Southeast Watershed Alliance Symposium
Portsmouth, New Hampshire, 11 May 2011
Oyster Restoration, Aquaculture, and
Bioextraction in New Hampshire
Ray Grizzle
Jackson Estuarine Laboratory & Department of Biological Sciences
University of New Hampshire, ray.grizzle@unh.edu, http://oyster.unh.edu
Presentation Overview
• Status of natural oyster populations
• Restoration of natural reefs
• The aquaculture/restoration connection
• Oyster farming in New Hampshire
• Nitrogen bioextraction by farmed oysters
Status of Natural Oyster Populations
(Data from NH Fish & Game Department; graphics from Phil Trowbridge, PREP)
The 2006 Recruitment
General Oyster Reef Restoration Protocol in NH
• Identify restoration site: site survey, consultations
with stakeholders, etc.
• Design restoration project: shell “planting,” remote
setting/spat-on-shell production, nursery grow-out,
“spat seeding,”
• Secure permits from relevant regulatory agencies
• Purchase, arrange for delivery of needed materials:
dead mollusc shells, oyster larvae, etc.
• Secure contracts with marine construction company,
other subcontractors
• Do restoration work (if you have time/energy/$ left)…
General Oyster Reef Restoration Protocol in NH
(1) Construct reef base using dead/seasoned mollusc shell:
• 100% cover of 1 acre requires ~100 yd3 of shell minimum
• Subcontract to marine construction company typically required
• General method shown above
General Oyster Reef Restoration Protocol in NH
(2) “Seed” reef base with spat-on-shell from remote setting of oyster larvae
Summary of NH Oyster
Restoration Projects
Restoration Site, Size
Restoration Methods
Salmon Falls River, 0.1 acre adult transfer, spat-on-shell
South Mill Pond, 0.05 acre
adult transfer, spat-on-shell
Success Metrics
Last
Observation
Date
General Condition at Last Sampling
2000
shellfish density & size;
water filtration
2007
high oyster density from 2006 natural
spat set
2001
shellfish density & size;
water filtration
2007
~100% mortality of mussels and oyster
Species Involved
Construction
Date
Crassostrea virginica
Crassostrea virginica;
Mytilus edulis
Adams Point (Great Bay),
0.05 acre
gravel base, spat-on-shell
Crassostrea virginica
2003
shellfish density & size
2006
heavy silt accumulation; ~100% oyster
mortality
Nannie Island (Great Bay),
2.5 acres
gravel base, spat-on-shell
Crassostrea virginica
2004
shellfish density & size
2006
high oyster density from 2006 natural spat
set
Bellamy River, 1.55 acres
adult transfer, spat-on-shell
Crassostrea virginica;
Mytilus edulis
2005 - 2007
shellfish density & size
2008
moderate oyster density from 2006 natural
spat set; 100% mussel mortality
Crassostrea virginica
2007
shellfish density & size;
resident plants and
animals
2009
~80% spat mortality; high density from 2006
natural spat set
Crassostrea virginica
2009
shellfish density & size
2009
substantial 2009 natural spat set
2009
high spat mortality
Nannie Island (Great Bay),
1.5 acres
spat-on-shell
Oyster River (TNC), 0.2 acre shell planting, spat-on-shell
shell planting, spat-on-shell
Crassostrea virginica
2009
shellfish density & size;
water filtration;
associated animals
Oyster River (TNC), 1.0 acre shell planting, spat-on-shell
Crassostrea virginica
2010
shellfish density & size
2010
(early post-construction obersations only)
Berry's Brook, 1.0 acre
Oyster River (NRCS/GSS),
1.0 acre
shell planting, spat-on-shell
Crassostrea virginica
2010
shellfish density & size
2010
(early post-construction obersations only)
Little Bay (NRCS/LBOC),
1.0 acre
shell planting, spat-on-shell
Crassostrea virginica
2010
shellfish density & size
2010
(early post-construction obersations only)
HISTORIC Funding Sources for
Oyster Restoration
• Piscataqua Region Estuaries Partnership
• US Environmental Protection Agency
• National Oceanic & Atmospheric Admin.
• Cooperative Institute for Coastal and Estuarine
Environmental Technology
• National Estuarine Research Reserve System
• New Hampshire Sea Grant
• The Nature Conservancy
• City of Dover
• Natural Resources Conservation Service
The Aquaculture/Restoration Connection
• Rationale: oyster farmers know how to
raise oysters…
• USDA/NRCS funded restoration of 3
acres of bottom area in NH in 2010;
a 0.5-acre project is scheduled for 2011
• The future?
Existing Oyster Farms in New Hampshire
Determining the Potential for Expansion
of Oyster Aquaculture in New Hampshire
• Secure maps or data needed to produce maps
• Produce maps of major factors affecting shellfish farming
• Interview stakeholders
• Assess all relevant environmental information in
context of social factors
• Assist prospective farmers
• Interface with regulatory and management agencies
Mapping the Major Factors
Maximum PSP toxicity values in estuary
Bathymetry, eelgrass, shellfish closures
Interpreting the Maps
• Map overlay method
assesses multiple factors
• Potential aquaculture
areas = adequate depth
+ open for harvesting
+ no eelgrass
(+ or - other factors)
Nitrogen bioextraction by farmed oysters
•Two age/size classes (0 year,
1 year) deployed at 6 sites
•Deployed off-bottom in
oyster bags typical for NE
•Variables: shell height, soft tissue DW, %N, %C
•CHN/O elemental analyzer (USEPA, Narragansett, RI)
•ANOVAs on dependent variables
Results
Results
Soft Tissue
Shell Height
(mm)
Shell DW Soft Tissue DW
(g)
(g)
Shell
Whole Oyster
%C
%N
%C
%N
Total C (g)
Total N (g)
Source
7.8
n/d
0.03
32.1
7.71
n/d
n/d
n/d
n/d
Present study
12.7
n/d
0.20
37.6
9.10
n/d
n/d
n/d
n/d
Present study
35.7
n/d
0.06
27.6
6.52
n/d
n/d
0.585*
0.013*
Present study
55.6
n/d
0.24
32.9
7.86
n/d
n/d
3.082*
0.065*
Present study
76
150
1
n/d
7
n/d
0.3
n/d
0.52
Newell et al. 2005
43.6
4.8
0.20
43.30
8.15
11.8
0.18
0.647
0.025
Higgins et al. 2011
64.8
24.3
0.80
44.30
8.06
12.4
0.19
3.391
0.112
Higgins et al. 2011
85.5
37.6
1.58
45.10
7.28
12.4
0.17
5.375
0.176
Higgins et al. 2011
117.8
71.9
3.00
46.20
7.37
12
0.26
10.011
0.394
Higgins et al. 2011
Some ‘what/if’ Scenarios
Today:
• 10 acres, 200,000 oysters/ac/yr, 0.3 g N/oyster:
0.67 ton N
The Future?:
• 50 acres  3.4 tons N/yr
•
100 acres  6.8 tons N/yr
What factors are involved in estimating the nitrogen
bioextraction potential for farmed oysters in NH?
Present:
• Three farms, <100,000 oysters sold in 2010
Future:
• How many farms can be permitted in NH?
• What is maximum farm production?
• How do we accurately quantify bioextraction?
• What role(s) should oyster farming play?
Next Steps
2011/2012 USEPA-funded study
• 1-yr deployment, multiple sites, etc.
2012 Completion of NOAA/NMFS-funded study
• Assessment of shellfish aquaculture expansion
potential
Ongoing management/regulatory process
• ?????