Collaborate with interested researchers

32. Longer-Term Direction • Produce version 2.0 based on advisory panel and experts suggestions for revisions • Develop policy optimization capabilities (needs improved fisheries and economics data in model) • Develop Ecospace module (for spatially-based management, esp. MPAs) • Develop Ecotrace to explore ecosystem effects of persistent pollutants

33. Howard.Townsend@noaa.gov