Potential Shellfish Aquaculture Potential Shellfish Aquaculture in Little Bay, New Hampshirein Little Bay, New Hampshire

REVISED January 18, 2012

Chris Nash and Carol ElliottNH Department of Environmental Services, Shellfish Program

Chris.Nash@des.nh.gov Carol.Elliott@des.nh.gov (603)-559-1509 (603)-559-1508

Why Focus on Little Bay?Why Focus on Little Bay?

Great Bay Research Reserve BoundaryGreat Bay Research Reserve BoundaryEelgrass Cover in Great BayEelgrass Cover in Great BayShellfish Harvest ClosuresShellfish Harvest Closures

Great Bay National Estuarine Great Bay National Estuarine Research Reserve BoundaryResearch Reserve Boundary

Restrictions on Restrictions on commercial aquaculture commercial aquaculture in the “core area” (south in the “core area” (south of the red line).of the red line).

Shellfish Harvest Closures

Bathymetry Suitable for Bathymetry Suitable for Bottom Oyster CultureBottom Oyster Culture

Mean low water to -5m 779 acres*Constraints include:– Existing farms– Eelgrass– Harvest closures– Mooring fields– Oil Spill response buoys

*Mapped by R. Grizzle and K. Ward at the University of New Hampshire

Current Aquaculture SitesCurrent Aquaculture Sites

Five licensed farms (~17 acres)

One upweller site

100m F&G buffer 100m F&G buffer between sitesbetween sites

Eelgrass CoverageEelgrass Coverage12-Year Occurrence12-Year Occurrence

Eelgrass CoverageEelgrass Coverage12-Year Occurrence12-Year Occurrence

Shellfish Areas Shellfish Areas Closed For HarvestClosed For Harvest

Multiple public health risk factors– wastewater treatment wastewater treatment

facilitiesfacilities– marinas, mooring fieldsmarinas, mooring fields– other pollution sources other pollution sources

Flexibility With Closed AreasFlexibility With Closed Areas

General Sullivan Bridge General Sullivan Bridge closureclosure– temporary closure until temporary closure until

construction Is completeconstruction Is complete– ~ 35 acres~ 35 acres

Marina and mooring Marina and mooring field areasfield areas– reduced closure zonesreduced closure zones

Mooring FieldsMooring Fields

No farms within an existing mooring fieldNo farms within an existing mooring field

150’ buffer zone150’ buffer zone– potential boat sewage riskpotential boat sewage risk– standard assumptions and calculationsstandard assumptions and calculations

Flexibility to resize buffersFlexibility to resize buffers

NHDES Spill Response BuoysNHDES Spill Response Buoys

50’ buffer zone to prevent 50’ buffer zone to prevent entanglementsentanglements

Revised Potential Aquaculture AreaRevised Potential Aquaculture Area

~389 acres eliminated~389 acres eliminated~ 17 acres in use~ 17 acres in use~ 396 acres available~ 396 acres availableMaximum aquaculture Maximum aquaculture area is ~413 acresarea is ~413 acres

How Many Aquaculture Sites FitHow Many Aquaculture Sites Fit Within This Area? Within This Area?

Hypothetical four-acre farm Hypothetical four-acre farm 50m buffer: 14.2 acres50m buffer: 14.2 acres36 (buffered) farms144 acres harvestable areaLikely an overestimate– depth, substrate, others

Assume unidentified constraints eliminate half of the 36 farms

How Many Oysters?How Many Oysters?One Age ClassOne Age Class

StageStageAssumedAssumed

MortalityMortalityOysters Per Oysters Per

AcreAcre

At Set OutAt Set Out ------ 750,000750,000

After First After First WinterWinter 60%60% 300,000300,000

Second YearSecond Year 30%30% 210,000210,000

Third YearThird Year 29%29% 149,100149,100

# Oysters on 4-Acre Farm# Oysters on 4-Acre FarmMultiple Age Classes on Four 1-acre SubplotsMultiple Age Classes on Four 1-acre Subplots

TypicalTypical

Four-Acre FarmFour-Acre Farm18 Four-Acre 18 Four-Acre

Farms*Farms*

OystersOysters

750,000 (yr 0)750,000 (yr 0)

300,000 (yr 1)300,000 (yr 1)

210,000 (yr 2)210,000 (yr 2)

149,100 (yr 3)149,100 (yr 3)

13,500,000 (yr 0)13,500,000 (yr 0)

5,400,000 (yr 1)5,400,000 (yr 1)

3,870,000 (yr 2)3,870,000 (yr 2)

2,683,800 (yr 3)2,683,800 (yr 3)

TotalTotal 1,409,100 oysters1,409,100 oysters 25,363,800 oysters25,363,800 oysters

* Half of the 36 possible farms; does not include 5 existing farms (17 acres)

Comparison to Comparison to Historical NumbersHistorical Numbers

1993: 24,000,000 harvestable-size oysters in Great Bay1993: 24,000,000 harvestable-size oysters in Great Bay

2008: 2,400,000 harvestable-size oysters in Great Bay 2008: 2,400,000 harvestable-size oysters in Great Bay

PREP Goal: 10,000,000 harvestable-size oysters PREP Goal: 10,000,000 harvestable-size oysters

Effects of Changing Farm SizeEffects of Changing Farm Size

Farm Farm Size Size

(acres)(acres)

FarmFarm

DimensionsDimensions50m Buffer 50m Buffer FootprintFootprint

Max. # Max. # Possible Possible

FarmsFarms

44 450’ x 390’450’ x 390’ 14 acres14 acres 3636

33 400’ x 330’400’ x 330’ 11 acres11 acres 6262

22 350’ x 250’350’ x 250’ 9 acres9 acres 8383

How Many Aquaculture Sites FitHow Many Aquaculture Sites Fit Within This Area? Within This Area?

Hypothetical Hypothetical three-acrethree-acre farm farm 50m buffer: 11 acres50m buffer: 11 acres62 (buffered) farms186 acres harvestable areaLikely an overestimate– depth, substrate, others

Assume unidentified constraints eliminate half of the 62 farms

# Oysters on 3-Acre Farm# Oysters on 3-Acre FarmMultiple Age Classes on Four 0.75 acre SubplotsMultiple Age Classes on Four 0.75 acre Subplots

TypicalTypical

Three-Acre FarmThree-Acre Farm31 Three-Acre 31 Three-Acre

Farms*Farms*

OystersOysters

562,500 (yr 0)562,500 (yr 0)

225,000 (yr 1)225,000 (yr 1)

157,500 (yr 2)157,500 (yr 2)

111,825 (yr 3)111,825 (yr 3)

17,437,500 (yr 0)17,437,500 (yr 0)

6,975,000 (yr 1)6,975,000 (yr 1)

4,882,500 (yr 2)4,882,500 (yr 2)

3,466,575 (yr 3)3,466,575 (yr 3)

TotalTotal 1,056,825 oysters1,056,825 oysters 32,761,575 oysters32,761,575 oysters

*Half of the 62 possible farms; does not include 5 existing farms (17 acres). Estimates assume Year 0 seeding rate of 750,000 juveniles/acre.

How Many Aquaculture Sites FitHow Many Aquaculture Sites Fit Within This Area? Within This Area?

Hypothetical Hypothetical two-acretwo-acre farm farm

50m buffer: 9 acres50m buffer: 9 acres

83 (buffered) farms

166 acres harvestable area

Likely an overestimate– depth, substrate, others

Assume unidentified constraints eliminate half of the 83 farms

# Oysters on 2-Acre Farm# Oysters on 2-Acre FarmMultiple Age Classes on Four 0.5 acre SubplotsMultiple Age Classes on Four 0.5 acre Subplots

TypicalTypical

Two-Acre FarmTwo-Acre Farm41 Two-Acre 41 Two-Acre

Farms*Farms*

OystersOysters

375,000 (yr 0)375,000 (yr 0)

150,000 (yr 1)150,000 (yr 1)

105,000 (yr 2)105,000 (yr 2)

74,550 (yr 3)74,550 (yr 3)

15,375,000 (yr 0)15,375,000 (yr 0)

6,150,000 (yr 1)6,150,000 (yr 1)

4,305,000 (yr 2)4,305,000 (yr 2)

3,056,550 (yr 3)3,056,550 (yr 3)

TotalTotal 704,550 oysters704,550 oysters 28,886,550 oysters28,886,550 oysters

*Half of the 83 possible farms; does not include 5 existing farms (17 acres).Estimates assume Year 0 seeding rate of 750,000 juveniles/acre.

ScenariosScenarios

Farm SizeFarm SizeNumber Number

of Farmsof Farms

Annual OysterAnnual Oyster

ProductionProduction

2 acres2 acres 20 - 4120 - 41 1.52 – 3.06 million1.52 – 3.06 million

3 acres3 acres 16 – 3116 – 31 1.73 - 3.47 million1.73 - 3.47 million

4 acres4 acres 9 – 189 – 18 1.34 – 2.68 million1.34 – 2.68 million

Low-end production estimates assume ¼ of the potential farms identified are licensed.High-end production estimates assume ½ of the potential farms identified are licensed.

Potential Market-Sized Annual Potential Market-Sized Annual Oyster ProductionOyster Production

0

500,000

1,000,000

1,500,000

2,000,000

2,500,000

3,000,000

3,500,000

2-AcFarms

3-AcFarms

4-AcFarms

High Est.

Low Est.

Upweller: Preferred ConditionsUpweller: Preferred Conditions

Salinity: 12-32 ppt Salinity: 12-32 ppt

Required Depth: 3–4 ftRequired Depth: 3–4 ft

Water Temp: > 50Water Temp: > 50°F °F

Nutrients: Influx of Nutrient-Rich WaterNutrients: Influx of Nutrient-Rich Water

Power Source Power Source

Stable AttachmentStable Attachment

Assumed Production of Assumed Production of Spat from UpwellersSpat from Upwellers

Assume each upweller produces 1.8 million juveniles from 2 Assume each upweller produces 1.8 million juveniles from 2 million seed each season. million seed each season.

Farm SizeFarm Size

(acres)(acres)

Estimated # SpatEstimated # Spat

Needed per YearNeeded per Year

EstimatedEstimated

# Upwellers# Upwellers

22 7.7 - 15.4 million7.7 - 15.4 million 5 - 95 - 9

33 8.7 - 17.4 million8.7 - 17.4 million 5 - 105 - 10

44 6.8 - 13.5 million6.8 - 13.5 million 4 - 84 - 8

Possible Upweller LocationsPossible Upweller Locations

Tidal Tributaries Where:Tidal Tributaries Where:– Salinity 10-34ppt Salinity 10-34ppt – Depth > 4 ftDepth > 4 ft– Power sourcePower source

Private residencesPrivate residences

WWTF OutfallsWWTF Outfalls

Possible Upweller LocationsPossible Upweller Locations

Little Bay Where:Little Bay Where:– Salinity 10-34ppt Salinity 10-34ppt – Depth > 4 ftDepth > 4 ft– Power SourcePower Source

MarinasMarinas

Private residencesPrivate residences