Ecosystem Modeling and Related Work at the SEFSC

Summarized byJosh Sladek Nowlis

30 August 2007

Multispecies Virtual Population Analysis

• Atlantic States Marine Fisheries Commission-based effort

• Can the recovery of predators (bluefish, striped bass, weakfish) explain menhaden decline?

Nutrients-Phytoplankton-Zooplankton

• Experimental system with rotifers and algae.

• Can set of differential equations explain observed changes in “ecosystem”?

• Despite simplicity and knowledge, difficult to recreate ecosystem dynamics.

Habitat and Stock Assessments

• Stephens and MacCall (2004) technique adopted.

• Uses species assemblages when standardizing fishery-dependent catch rates.

• Assumption is that assemblages indicate the habitat or habitats fished.

Estuarine Habitat

• Productivity of crustaceans (brown shrimp, white shrimp, blue crab) in TX, LA marsh habitat explained and valued by understanding performance related to physical features and habitat quality.

• Pink shrimp in FL Bay…growth and survival as a function of salinity and temperature.

• Similar multispecies effort focused on understanding effects of freshwater flows.

• Significant (p<0.01) effect of inundation and map type

Map typeSolid

Coarse FineOpen

# su

b-ad

ult e

xpor

ts(th

ousa

nds) 300

400500600700800900

InundationLA/LA

LA/TXTX/LA

TX/TX

yz

x

w

Map locationLouisiana Texas

300400500600700800900

x xyy

z

x x

Production and Marsh Habitat

Survival

Growth

Simulated potential harvest

Pink Shrimp Performance

Pelagic and Benthic Habitat

• Oceanographic conditions used to predict abundance and distribution of marine mammals and fish.

• Benthic habitat categories used in Seaflower Biosphere Reserve, Colombia to develop enormous marine protected area network zoned representatively.

The goal is to develop spatially explicit predictionsof animal density and abundance

8 10 12 14 16 18 20 22 24SST

-35

-30

-25

-20

-15

-10

-5

Dep

th

0.0010

0.0020

0.0030 0.0040

0.0050 0.0060

0.00

70

Sightings fromSurveys

Empirical models of the species-environmentrelationship Project these into space

as a density surface

Marine Mammal Habitat Approach

Habitats And Fish• Fish assemblages also corresponded well to a priori

habitat definitions.

-0.5

0.0

0.5

1.0

1.5

2.0

2.5

-0.5 0.0 0.5 1.0 1.5 2.0 2.5 3.0

5GR

Seagrass

4WF

6WF5WF

3WF

1WF2WF

5LG

3WC2WC

1WC

2LP

1LP

6LP

3LP

4LP

3WM

5LP3LS

4LS6LS

5LS 2LS1LS

Mangroves

Forereef

Gorgonian

Crest

Leeward slope

Patch reefs

Ecopath with Ecosim

• Examining effects of apex predator depletion in the Gulf of Mexico.

• Studying potential ecological effects of marine reserve establishment in Puerto Rico.

Complementary Increases

Council EwE Efforts

• Both Gulf of Mexico and South Atlantic Fishery Management Councils are leading EwE efforts.

• In both cases, lead outside scientists check in with Science Center staff on occasion; however, much information conveyed directly to Council staff.

• Potential for problems. Better if the Center would/could take the lead.

Relevant Empirical Data

• Studying snapper-grouper assemblage structure and its spatial distribution in the US South Atlantic.

• Using differential fishing pressure to perform preliminary assessments of large assemblage of Hawaiian shallow water coral reef fishes.

Fishing, Ecology, and Stock Status

Maximum length

Trophic level

Consumption pressure

ln(Stock status) Mobility

Ornamental pressure

-6

-4

-2

0

2

4

6

8

-6 -4 -2 0 2 4 6 8 10

PCA 1

PCA

2

Summary

• Data limitations pose problems, present opportunities.

• Lack of formal Center-wide program is setting up some potential challenges.

• Nonetheless, individual initiative means that the Center does a moderate amount of ecosystem-based work.