Secondary Production of Infaunal Benthic Communities in Chesapeake Bay in Comparison to Restored Oyster Reefs Amanda Lawless and Dr. Rochelle Seitz Virginia Institute of Marine Science, The College of William & Mary Gloucester Point, VA

Introduction Eastern Oyster, Crassostrea virginica Ecologically and commercially important in Chesapeake Bay Over-harvesting, disease, pollution, and loss of habitat have drastically reduced the population Reef restoration Chesapeake Bay Oyster Harvest (’53-’98)

Chesapeake Bay Lynnhaven Bay

Lynnhaven Bay Characteristics: Shallow Tidal Influence Temperature: 26-32°C Salinity: 19-24 ppt Chesapeake Bay Lynnhaven River Atlantic Ocean Western Branch Eastern Branch Broad Bay Linkhorn Bay

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

Oyster Reefs Oyster Shell Reef Module Reef Rip Rap Reef Reef Ball

Methods Benthic Sampling Bivalves Remaining Infauna Macrofaunal suction (0.11 m2 area to 40 cm depth) Four random samples, prior to reef deployment Bivalves Macoma balthica Tagelus plebeius Remaining Infauna Estimated from previous samples in the Bay (Dauer 2000, 2002 sampling of Elizabeth River)

Calculations - Benthos Total Infaunal Biomass (g AFDW m-2) Bivalves – est. from length/weight regression Remaining Infauna (Dauer 2000, 2002 sampling of Elizabeth River) Multiply by a range of published P:B (Diaz and Schaffner 1990; Baird and Ulanowicz 1989) Production of benthos (g AFDW m-2/yr) Multiply by area of benthos lost per reef type (g AFDW/yr)

Calculations - Oysters Biomass of oysters (g AFDW m-2) Oyster shell – Fishermen’s Island, lower Bay O’Beirn et al. 1999 Modules – Rappahannock River Lipcius and Burke 2006 Rip rap – Lynnhaven system Burke (in progress) Reef balls – 90% module and 10% shell Multiply by a published P:B Dame 1976; Bahr and Lanier 1981 Production of oysters (g AFDW m-2/yr) Multiply by area available for settlement per reef type (g AFDW/yr)

Remaining Infauna Biomass Results - Benthos Site Bivalve Biomass (g AFDW m-2) Remaining Infauna Biomass 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 30.9 – 36.9

Results – Oysters Reef Type Biomass (g AFDW m-2) P:B Production (g AFDW m-2/yr) Area (m2) Total Production (g AFDW/yr) Oyster Shell 600 2.4 1440 0.656 945 * 3 = 2,835 Rip Rap 45.4 109 71.5 * 3 = 214.5 Module 13.7 32.9 4.3 141.5 * 3 = 424.5 Reef Ball 72.3 173.5 416.4 * 3 = 1,249

Benthos vs. Oysters 2,835 63% 55%

Conclusions All reef types compensated for the lost benthic production at the site with lower productivity Oyster shell and reef ball reefs compensated for the lost benthic production at the higher productivity site; however, the rip rap and module reefs may not compensate Revisit the sites in the future Obtain actual oyster production values for the four reef types at each site Revaluate Important to characterize the benthic community prior to reef deployment Determine the best type of reef for a particular area

Acknowledgements Dr. Rochelle Seitz, VIMS Dr. Rom Lipcius, VIMS Community Ecology Group, VIMS Marine Conservation Biology Group, VIMS Chesapeake Bay Foundation US Army Corps of Engineers, Norfolk, VA Office NOAA Chesapeake Bay Office