Habitat Workshop - March 1 & 2, 2012

1

Ecosystem Modeling Framework For Quantitative Seascape

Ecology Supporting Ecosystem Assessment and Management

Howard TownsendNOAA/NMFS/OHC/Chesapeake Bay

Robert GambleNOAA/NMFS/NEFSC/ EcoAP

How and When to Use Models: Adaptive Management

1. Identify the problem (a management question or an ecological hypothesis)

2. Use existing data to develop a first cut model of the system

3. Collect relevant data4. Refine models with data5. Apply model to the problem6. Assess utility of model to solve problem, and refine (the

problem, the data, and/or the model)7. Repeat steps 3-6 until the problem is sufficiently resolved

Example: How and When to Use Models

1. Chesapeake Blue Catfish

2. NE US Atlantis example

Chesapeake Bay – Blue Catfish• Applied fisheries ecosystem models (using EwE) to generate

quantitative estimates of the impacts of BCF on other species. This is first attempt to assimilate our knowledge on BCFs in the ecosystem (step 2).

• Ran management scenarios to understand how fisheries and water quality management can be used to regulate BCF (steps 5-6).

• Used ecosystem model to guide research and monitoring directions (steps 3-4).

Identify a problem and model

• Baseline Scenario– Hypothetically maintain

status quo in current fishing regulations and effort

– 20-yr projection of changes in Biomass of key species

• Baseline Major Impacts– White Perch– Alosines– Blue Crabs– Striped Bass– Croaker

% Biomass Change, SQ: Status Quo

Striped Bass

White PerchAlosines

Menhaden

Blue Crab Blue Catfish

Apply Model and Assess Utility

• Increasing exploitation rates had little affect on blue catfish populations.• An overwhelming control of the system through different levels of nutrient inputs.• Perhaps habitat has more of an influence than fishing?

Refine Model – Include habitat and seascape/water quality

Longer Term…Finer spatial scale evaluation of BCF in the Chesapeake Bay system. Model would be completed using the Ecospace option within EwE.

Ecospace model could provide…-Spatially specific predator and prey interactions.-Better understanding impacts of BCF impacts on anadromous species. -Opportunity to include current research for more precise parameterization of the CBFEM.-Recommendations on where tributary specific removal campaigns may be effectively applied.

ATLANTIS NEUS – Model Structure

0

50

120+

300+

Sediment

Epibenthic

Pelagic

Northeast United States – (22, 8)

ATLANTIS NEUS – Model Structure

45 Functional Groups

18 Fishing fleets(based on gear and target species)

ATLANTIS NEUS – Habitat Parameters

Benthic• Depth (determines number of layers)• Bottom type (scallop, other bivalves, reef, flat, soft, canyon)• Patchiness of bottom type• How resistant to damage from fishing the bottom is

Oceanographic• Temperature (time series, or modeled)• Salinity (time series, or modeled)• Current flows (average flows per unit time across box edges)

Biological• Nutrients (locations of high concentration, changes over time)

ATLANTIS NEUS – Habitat Usage In the Model

Habitat types:• Fisheries can be flagged to avoid any of the habitat types• Functional groups prefer specific habitat types (juveniles or adults)• Effects of degradation can be simulated• Effects of closures for habitat types can be simulated

Nutrients:• Location and magnitude affects primary productivity and food web effects in the model• Effects of lower or higher nutrient levels can be simulated

Temperature and Salinity:• Climate change effects can be simulated, with regards to distribution and abundance of functional groups

ATLANTIS NEUS – Habitat Time & Spatial Scales

Temporal Scales: • Any time step permitted, but generally done at half day to daily scales

Spatial Scales: • Generally 10’s – 1000’s km2 dependent on scale important to the functional groups and fisheries

ATLANTIS NEUS – Example

Effects of closing eastern portion of Georges Bank

-10%

-5%

0%

5%

10%

15%

20%

25%

30%

35% Mackerel

Herring

White Hake

Bluefish

Other demersal flatfish

Large pelagics

Migratory mesopelagics

Other pelagics

Goosefish

Anadromous small pelagics

Cod

Silver Hake

Other demersals

Haddock

YT

-10%

-5%

0%

5%

10%

15%

20%

25%

30%

35%

40%

Squid

Scallops

Other benthic filter feeders

Benthic herbivorous grazers

Lobster

Shallow macrozoobenthos

Prawns

42The answer is… *

What was the question?

* D. Thought, personal communicatiom

Useful Ecosystem Modeling Frameworks

• Existing software (code base) packages– Ecopath with Ecosim– Atlantis

• Made from scratch– BSIERP– Others