Evaluation of shellfish aquaculture and
nutrient removal and credit trading in
Long Island Sound
Suzanne Bricker
NOAA National Ocean Service
Joao Ferreira
IMAR
Katharine Wellman
Northern Economics
Gary Wikfors
NOAA National Marine Fisheries Service
Mark Tedesco
EPA Long Island Sound Study
Julie Rose
NOAA National Marine Fisheries Service
Bob Rheault
East Coast Shellfish Growers Association
Robin Landeck Miller HydroQual
Paul Mankiewicz
The Gaia Institute
Estuarine & Coastal Sciences Association: ECSA47 Symposium
Figueira da Foz, Portugal
September 14-19, 2010
Long Island Sound: Background
New York
Connecticut
Size: 3,259 km2
Tide: 2 m in west, 1 m in east
Residence time: 2-3 months
Highly developed watershed
Population: 4.9 x 106 total, 1,508 people/km2
2/3 freshwater inflow from Connecticut River
The Long Island Sound Study names 4 major water quality
issues being addressed by government agencies,
environmental groups, universities and the private sector:
•
•
•
•
Nutrients and hypoxia - eutrophication
Toxic Contaminants and pollution
Pathogens
Floatable debris
EPA Regional Ecosystem Services Program–
Eutrophication and shellfish aquaculture
 Two year project, EPA funded, focus on Long Island Sound and Great
Bay/Piscataqua region;
 Research groups from NOAA, EPA, HydroQual Inc., Longline
Environment Ltd., Northern Economics, Shellfish Environmental
Services;
 Conduct a comparative study on the bioextraction potential of
shellfish, and its contribution to ecosystem services;
 Species: Eastern oyster, Northern quahog, ribbed mussel;
 For Long Island Sound (major case study): combine watershed
models, detailed water quality models (SWEM), EcoWin2000, FARM, and
economic models.
LIS Eutrophication Impacts
Loss of eelgrass from historic range
Hypoxia
Species shifts
(Picture or explanation?)
NEEA/ASSETS Results: LIS Highly Eutrophic
Since early 1990s:
Nuisance/toxic blooms improved
Macroalgae improved
Chl no change
SAV no change
DO worsened
Bricker et al. 2007, Nutrient enrichment in
the nation`s estuaries, A decade of change. National
Estuarine Europhication Assessment Update.
www.eutro.us
Potential Resolution of Nutrient issues:
Long Island Sound TMDL*
(Approved by EPA April 2001)

In-basin Nitrogen Reduction Goal
– 58.5% by 2014
• 10% reduction to urban and agricultural runoff
• 59-64% reduction to point sources


Allows “Trading” of nutrient credits
Out-of-basin Actions
– Out of State Sources (10% reduction to runoff, 25%
reduction to point sources)
– Atmospheric Deposition (Clean Air Act reductions)

Alternatives to nutrient control
– Biomass harvesting

Periodic Revision (Adaptive Management)
– Evaluation in 2008
*Total Maximum Daily Load
Potential Resolution of Nutrient issues:
nutrient bioextraction considered for LIS

Longtime nitrogen management focus has been point
sources (i.e. wastewater treatment plant upgrades)

Growing recognition that non-point source pollution is
also a substantial (more difficult) problem

Nutrient bioextraction can also address legacy pollution
in the water column and sediments
International Workshop on Bioextractive Technologies for Nutrient Remediation
December 3-4, 2009 at UConn Stamford
How does bioextraction work?
• Cultivation and harvest of shellfish and macroalgae
• Nutrients are taken up directly (seaweed) or indirectly
(shellfish, via plankton, organic detritus)
• Removal of biomass removes nutrients from the
ecosystem
• Removal of 1ary eutrophication symptoms reduces 2ary
symptoms by (i) improving water clarity, restoring SAV;
(ii) limiting D.O. loss from decomposition of organic
matter
• Shellfish farmers can negotiate nutrient credits to offset
loading fom land, and be included in the trading program
Scope of shellfish aquaculture:
American Oyster (Crassostrea virginica), Northern Quahog clam (Mercenaria mercenaria)
Harvest – Bottom Culture
Shellfish lease area
LIS Hard Clam harvest
20 kT
600000
C T Harves t
State
Approved
NY
84
0.2
16
489
CT
51
31
18
444
NY/CT
68
15
17
934
NY Harves t
Restricted Prohibited Total
as % total area
103 acres
400000
200000
0
1980
1985
1990
1995
2000
2005
2010
LIS Oyster Harvest (NY+CT)
27 kT
1200000
900000
NY
only
600000
300000
0
1980
1985
1990
1995
2000
2005
2010
Millions of D ollare
LIS Oyster Harvest Value
50
40
30
20
10
0
1980
Approved for CT includes conditionally approved, for
NY Approved is represented by Certified and
Restricted is represented by Seasonal rating.
Prohibited (CT) and Uncertified (NY) are considered
equal.
On the basis of a yield of 10 tonnes ha-1 (1 kg m-2), the
reported harvest of ~17,000 tonnes (37 million lb)
would correspond to 17 km2, i.e. ~4200 acres
1985
1990
1995
2000
2005
2010
The REServ approach
Field
measurements
Farm-scale
modelling
FARM model
System- and localscale ecological
modelling
E2K, FARM, ASSETS
System-scale
ecological modelling
Economic model
Millennium
Ecosystem
Assessment
Framework
Catchment
model
SPARROW,
Watershed
Runoff
Modelling
SWEM, E2K, ASSETS
Transport
model
Public
participation
Individual growth models
for cultivated species
Ribbed mussel
SWEM
In situ and lab
experiments
Preliminary simulations of biomass harvesting
show substantial DO improvements
System-Wide Eutrophication
model (SWEM)
HydroQual, 2009.
Model year simulation: 1988
Delta min.D.O (mg L-1)
Minimum D.O (mg L-1)
Phase 3 & 4 TMDL: N & Corg
4.0
3.0
2.0
1.0
With shellfish
and seaweeds
0.0
+4.0
+2.0
0.0
-2.0
-4.0
Change in dissolved oxygen
through the use of IMTA
Data Drivers for simulated farm
Simulated farm location is within
approved lease areas
Data for Station 09 for 2008
Thanks to Matt Lyman of CTDEP
Simulated farm location from CTDEP
aquaculture bottom lease maps and CTDEP
data for station 09 for drivers of FARM
Salinity
Water temperature (deg C)
30
25
20
15
10
5
0
28
26
24
22
J
F
M A
M J
J
A
S
O
N
D
J
F
M
A
M
J
J
A
S
O
N
D
Data Drivers for FARM model application
Station 09 for 2008
Particulate carbon (mg/l)
Dissolved oxygen (mg/l)
1.0
15
10
0.5
5
0.0
0
J
F
M
A
M
J
J
A
S
O
N
J
D
F
M
TSS (mg/l)
A
M
J
J
A
S
O
N
D
O
N
D
Chlorophyll (ug/l)
25
20
15
10
5
0
40
30
20
10
0
J
F
M
A
M
J
J
A
S
O
N
D
J
F
M
A
M
J
J
A
S
Preliminary FARM model results
Total N load to LIS = 50 x103 t y-1
Summary and Conclusions
• Biomass harvesting –
• promising solution to nutrient issues
• complementary to land-based nutrient load reductions
• provides shellfish product, income for shellfish farmers
• caveat: marine spatial planning
• Significance to LIS nutrient budget not known but • 45 tons N removed in one 10 hectare farm (PEQ 13,600)
• Shellfish cultivation in 3% LIS area would remove
equivalent of present N load
• If significant, will shellfish farmers become part of the LIS
nutrient trading program?
• Stay tuned
Try the models yourself:
FARM
www.farmscale.org
ASSETS
www.eutro.org/register