NOAA Chesapeake Bay Office Fisheries Ecosystem Modeling Efforts Howard Townsend, Hongguang Ma, and Maddy Sigrist NOAA Chesapeake Bay Office National Ecosystem

NOAA Chesapeake Bay

OfficeFisheries

Ecosystem Modeling Efforts

Howard Townsend, Hongguang Ma, and

Maddy SigristNOAA

Chesapeake Bay Office

National Ecosystem Modeling Workshop

(NEMoW)29-31 August 2007, Southwest Fisheries

Science Center, Santa Cruz Laboratory

Science, Service, & Stewardship

NOAA Chesapeake Bay Office

Ecosystem Modeling: Ecopath with Ecosim (EwE)

Ecopath

Ecosim

Ecospace

Ecotrace



Status of Chesapeake Bay Fisheries Ecosystem: Overview• Ecopath module has been completed.

– 45 trophic groups– 218 diet links– 1950 model gives a snapshot of what the Chesapeake was like 50

yrs ago

• Ecosim module – “Tuned” to some time series data; 60+ data sets and assessments

to replicate the current status and dynamics of the Chesapeake – Simulations can be run to explore policy options (i.e., fisheries

management plans)

• Technical Report (220 pages) is complete and out for review– Data review by Ecosystem Modeling Technical Advisory Panel

(EMTAP)– Dynamics review by another panel? Center for Independent

Experts?



Status of Chesapeake Bay Fisheries Ecosystem: OverviewFocus for the past few years has been on…

1) Data (You can’t have a good model without good data)a) Basic input data for mass balanced snapshot

i. Biomass, Production/Biomass, Consumption/Biomassii. Diet Composition, Catch, and bycatch

b) Time series data for drivers and validation

2) Exploratory simulationsa) Menhaden and Striped Bass interactionb) Blue crab and hypoxia

Drivers• Fishing mortality rates• Fleet effort• Biomass (force) • Time forcing data (e.g.,

prim. prod., SST)

Validation• Biomass (relative, absolute)• Total mortality rates• Catches• Average weights• Diets



Data Pedigree











CBFEM PlansApplications• Support development of ecosystem-based fisheries management

planning process• Tool for exploring ecosystem impacts of fisheries management

decisions in developing EBFM• Provides guidance in identifying research, monitoring and assessment

needs

Development• Review of current model data (basic input, drivers, and validation)

guided by EMTAP under the purview of FSC• Improve data and ensure we have adequately mined data• Link FEM with Water Quality and other physico-chemical models• Explore influence other ecological, climatological, etc. impacts on

the Chesapeake fisheries ecosystem

The ultimate goal is to use CBFEM (and other ecosystem management models) in a process similar to single species stock assessment models. The CBFEM will be developed, reviewed, applied and updated on a regular cycle with oversight from a technical committee.



Need for Technical Review• Currently the model can be used for organizing data and heuristic

exploration of ecosystem/food web interactions. Ultimate plan is for the CBFEM to be used as one of many tools (along with single-species assessments) for ecosystem-based management of fisheries resources

• Heuristic Tool → Management Model– Acceptance by resource managers

» Exposure» Input from Chesapeake research community

– Ensuring best available science is incorporated» Thorough review of data» Thorough review of dynamics

• Under the Information Quality Act (2000), NOAA has to have procedures in place for ensuring and maximizing the “quality, objectivity, utility, and integrity” of information (including statistical information) disseminated by federal agencies. – Necessary for any influential information or information synthesis

product (such as models and fisheries management plans) from NOAA to be publicly disseminated



CBFEM Plans: Research and Management Community Involvement

Management and Application

Research and Academia

FisheriesEcosystem

Model

NOAA-Chesapeake Bay Office&

University of British Columbia

Chesapeake Bay Fisheries Ecosystem Model

Ecosystem Modeling Technical

Advisory Panel

Working with research and academic partners to develop ecosystem tools for resource managers

- Data Compilation & Review- Understanding Ecosystem Dynamics

- Strategic Exploration of Policy Options- Understanding Interconnected Outcomes of

Management Policy

CBP -Scientific and Technical Advisory Panel

Chesapeake Fisheries Steering

Committee

CBP Modeling Subcommittee

(and others)

Developing linkages to Environmental Models

Chesapeake Community Modeling Project

Making connections with multiple managers

Ensuring Scientific Quality

Ensuring Utility to Managers

Chesapeake Research Consortium



Chesapeake Bay Regional Estuarine Ecology 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

• Designed to better encapsulate the Chesapeake Bay’s ecosystem history, and improve the CBFERM’s fit to time series data, a method to capture fluctuations in productivity attributable to primary production was necessary

• Approach developed by Walters et al for Florida Bay



CBREEM – Chlorphyll a index

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

1950 1960 1970 1980 1990 2000

Nut

rient

load

ing

(rela

tive)



Impaired Water

Water Quality Model• Over 90% of the Bay and

its tidal rivers are impaired due to episodic low dissolved oxygen levels and poor water clarity, all related to nutrient and sediment pollution.

• Linking EPA Watershed and Water Quality (Eutrophication) Model to the Fisheries Ecosystem Model to explore how effects of H2O quality on fisheries





Background Info - WQM

Water Quality Model (2002) 13k Cell

• Focus on DO, clarity, and chlorophyll.

• Identified nutrient/sediment allocations which removes water quality impairments.

• Few key living resources (SAV and benthos) included.

• Used to develop the first Chesapeake sediment allocation.



Broad indirect coupling

WQM Output Ecosim forcing function Upper trophic level effects

Monthly average Chlorophyll a from WQM

Striped Bass, Menhaden,

Blue crabs, Oysters



What we are learning from dynamic simulations and linkages to water quality model, in general?• Though the Chesapeake Bay has historically been a well-

studied system, relatively little information on all but a few fisheries species (esp., blue crab, striped bass, oysters)

• Trophic linkages for many important forage species (e.g., Atlantic Menhaden) have not been clearly defined – i.e., we know what eats them, but we do not know what they eat and effects of water quality

• Limited data available for lower trophic levels and species/groups that are not targeted for harvest

• Historical catch data (and biomass data) for some species is not available or of limited value, so diamond mining of data is necessary

• Connections between habitat, water quality, and fisheries have not been thoroughly tested, but lots of just-so stories circulating

• Integrated fish surveys and water quality monitoring would be valuable

Documents

NOAA Chesapeake Bay Office Fisheries Ecosystem Modeling Efforts Howard Townsend, Hongguang Ma, and Maddy Sigrist NOAA Chesapeake Bay Office National Ecosystem