Download Interspecific interactions in oyster reef communities: the effect of

Ecological considerations for oyster
restoration: interactions between oyster
larvae and reef-associated fauna
Brian B. Barnes*, Mark W. Luckenbach,
Peter R. Kingsley-Smith
Plight of oysters in Chesapeake Bay
Commercial oyster landings
(millions of pounds)
120
Current Crassostrea virginica population
levels in Chesapeake Bay are < 1%
biomass of those at the start of the
last century (Newell, 1988)
90
60
Virginia landings
Maryland landings
30
1880
1900
1920
1940
1960
2000
1980
chesapeakebay.noaa.gov
Supplementing shell substrate

Shells are limiting to
epibenthic fauna
AND restoration
managers

Substrate additions are
often done without
regard for how
substrate colonization
affects oysters

Shell planting on Rappahannock River
Epifaunal interactions research is often conducted
using artificial substrates
Research Objectives

Investigate the effects of single-species
epifaunal populations on the recruitment
of oyster larvae using natural substrates

Effect of water soluble cues

Effect of clamworms (Neanthes succinea)
Collection sites
a
b
Pungoteague Creek site
Rappahannock River site
a
VIMS ESL
b
Images from maps.google.com
Experimental treatments
No fouling
Membranipora tenuis
Cliona sp.
Balanus
improvisus
Barnacle Mould
Dead Barnacle
Microcosm design – Effect of epifauna
~ 75 larvae
50 ml adult oyster
bathwater
.
.
.
.
. . . .. . . ..... .
. . ..
Test shell
(~3 cm x ~3 cm)
Combusted very fine
sand (63 – 125 μm)
4.3 cm
5.7 cm
Overall layout
.
. .. .. .. .. . .. . .
. .. ..
.
.
=
x 16
Results – Effect of epifauna on oysters:
Settlement rate, Experiment 1 (C. a.)
Larval Settlement (% )
0.6
*
0.5
0.4
0.3
0.2
0.1
0
Pos Control
Low Barnacle Med Barnacle High Barnacle
Treatment
Bryozoan
Cliona
Results – Effect of epifauna on oysters:
Settlement Rate
Experiment
Species
C. virginica
1
C. ariakensis
2
C. virginica
3
C. ariakensis
4
C. virginica
5
C. virginica
6
C. ariakensis
7
C. virginica
Low
Barnacles
Medium
Barnacles
High
Barnacles
+
p = 0.0254
+
+
+
+
+
p = 0.0184
+
p = 0.0093
+
+
+
Bryozoans
+
p = 0.0001
+
+
p < 0.0001
+
-
+
+
p = 0.0147
+
p = 0.0001
+
p = 0.0034
+
Dead
Barnacles
Barnacle
Moulds
-
-
Cliona
p = 0.0282
p = 0.0003
+
p = 0.0412
Results – Effect of epifauna on oysters:
Mortality
Experiment
Species
C. virginica
Low
Barnacles
+
1
C. ariakensis
2
C. virginica
3
C. ariakensis
4
C. virginica
5
C. virginica
6
C. ariakensis
7
C. virginica
Medium
Barnacles
High
Barnacles
Bryozoans
Cliona
+
+
+
p = 0.0066
+
-
+
+
+
Dead
Barnacles
Barnacle
Moulds
+
p = 0.0195
+
p = 0.0012
+
p = 0.0001
+
+
+
+
+
+
+
+
-
-
+
+
+
+
+
+
p = 0.0047
+
p < 0.0001
+
p < 0.0001
+
+
Microcosm design – Effect of bathwaters
.
. ..
.
.
.. . ... . .
.
. . .. ..
.
5.7 cm
~ 75 larvae
50 ml adult
bathwater
4.3 cm
Results – Bathwater experiments
Larval Settlement (%)
*
0.2
*
*
0.15
0.1
0.05
Larval Settlement (%)
0.14
0.25
0.12
0.1
0.08
0.06
0.04
0.02
0
0
Control
Oyster
Barnacle
Control
Oyster + Barnacle
0.7
0.6
0.5
*
0.4
Clamworm
0.6
*
0.3
0.2
0.1
Larval Mortality (%)
Larval Mortality (%)
*
0.8
Barnacle
Bathwater Treatment
Bathwater Treatment
0.9
Oyster
*
0.5
0.4
0.3
*
0.2
*
0.1
0
0
Control
Oyster
Barnacle
Bathwater Treatment
Oyster + Barnacle
Control
Oyster
Barnacle
Bathwater Treatment
Clamworm
Conclusions


No clear differences between C. virginica and
C. ariakensis larvae
Balanus improvisus presence likely affects settling oyster
larvae




Increased structure likely not important
Water soluble cue causes mortality, increased settlement
Membranipora tenuis largely inert to mortality and
settlement rate of oyster larvae
Cliona sp. causes mortality to oyster larvae and deters
settlement
Conclusions (continued)

Clamworms (Neanthes succinea) are voracious predators
on oyster larvae; their bathwater also causes mortality



Oyster bathwater causes mortality to conspecifics


Average predation rate = ~11 larvae day-1 worm-1
Field population abundance = ~10,000 clamworms m-2
Effect significant after 2 days
Reef-associated invertebrates certainly influence settling
oyster larvae


Effect is not uniform or easily predictable
Interactions should inform the location and timing of shell
planting projects
Acknowledgements

VIMS – Eastern Shore Lab


VIMS – Gloucester Point


Roger Mann, John Brubaker, Missy
Southworth, Juli Harding,
Peter van Veld
UMD – CBL


Steph Bonniwell, Lynn Walker,
Heather Harwell, Edward Smith,
Roshell Brown, Alan Birch, Sean
Fate, Reade Bonniwell, Al Curry,
Jamie Wheatley, Linda Ward,
Summer Aides
Mario Tamburri
Funding

Kelley Watson Fellowship, Eastern
Shore Lab Research Grants, GSA
Mini-Grant, VIMS Assistantship