The University of MaineDigitalCommons@UMaine

Miscellaneous Publications Publications

4-2016

Oyster Environmental InteractionsCarter R. NewellPemaquid Oyster Company, musselsandoysters@gmail.com

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Repository CitationNewell, Carter R., "Oyster Environmental Interactions" (2016). Miscellaneous Publications. 9.https://digitalcommons.library.umaine.edu/ari_miscpubs/9

Oyster environmental interactions

Newell, C.R. Ph.D. Maine Shellfish R&D, Damariscotta, School of Marine Sciences, University of Maine, Pemaquid

Oyster Company, Pemaquid Mussel Farms

How do coastal ecosystems affect the growth rates of Crassostrea virginica on

seafarms?

How do populations of Crassostrea virginica

affect coastal ecosystems?

Understanding the Productivity of the Damariscotta River April 1, 2016 DRA

11 miles

The Damariscotta River Estuary and locations of

monitoring buoys

oysters

Oyster farming processes site selection, hatchery, upwellers, nursery,

grow-out, processing, harvesting, sales.

• RIGHT SPECIES

• RIGHT ENVIRONMENT

• RIGHT CULTURE TECHNOLOGY

• RIGHT MARKET PRICE

• ENVIRONMENTAL STEWARDSHIP

What makes aquaculture successful?

What factors can threaten it?

• EXPOSURE TO WAVES FROM BIG STORMS

• BACTERIAL POLLUTION (RAINFALL, NON-POINT

SOURCE, POINT SOURCE)

• RED TIDES

• VIBRIO OUTBREAKS

• DISEASE AND MORTALITY

• PREDATION

Oysters $5 to $10 million and growing

Mussels $1 to $2 million and growing

Maine currently leases about 600

acres to all shellfish farms in the state

Scales of Interactions

The estuary • Geomorphology - water depth, PAR, water residence times,

fresh water input, nutrient sources, exposure to waves, physical oceanography

The bay • Productivity – PAR and nutrients, seasonal and tidal effects,

weather events, grazing, water flow patterns, resuspension The farm • Food supply and demand, oyster biomass, aquaculture structure

(suspended, bottom), husbandry The oyster • Local food availability as a function of stocking density, particle

concentration and quality, hydrodynamics

0

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ch

l a

(u

g l

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15% reduction in chl a over an oyster farm (2010) depth (ft)

center lease

control

Ecosystem interactions

• Phytoplankton biomass • Sedimentation of biodeposits • Light penetration • Nutrient regeneration and

nutrient removal • Benthic and pelagic habitat for

invertebrates, fish and birds • Benthic diatom populations • Restoration of wild populations

American oyster growth drivers

• Water temperature: filtration rate, food assimilation rate, rate of shell growth, reproduction (20-30° C)

• Water salinity: filtration rates (18-32 psu) • Particle size (> 2 µm), type (inorganic, organic),

concentration • Food quality: phytoplankton (diatoms,

dinoflagellates, ciliates, microflagellates); detritus (phytodetritus, macroalgal detritus) detritus quality (digestibility, N/C ratio)

• Water velocity: ( for populations)

Environmental Growth Drivers and Ecosystem Interactions

With UDSA and MAIC funding we have developed an oyster GIS system

• Site selection for sustainable seafarms

• Improve husbandry practices and profitability (growth rate and yield)

• Understand aquaculture/environment and human interactions

ShellGIS Workspace

Data layers (50 m grid)

Flow model out put

Water quality data

Static layers

Models

SHELLSIM growth model

Benthic boundary layer particle and nutrient exchange algorithms

Suspension culture particle and nutrient exchange algorithms

Hydraulic zone of influence

Economic models

Benthic biodeposition and nutrient regeneration

(coming soon!)

System architecture shellgis.com Based on STEM-GIS platform developed by Discovery Software Ltd. UK x, y, z, time dimensions

Factors affecting utility and functionality of GIS system

Data and models • Hydrodynamic flow model (Mike 21,

FVCOM) Bathymetry, tide gauge and water velocity field measurements

• Shellfish growth model (ShellSIM) species calibration (ecophysiology) in-situ • Water quality data: how it varies

temporally and spatially within the bay and the farm

User interface • For growers: what species, what type of

culture, where, seed size, density, time of year: growth rates, yield, profit

• For scientists: how animals respond to changing environments, model functional responses such as clearance rates, oxygen consumption, ammonium excretion, biodeposition, growth, and reproduction

• For regulators: (coming soon) ecosystem services, benthic impacts and nutrient regeneration

Measured and modeled oyster growth based on field measures of oyster responses to

environmental conditions (food quality)

Absorption of food particles Food availability, measured and modeled growth using ShellSIM

Model results: oysters grow faster in warmer water, in fast moving water, and each place has an optimal stocking density

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Oyster live weight for different bottom densities (no. m-2) 50

200

400

600

1000

At one location (click on

map)

For whole bay (% reduction in

growth) at 2 bottom

densities

100 oysters m-2 500 oysters m-2

Effects of temperature (+/- 5ºC)

Effects of density (bottom culture)

How can we improve our understanding of oyster/ecosystem interactions? Better data on growth drivers : CTD transects and water samples

Student transects

0.000.501.001.502.002.503.003.504.004.505.00

Mean chl a all profiles Aug - Nov, 2015

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Aug27

Sep11

Oct6

Oct23

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Mean Chl a from CTD casts Damariscotta River August -

November, 2015

Upper river

Perkins Pt

Glidden ledges

Darling Center

S Bristol

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Aug27

Sept11

Oct6

Oct23

Nov10

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Mean temperature CTD profiles Damariscotta River

Aug - Nov 2015

Upper river

Perkins Pt

Glidden ledges

Darling Center

S Bristol

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Oct 6 Oct 23 Nov 10 Nov 23

Salinity Aug - Nov 2015 Damariscotta

Upper river

Perkins Pt

Glidden ledges

Darling Center

S Bristol0

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Upperriver

Perkins Pt DarlingCenter

S Bristol

Suspended particulate matter mg l-1

TPM

PIM

POM

% POM

How can we improve our understanding of oyster/ecosystem interactions? Water samples

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Perkins Pt DarlingCenter

S Bristol

Mean primary production rate

Avg Pmax (µg C L-1 d-1)

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Perkins Pt Darling Center S Bristol

Mean POC (ug/l) at Buoy Stations

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Mean PON (ug/l) at Buoy Stations

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Picoeukaryote cells ml-1 Aug 27 - Nov 23

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Nitrate (uM)

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23-Nov-150

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Perkins Pt DarlingCenter

S Bristol

Ammonium (uM)

Understand the productivity of the Damariscotta River April 1, 2016 DRA

How does this compare with other places? Three estuaries cruises in 1993-1994

The Damariscotta River is much more efficient at converting nutrients to phytoplankton than the

Sheepscot and Kennebec (plot from Dr. Larry Mayer)

Copepod – Eurytemora herdmani

Copepod – Acartia hudsonica

Barnacle and bivalve larvae

Mysid shrimp – Neomysis americana

Cladoceran – Evadne nordmanni

Polychaete larvae

Copepod nauplii

How can we improve our understanding of oyster/ecosystem interactions? Vertical

zooplankton tows (they also feed on phytoplankton)

How can we improve our understanding of

oyster/ecosystem interactions? LOBO buoys

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CD

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(Q

SDE)

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ity

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)

Time (hourly samples)

CDOM and Salinity Sep 25 to Nov 2, 2015

CDOM LOBO 1

Salinity LOBO 1

CDOM LOBO 2

Salinity LOBO 2

7.6

7.65

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7.75

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Time (hourly samples)

pH September 25 to October 14

pH LOBO 1

pH LOBO 2

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Quenching of Chl a (Sept 25-Oct 4, LOBO 2)

chlorophyll [ug/L]

Log (PAR)

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Chl a, transmission and turbidity Sep 25 to Oct 3 LOBO 1

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Chl a, transmission and turbidity Sep 25 to Oct 3 LOBO 2

How can we improve our understanding of oyster/ecosystem interactions? Buoys and weather stations

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Time (hourly samples)

Chl a and nitrate Sept 25 to Oct 14 (nitrate not adjusted for offset)

chlorophyll[ug/L] 1

nitrate [uM] 1

chlorophyll[ug/L] 2

nitrate [uM] 2

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Solar radiation at the DRA at Salt Bay http://rainwise.net/weather/DRA04543

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MaineMay

MaineJuly

MarylandAugust

Total particulate matter per oyster d-1

Feces TPMmg d-1

PseudoTPM mg d-1

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MaineJuly

MarylandAugust

Measured (Maine) and modeled biodeposition

(ShellSIM, Maryland)

Temperature°C

Total carbon mgd-1

Chl a SPM POM PIM Temp Sal DO

ug l-1 mg l-1 mg l-1 mg l-1 C ppt mg l-1

31.39 37.38 5.91 31.37 30.12 9.30 7.12

Maryland conditions in August

Model and field data: benthic biodeposition In July in Maine, a million mature oysters removes 400 kg TPM

per day and repackages it into biodeposits

• Maryland farm biodeposition settles quickly to bottom and mostly moved as bedload due to resuspension from tidal currents and waves

• Most of the nitrogen is converted back to ammonium for the phytoplankton to use within days, affecting the Bay Scale nutrient budget for phytoplankton

*Testa, J.M, D.C. Brady, J.C. Cornwell, M.S. Owens, L.P. Sanford, M.S. Owens, L.P. Sanford, C.R. Newell, S.E. Suttles and R.I.E. Newell. 2015. Modeling the impact of floating oyster aquaculture on sediment-water nutrient and oxygen fluxes. Aquaculture Environment Interactions 7:205-222.

Biodeposition continued:What happens to it?* In both Maine and Maryland, shellfish biodeposition is about 2x background deposition but at these sites with tidal flow > 35 cm s-1 most is moved off site and converted into ammonium within a couple of days (recycling)

Oyster, mussel and tunicate biodeposits settle at .2-2 cm s-1

0 1 10

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Biodeposit ESD (mm)

Green – Area where current induced erosion rate exceeds deposition rate

Yellow – Area with wave induced resuspension using SWAN wave model and water depth

Maryland site: high loadings, shallow water but tidal resuspension and periodic wave resuspension

The farm sediments are easily eroded

Biodeposition continued: the importance of erosion Every site is different but in general, higher water velocity allows for greater farm productivity as well as better nutrient recycling efficiency and minimal benthic impact

45th Benthic Ecology Meeting March 2016 Portland Maine

What have we learned?

• Estuarine geomorphology results in longer residence times in the upper estuary, where it is shallow and sufficient light and nutrients for phytoplankton to grow, increasing primary productivity. Fort Island Narrows and Glidden Ledges contribute significantly to the productivity in the Damariscotta River.

• The upper estuary also has higher suspended particulate matter and detritus concentrations

• Water temperature is higher in the upper estuary, allowing for higher filtration rates and rapid growth of oysters

• Rainfall events result in lower salinity, higher CDOM, higher nutrients and lower pH in the upper estuary.

• There are significant seasonal and tidal variations in all parameters • Nitrate concentrations are lower in the upper estuary but ammonium concentrations

remain high throughout the season • Oyster biodeposition increases with water temperature, phytoplankton concentrations

and suspended particulate matter but hydrodynamic factors control its dispersion • Oyster farms act to concentrate, remove and recycle nutrients in the estuary and

have beneficial ecosystem interactions

• The farms act as biological reefs, attracting seaweed, invertebrates, fish and birds • A Shellfish GIS system may be used to quantify aquaculture/environment interactions

and improve husbandry practices

Why is it worth it?

• Recognize and quantify the value of estuaries as food growing areas • Understand what makes estuaries productive and how they change under

different environments (i.e. increased temperatures and precipitation, pH) • Quantify ecosystem services of bivalves • Choose and manage sites based on their suitability and sustainability • Evolve from trial and error aquaculture to sustainable economic development • Improve engineering of aquaculture structures and placement in estuaries

They taste good!

What else can we do? Reduce cost of modeling and data collection , make it widely

available for stakeholders (web based), and user friendly Develop simple models of estuarine productivity

Advocate for and protect clean water

Temp, sal, PAR, chl a shellfish growth basket, wifi

Coastal Observation Buoy (COB) Prescott, Newell, Davis 2016 $2500 Frequently asked questions

Water column effects of a small farm

Human interactions: Pemaquid Oyster Festival

Last Sunday in September – see you there!

• Shuck 15,000 oysters • Raise $15,000 for Ed Myers

marine conservation fund • Over $100,000 to date

• Boat tours of oyster farms • Shucking contest • Live music all day

• Tent of education/information including land trusts, conservation groups, regulators, research, touch

tank, children's activities

Acknowledgements

www.shellgis.com