Oyster Castles: A New Tool for Site Evaluation and Intertidal Oyster

Oyster Castles: A New Tool for Site Evaluation and Intertidal

Oyster Reef Habitat Restoration and Enhancement in Multiple U.S. East Coast States

Benjamin W. Stone 1

Peter Kingsley-Smith 1, Bowdoin Lusk 2, Barry Truitt 2, Joy Brown 3, Mark Faherty 4 & Gus Lorber 5

1 South Carolina Department of Natural Resources’ Marine Resources Research Institute

2 The Nature Conservancy Virginia Coast Reserve3 The Nature Conservancy South Carolina Chapter

4 Massachusetts Audubon / Wellfleet Bay Wildlife Sanctuary

5 Allied Concrete Co.

Background• Increasing pressure on coastal habitats• Multiple drivers of oyster reef habitat loss• Importance of ecological services• Decreasing availability and high price of

oyster shell• Use of novel materials as substrate• Suitability and potential success of reef

restoration and enhancement sites• Application of site evaluation approaches

Origin of the Oyster Castle

Virginia

South Carolina

Massachusetts

Massachusetts Audubon and Wellfleet Bay Wildlife Sanctuary

• Deployed June 2009• ~500 blocks divided

among 9 replicate castle arrays

• Density: Oysters m-2

• Size: Mean shell height (mm)

• Winter oyster mortality• Sites are open to

harvesting

Virginia Coastal Reserve• 3 sites established in June-July 2008

(~500 blocks) – November 2008 shown top right; October 2010 shown bottom right

• 2 additional sites established in June 2009 (~500 blocks)

• 1 site established in March-April 2010 on a larger scale (bottom left) and castles added to 2 existing sites (~1488 blocks)

South Carolina Oyster Castles• Deployed at 3 sites on Jeremy

Island in July 2009 using volunteers

• Eight arrays of 13 oyster castles

• Monitored quarterly from Dec 2009 until Nov 2010

• Castles constructed in Winyah Bay

Sampling Method

Bottom

Middle

Top Nor

th

Sout

h East

West

Photographed region

Elevationand

Orientation

Photographic analysis

AnalysisData from SC sites sampled in December 2009Oyster size data: oyster shell height (mm)Oyster density data: number of oysters m-2

Count no. of live oysters in each photograph (sample area)Determine sample area (m2) to calculate oysters m-2

Data tested for normality - assumptions of ANOVA modelsInvestigated main effects of site, elevation and orientation

and their interactionsNon-significant terms removed and reduced models re-runSplit analysis into the three sites-Casino, ICW, Skrine

Effect of elevation on oyster survival

•One-way ANOVA

• Significant at ICW & Skrine sites; not significant at Casino

• Tukey’s 95% C.I. post-hoc analysis

•ICW: Top > Bottom = Middle

•Skrine: Top = Middle > Bottom

Bottom Middle Top0

200400600800

100012001400

Skrine

Elevation

Oys

ters

m-2

Bottom Middle Top0

500

1000

1500

2000

2500

ICW

Elevation

Oys

ters

m-2

One-way ANOVASkrine only:

significantTukey’s 95% C.I.South = West > EastNorth not

significantly different from other orientations

Effect of orientation on oyster survival

North South East West0

200400600800

100012001400

Skrine

OrientationO

yste

rs m

-2

Oyster size analysesSignificance effects of:

SiteReplicate (castle)ElevationOrientationElevation*Orientation

Analysis ongoing

605040302010

9

8

7

6

5

4

3

2

1

0

shell height (mm)

% Fr

eque

ncy

CasinoMean=35.9 mm

605040302010

10

8

6

4

2

0

shell height (mm)

% Fr

eque

ncy

SkrineMean=25.47

mm

6050403020100

10

8

6

4

2

0

shell height (mm)

% Fr

eque

ncy

ICWMean=25.7 mm

ConclusionsCastles have utility as small-scale evaluation

tools and larger scale restoration substrate.Elevation significantly affects early post-

settlement oyster survival.Higher predation rates on lower elevations?Orientation affected survival only at one site

and patterns were not intuitive.Small-scale differences in oyster growth

rates.Success of restoration sites can be highly site

specific.

Acknowledgements Amanda Fornal 1

Ryan Joyce 2

Kristin Schulte 1

Eric Krueger 3

Kristine Hartvigsen 3

Mary Conley 3

Melissa Spotts 3 Neil Jordan 3

Pam Marfizo 3 Robert Newton 3 Ryan Olson 3 Sarah Hartman 3

Shari Wibert 3

Jim Yergin John Kooper Carl Kooper

Alec Adams Ashley Ammons David Mikell Jeanna Crockett Vicki Bullock Andrew Kazilieras Caroline Hetchell Kelly Courtney

South Carolina Department of Natural Resources 1

College of Charleston 2

The Nature Conservancy 3

Thank you for your attention.

Benjamin W. StoneWildlife BiologistShellfish Research SectionMarine Resources Research InstituteSouth Carolina Department of Natural Resourcesstoneb@dnr.sc.gov