Secondary Production of Secondary Production of Infaunal Benthic Communities in Infaunal Benthic Communities in Chesapeake Bay in Comparison Chesapeake Bay in Comparison

to Restored Oyster Reefsto Restored Oyster Reefs

Amanda Lawless and Dr. Rochelle SeitzAmanda Lawless and Dr. Rochelle Seitz

Virginia Institute of Marine Science, Virginia Institute of Marine Science, The College of William & MaryThe College of William & Mary

Gloucester Point, VAGloucester Point, VA

IntroductionIntroduction

Eastern Oyster, Eastern Oyster, Crassostrea virginicaCrassostrea virginica Ecologically and commercially important Ecologically and commercially important

in Chesapeake Bayin Chesapeake Bay

Over-harvesting, disease, Over-harvesting, disease, pollution, and loss of pollution, and loss of habitat have drastically habitat have drastically reduced the populationreduced the population

Reef restorationReef restoration

Chesapeake Bay Oyster Harvest (’53-’98)

Chesapeake BayChesapeake Bay

Lynnhaven Bay

Lynnhaven BayLynnhaven BayChesapeake Bay

Atla

ntic

Oce

an

Western Branch Eastern BranchLynnhaven River

Broad Bay

Linkhorn Bay

Characteristics:

Shallow

Tidal Influence

Temperature: 26-32°C

Salinity: 19-24 ppt

ObjectiveObjective

To compare the productivity of a lost To compare the productivity of a lost benthic community to the productivity of benthic community to the productivity of oysters on four types of oyster reefsoysters on four types of oyster reefs

Oyster ReefsOyster Reefs

Oyster Shell Reef

Module Reef

Rip Rap Reef

Reef Ball

MethodsMethods Benthic SamplingBenthic Sampling

Macrofaunal suction (0.11 mMacrofaunal suction (0.11 m22 area to 40 cm depth)area to 40 cm depth)

Four random samples, prior to reef Four random samples, prior to reef deploymentdeployment

BivalvesBivalves Macoma balthicaMacoma balthica Tagelus plebeiusTagelus plebeius

Remaining InfaunaRemaining Infauna Estimated from previous samples Estimated from previous samples

in the Bay in the Bay • (Dauer 2000, 2002 sampling of Elizabeth River)(Dauer 2000, 2002 sampling of Elizabeth River)

Calculations - BenthosCalculations - Benthos Total Infaunal Biomass (g AFDW mTotal Infaunal Biomass (g AFDW m-2-2))

Bivalves – est. from length/weight regressionBivalves – est. from length/weight regression Remaining Infauna Remaining Infauna

• (Dauer 2000, 2002 sampling of Elizabeth River)(Dauer 2000, 2002 sampling of Elizabeth River)

Multiply by a range of published P:BMultiply by a range of published P:B• (Diaz and Schaffner 1990; Baird and Ulanowicz 1989)(Diaz and Schaffner 1990; Baird and Ulanowicz 1989)

Production of benthos (g AFDW mProduction of benthos (g AFDW m-2-2/yr)/yr)

Multiply by area of benthos lost per reef Multiply by area of benthos lost per reef type (g AFDW/yr)type (g AFDW/yr)

Calculations - OystersCalculations - Oysters Biomass of oysters (g AFDW mBiomass of oysters (g AFDW m-2-2))

Oyster shell – Fishermen’s Island, lower BayOyster shell – Fishermen’s Island, lower Bay• O’Beirn et al. 1999O’Beirn et al. 1999

Modules – Rappahannock RiverModules – Rappahannock River• Lipcius and Burke 2006Lipcius and Burke 2006

Rip rap – Lynnhaven systemRip rap – Lynnhaven system• Burke (in progress)Burke (in progress)

Reef balls – 90% module and 10% shellReef balls – 90% module and 10% shell

Multiply by a published P:BMultiply by a published P:B• Dame 1976; Bahr and Lanier 1981Dame 1976; Bahr and Lanier 1981

Production of oysters (g AFDW mProduction of oysters (g AFDW m-2-2/yr)/yr)

Multiply by area available for settlement per reef Multiply by area available for settlement per reef type (g AFDW/yr)type (g AFDW/yr)

Results - BenthosResults - BenthosSite Bivalve Biomass

(g AFDW m-2)Remaining Infauna

Biomass(g AFDW m-2)

P:B Production (g AFDW m-2/yr)

Eastern Branch

19.66 0.931 2.9 - 7.7

59.7 – 158.6

Linkhorn 9.73 0.931 2.9 - 7.7

30.9 – 36.9

Eastern Branch Linkhorn

Production (g AFDW m

-2/yr)

0

50

100

150

200

250

LowHigh

Results – OystersResults – OystersReefType

Biomass(g AFDW m-2)

P:B Production (g AFDW m-2/yr)

Area(m2)

Total Production(g AFDW/yr)

OysterShell

600 2.4 1440 0.656 945 * 3 = 2,835

Rip Rap 45.4 2.4 109 0.656 71.5 * 3 = 214.5

Module 13.7 2.4 32.9 4.3 141.5 * 3 = 424.5

Reef Ball 72.3 2.4 173.5 2.4 416.4 * 3 = 1,249

Shell Rip Rap Module Reef Ball

Production (g AFDW m

-2/yr)

0

100

200

300

1200

1300

1400

1500

Benthos vs. OystersBenthos vs. Oysters

Shell Rip Rap Module Reef Ball

Production (g AFDW/yr)0

100

200

300

400

1100

1200

1300

1400

1500Eastern Branch Linkhorn Oyster Production

2,835

55%

63%

ConclusionsConclusions All reef types compensated for the lost benthic production at the site All reef types compensated for the lost benthic production at the site

with lower productivitywith lower productivity

Oyster shell and reef ball reefs compensated for the lost benthic Oyster shell and reef ball reefs compensated for the lost benthic production at the higher productivity site; however, the rip rap and production at the higher productivity site; however, the rip rap and module reefs may not compensate module reefs may not compensate

Revisit the sites in the futureRevisit the sites in the future Obtain actual oyster production values for the four reef types at each site Obtain actual oyster production values for the four reef types at each site RevaluateRevaluate

Important to characterize the benthic community prior to reef Important to characterize the benthic community prior to reef deployment deployment

Determine the best type of reef for a particular areaDetermine the best type of reef for a particular area

AcknowledgementsAcknowledgements

Dr. Rochelle Seitz, VIMSDr. Rochelle Seitz, VIMS Dr. Rom Lipcius, VIMSDr. Rom Lipcius, VIMS Community Ecology Group, VIMSCommunity Ecology Group, VIMS Marine Conservation Biology Group, VIMSMarine Conservation Biology Group, VIMS Chesapeake Bay FoundationChesapeake Bay Foundation US Army Corps of Engineers, Norfolk, VA OfficeUS Army Corps of Engineers, Norfolk, VA Office NOAA Chesapeake Bay OfficeNOAA Chesapeake Bay Office