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Frequently Asked Questions about Ecosystem Modeling

Why Does the NOAA Chesapeake Bay Office Support Ecosystem Modeling?

  • This work is part of the NOAA Chesapeake Bay Office’s overall effort to provide science and services in support of ecosystem approaches to management in the Chesapeake, which is mandated by the Magnuson-Stevens Act and the Office’s Congressional authorization.
  • Ecosystem modeling can synthesize information about changes in habitat and land-use practices that influence living resources in the Bay. This type of synthesis is critical to success in restoration of the Bay.
  • It is usually not feasible to monitor all indicators of the functionality and "health" of an ecosystem directly, but models enable scientists to extrapolate some indicators from measurable variables.
  • Models enable projection. Projected changes in indicators help to identify needs for adjusting management plans and policy decisions.
  • Management plans rest on implicit assumptions about causal relationships between plans and desired outcomes. Mathematical models necessitate formalization of those assumptions and provide structure for organizing relationships. This formalization ensures objectivity and transparency for stakeholders. A formal mathematical model can be reviewed and scrutinized by all stakeholders, thereby ensuring fair representation for all.

How Is the NOAA Chesapeake Bay Office Modeling the Bay’s Ecosystem?

The NOAA Chesapeake Bay Office is using the Ecopath with Ecosim software to develop the Chesapeake Bay Fisheries Ecosystem Model (CBFEM). The effort is guided by the developer of the Ecopath with Ecosim software at the University of British Columbia Fisheries Centre, and by regional scientists and fisheries biologists from research institutions and academic agencies around the Bay.

Why Does the NOAA Chesapeake Bay Office Use Ecopath with Ecosim?

  • Ecopath with Ecosim (EwE) is useful for describing and evaluating ecosystem resources and their interactions:
    • ecosystem effects of fishing, including indirect effects ( e.g., through habitat modifications)
    • effects of environmental change
    • bioaccumulation of persistent pollutants
    • placement of protected marine areas
    • uncertainty in the management process
    • management policy options incorporating economic, social, legal, and ecological considerations
  • EwE is widely and freely distributed, and is used by more than 3,000 users in 125 countries.
  • EwE is being redeveloped and reprogrammed by software architects and programmers (instead of biologists with programming experience). This will facilitate minor modification of EwE to make it more suitable for agencies’ needs. The new version will provide a well-understood baseline and platform for developing a broad array of models that have a unified graphical user interface and output mechanisms. This user interface will have excellent graphics and visualization to facilitate ecosystem learning and understanding by managers and students.

Does the NOAA Chesapeake Bay Office Use Only Ecopath with Ecosim?

  • The NOAA Chesapeake Bay Office supports the development of multiple ecosystem models. Just as the NOAA National Weather Service uses multiple models to predict tomorrow’s weather, an ecosystem is similarly complex and requires multiple models to achieve reliable simulations and projections.
  • The NOAA Chesapeake Bay office provided financial support for the development of the EwE model as well as the Atlantic States Marine Fisheries Commission’s multispecies virtual population analysis (MSVPA) model.
  • To support multiple modeling approaches, the NOAA Chesapeake Bay Office is working with partners from regional offices to support the development of a team of ecosystem modelers around the nation.
  • The NOAA Chesapeake Bay Office developed the Chesapeake Bay Regional Estuarine Ecosystem Model (CBREEM). CBREEM is a simple, linearized, barotropic, two-layer hydrodynamic model; it uses historical climatological, hydrologic, and nutrient-loading data to estimate historical patterns in primary productivity for a regional estuary.
 
Ecosystem modeling helps scientists better understand the Bay.

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