Kingsley-Smith, P. R.,

Inter-site and inter-specific differences in rates of survival and growth of C. ariakensis and C. virginica:

A collaborative on-bottom study in Virginia and Maryland

Kingsley-Smith, P. R., Harwell, H. D, Kellogg, M. L., Allen, S. K. Jr., Meritt, D. W.,

Paynter, K. T. Jr. & Luckenbach, M. W.

9th International Conference on Shellfish Restoration Charleston, South Carolina, USA

November 15th-19th 2006

FUNDING SOURCES

COLLABORATORS

University of Maryland Center for Environmental Science (UMCES)

Horn Point Laboratory

• Current knowledge of C. ariakensis survival and growth rates is based upon 1) field trials using triploids in off-bottom, caged aquaculture, and 2) quarantined studies using diploids.

• Predicting rates of survival and growth of C. ariakensis in natural bottom habitats is critical to a pending decision on an intentional introduction.

• Accurate determination of these rates will improve parameterization of a developing demographic model.

• This study is the first to grow C. virginica and C. ariakensis (in VA and MD) side-by-side on the bottom in an effort to gather survival and growth data in a more naturalistic setting.

I. INTRODUCTION

Triploid Triploid C. ariakensisC. ariakensis and and C. virginica C. virginica werewere set on shell in May 2005 andset on shell in May 2005 and planted at ~400 oysters mplanted at ~400 oysters m-2-2 in late Oct–Nov 2005 at 4 sites in VA and MD. in late Oct–Nov 2005 at 4 sites in VA and MD.

II. METHODS

Oysters were planted in 2’ x 2’ bread trays in 5 x 5 arrays in late Oct-Nov 2005.

II. METHODS

Cages were placed around the trays to prevent disturbances by large epibenthic predators (e.g., cownose rays) and humans, while allowing access

to small predators (e.g., xanthid crabs).

II. METHODS Machipongo River Virginia

Treatments (single treatment per cage):Treatments (single treatment per cage):

• C. virginicaC. virginica only only

• C. ariakensisC. ariakensis only only

• C. virginicaC. virginica and and C. ariakensis C. ariakensis in a 50 : 50 mixin a 50 : 50 mix

• Shell only (no live oysters)Shell only (no live oysters)

Experimental design:Experimental design:

• 2 replicate cages (blocks 1 and 2) per treatment (4) at each field site.

• 4 sites (2 sites in Virginia; 2 sites in Maryland).

• Sites were chosen to cover a range of salinities, water depths, disease pressures and relative predator abundances.

II. METHODS

Atlantic Ocean

Delaware

Bay

Chesapeake

Bay

25 km

Patuxent River

York River

Severn River

Machipongo River

II. METHODS

MACHIPONGO RIVER, VAMACHIPONGO RIVER, VA

Intertidal Intertidal Salinity: ~30 psuSalinity: ~30 psuPredation pressure: HighPredation pressure: HighHigh Dermo & High MSXHigh Dermo & High MSX

II. METHODS

YORK RIVER, VAYORK RIVER, VA Subtidal (1-2m)Subtidal (1-2m)Salinity: 20-25 psuSalinity: 20-25 psuPredation pressure: HighPredation pressure: HighHigh Dermo & High MSXHigh Dermo & High MSX

II. METHODS

PATUXENT RIVER, MDPATUXENT RIVER, MD

Subtidal (3-4m) Subtidal (3-4m) Salinity: 8-10 psuSalinity: 8-10 psuPredation pressure: ModeratePredation pressure: ModerateLow Dermo & No MSXLow Dermo & No MSX

SEVERN RIVER, MDSEVERN RIVER, MD

Subtidal (3-4m)Subtidal (3-4m)Salinity: 5-8 psuSalinity: 5-8 psuPredation pressure: LowPredation pressure: LowNo Dermo & No MSXNo Dermo & No MSX

II. METHODS

Courtesy of Paynter Lab

Courtesy of Paynter Lab

• Sampling = removal of 3 trays from each cage and replacement of sampled trays with those containing only clean shell.

• Cages were sampled one month after deployment (i.e., Nov-Dec 2005) to assess handling and early post-deployment mortality.

• Quarterly sampling thereafter:

Apr 2006, July 2006 and Oct 2006.

• Future sampling: Apr 2007, July 2007 and Oct 2007.

II. METHODS

This study will provide data on the following parameters:

oyster survival (# live oysters)oyster growth (shell height mm)oyster biomass (ash-free dry weight)ploidy/reversion (biosecurity)disease (RFTM & histology)gametogenesis (histology)

comparisons of habitat complexity between treatments (spp.) and its relationship to associated free-living and attached faunal assemblages.

(Poster by Heather Harwell et al.).

II. METHODS

This study will provide data on the following parameters:

oyster survival (# live oysters)oyster growth (shell height mm)oyster biomass (ash-free dry weight)ploidy/reversion (biosecurity)disease (RFTM & histology)gametogenesis (histology)

comparisons of habitat complexity between treatments (spp.) and its relationship to associated free-living and attached faunal assemblages.

(Poster by Heather Harwell et al.).

II. METHODS

July 2006

III. RESULTS – SURVIVALSURVIVAL

MACHIPONGO RIVER YORK RIVER

PATUXENT RIVER SEVERN RIVER

140

120

100

80

60

40

20

0

140

120

100

80

60

40

20

0

140

120

100

80

60

40

20

0

140

120

100

80

60

40

20

0

Oct Nov Dec Jan Feb Mar Apr May Jun Jul Oct Nov Dec Jan Feb Mar Apr May Jun Jul

Oct Nov Dec Jan Feb Mar Apr May Jun Jul Oct Nov Dec Jan Feb Mar Apr May Jun Jul

20062005 20062005

2006200520062005

Mea

n no

. oy

ster

tra

y -1

C. virginicaC. ariakensis

Single spp. cages onlySingle spp. cages onlyError bars are S.D.sError bars are S.D.s

(n = 6)(n = 6)

Error bars are S.E.sIII. RESULTS – SURVIVAL - Within site comparisons

100

80

60

40

20

0

Mea

n #

live

oyst

ers

per

tray

1 2 1 2 1 2 1 2

Machipongo York Patuxent Severn


100

80

60

40

20

0

Mea

n #

live

oyst

ers

per

tray

1 2 1 2 1 2 1 2



BLOCKS & SPP. NOT SIGNIFICANTLY

DIFFERENT

SIGNIFICANT BLOCK & SPP.

EFFECTS

III. RESULTS – SURVIVAL - Within site comparisons

100

80

60

40

20

0

Mea

n #

live

oyst

ers

per

tray

1 2




combined combined combined

Error bars are S.E.s

100

80

60

40

20

0

Mea

n #

live

oyst

ers

per

tray

1 2





ns


100

80

60

40

20

0

Mea

n #

live

oyst

ers

per

tray

1 2



Intertidal

Subtidal

ns




100

80

60

40

20

0

Mea

n #

live

oyst

ers

per

tray

1 2



MLW

MLW + 1ft

Intertidal

Subtidal

ns




Machipongo River Virginia


BLOCK 1

BLOCK 2


100

80

60

40

20

0

Mea

n #

live

oyst

ers

per

tray

1 2



MLW

MLW + 1ft

Intertidal

Subtidal

(p = 0.06)

ns



MSX?predation?


100

80

60

40

20

0

Mea

n #

live

oyst

ers

per

tray



III. RESULTS – SURVIVAL – Across site comparisons

combined combined combined combined



100

80

60

40

20

0

Mea

n #

live

oyst

ers

per

tray


A AB BC C

C. virginica across site comparisons




100

80

60

40

20

0

Mea

n #

live

oyst

ers

per

tray


A AB BC C





100

80

60

40

20

0

Mea

n #

live

oyst

ers

per

tray


A AB BC C





100

80

60

40

20

0

Mea

n #

live

oyst

ers

per

tray


A AB BC C



increasing survival

decreasing salinity



100

80

60

40

20

0

Mea

n #

live

oyst

ers

per

tray




Machipongo represents suitable

habitat for C. virginica (survival comparable with York River)….

A AB BC C


100

80

60

40

20

0

Mea

n #

live

oyst

ers

per

tray


a

b

C. ariakensis across site comparisons

bb



…but less suitable habitat for C. ariakensis


MACHIPONGO RIVER, VA JULY 5MACHIPONGO RIVER, VA JULY 5THTH 2006 2006 YORK RIVER, VA JULY 24YORK RIVER, VA JULY 24THTH 2006 2006

PATUXENT RIVER, MD JULY 10PATUXENT RIVER, MD JULY 10THTH 2006 2006 SEVERN RIVER, MD JULY 17SEVERN RIVER, MD JULY 17THTH 2006 2006

Shell height (mm)Shell height (mm)

# # oy

ster

soy

ster

s


0

25

50

75

0- 10- 20- 30- 40- 50- 60- 70- 80- 90- 100- 110-0

25

50

75

0- 10- 20- 30- 40- 50- 60- 70- 80- 90- 100- 110-

0

25

50

75

0- 10- 20- 30- 40- 50- 60- 70- 80- 90- 100- 110-

0

25

50

75

0- 10- 20- 30- 40- 50- 60- 70- 80- 90- 100- 110-

III. RESULTS – GROWTHGROWTH

(Data include oysters from both single and mixed spp. cages.)

• Survival and growth data are now available for triploid C. ariakensis and C. virginica from several bottom habitats ranging in salinity, depth, disease pressure and relative predator abundance.

• Significant interactions were observed between sites and species for both survival and growth.

• Lowest survival of both species was observed at the intertidal Machipongo River site, with C. ariakensis survival especially low.

• Highest growth rates of C. ariakensis were observed at the York River (site characteristics: subtidal & high salinity).

• Both species (particularly C. virginica) show a trend of increased survival with decreasing salinity across sites.

• Growth rates of C. virginica and C. ariakensis were most similar at the low salinity Severn River site.

IV. CONCLUSIONS

Eastern Shore Lab

Reade Bonniwell

PG Ross

Sean Fate

Alan Birch

Edward Smith

Jamie Wheatley

Al Curry

Stephanie Bonniwell

Rochelle Brown

University of Maryland (sampling help)

Jake Goodwin

Mark Sherman

Steve Allen

Marcy Chen

Nancy Ward

VIMS ABC

Shane Bonnot

Ryan Gill

Karen Hudson

ESL Summer aides

Raija Bushnell

Sarah Mallette

Matt Foley

Andrew Wilson

Andrew Matkin

VIMS Shellfish Pathology Lab

Ryan Carnegie

Rita Crockett

Susan Denny

V. ACKNOWLEDGEMENTS

2

4

6

8

10

% f

requ

ency

shell height (mm)

5 10 15 20 25 30 35 40

Pre-deployment shell height distributions

C. ariakensis (mean SH = 13.85mm, n = 1272)C. virginica (mean SH = 12.80mm, n = 1362)

Documents

Kingsley-Smith, P. R.,