Karen Kesler, Vincent Politano, Kennedy Paynter

Differentiating the impact of the physical and biotic components of the eastern oyster,

Crassostea virginica, on the benthic reef community

The physical and biotic contributions of Crassostrea virginica

• Physical Structure:• Hard surface for settlement

• Complex arrangement of oyster shells (Luckenbach et al. 2005)

• Complexity correlated with higher biomass, abundance, and species richness (Cranfield et al 2004, Coen et al. 2007)

• Reduces turbidity (Meyer and Townsend 2000)

•Biotic Input:• Benthic-pelagic couplers

• Biodeposit production

Past Research

• Tolley and Volety 2005: C. virginica

• No overall difference between live and shell treatments

• Some species level differences

• Silver Botts et al. 1996: Dreissena spp

• no differences in amphipods, turbellarians, and hydrozoans abundances

• Chironomid abundance higher on live mussels

• Stewart et al. 1998: Dreissena spp

• macroinvertebrate biomass higher on live mussels

Question and Hypotheses

• Is the Crassostrea virginica reef community predominantly responding to the presence of the oyster structure or is there an additional response to the biotic component of a live oyster?

• Ho: The two treatments will have equal abundance and biomass.

• May indicate structure as the dominating influence

• HA: The live oyster treatment will have higher abundance and/or biomass.

• May indicate an additional benefit of live oyster

Methods

• In July 2009, eighty C. virginica clumps were collected from the Chester River, MD

• Clumps were cleaned of all epibiotics

• Half of the clumps were shucked and glued shut to reassemble the structure of a live oyster

• 4 clumps were zip tied to a 57.8 cm2 tray

• 10 trays of live oysters and 10 trays of oyster shell of equal complexity were deployed into the Patuxent River, MD

• Trays were placed 3 m apart in a 12 m by 15 m grid

Methods

• In October 2009 three trays of each treatment were removed for a mid-experiment evaluation

• Oysters and epifauna were preserved in ethanol

• Epifauna were cleaned from the oysters, identified, enumerated, and biomassed

• ANOVA with an adjusted alpha was performed

Results: Least Abundant Taxa

0100200300400500600700800900

1000LiveOyster Shell

Taxa

Ab

un

dan

ce p

er t

ray

Results: Most Abundant Taxa

polychaeta amphipoda platyhelminthes copepoda0

5000

10000

15000

20000

25000

30000LiveOyster Shell

Taxa

Ab

un

dan

ce p

er t

ray

Results: Taxa with Lowest Biomass

cirrip

edia

biva

lvia

poly

chae

ta

amph

ipod

a

actin

iaria

platy

helm

in...

misc

.

gastr

opod

a

cope

poda

xant

hoid

ea

isopo

da

shrim

p0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8Live

Oyster Shell

Taxa

Dry

bio

mas

s p

er t

ray

(g)

Results: Taxa with Highest Biomass

teleostei tunicata0

1

2

3

4

5

6Live

Oyster Shell

Taxa

Dry

bio

mas

s p

er t

ray

(g)

Discussion

• No difference in reef community biomass or abundance

• Structure may have been a stronger influence on community development than the biotic component

• Tidal movement and wave action may have influenced results

What’s Next ?

• Remaining 14 trays moved to deeper water in November 2009

• Reduced influence of tidal and wave action

• Removed in July 2010

• Currently processing trays

• New data will present a more refined data set

Acknowledgements

• Paynter Lab staff and students

• Kyle Rambo: Naval Air Station, Patuxent River

• Oyster Recovery Partnership (ORP)

• National Oceanic and Atmospheric Administration – Chesapeake Bay Office (NCBO)

• Army Corps of Engineers, Baltimore District

References

• Coen, LD, RD Brumbaugh, D Bushek, R Grizzel, MW Luckenbach, MH Posey, SP Powers, and SG Tolley. 2007. Ecosystem services related to oyster restoration. Marine Ecology Progress Series 341: 303-307.

• Cranfield, HJ, AA Rowden, DJ Smith, DP Gordon, and KP Michael. 2004. Macrofaunal assemblages of benthic habitat of different complexity and the proposition of a model of biogenic reef habitat regeneration in Foveaux Strait, New Zealand. Journal of Sea Research 52: 109- 125.

• Luckenbach, MW, LD Coen, PG Ross, Jr. and JA Stephen. 2005. Oyster reef habitat restoration: relationships between oyster abundance and community development based on two studies in Virginia and South Carolina. Journal of Coastal Research 40: 64-78.

• Meyer, DL, and EC Townsend. 2000. Faunal utilization of created intertidal eastern oyster (Crassostrea virginica) reefs in the southeastern United States. Estuaries 23(1): 34-45.

• Silver Botts,P, BA Patterson and DW Schloesser. 1996. Zebra mussel effects on benthic invertebrates: physical or biotic? Journal of the North American Benthological Society 15(2): 179-184.

• Stewart, TW, JG Miner, and RL Lowe. 1998. Quantifying mechanisms for zebra mussel effects on benthic macroinvertebrates: organic matter production and shell-generated habitat. Journal of the North American Benthological Society 17(1): 81-94.

• Tolley, SG and AK Volety. 2005. The role of oysters in habitat use of oyster reefs by resident fishes and decapod crustaceans.  Journal of Shellfish Research 24(4):  1007-1012.

Questions?