North CapeNorth Cape Scallop Restoration ProjectScallop Restoration Project

Lessons learned from the restoration efforts in Lessons learned from the restoration efforts in Rhode Island’s south county salt pondsRhode Island’s south county salt ponds

Boze Hancock1, James Turek2, Najih Lazar3, and John Catena4

1Coordinator, North Cape Shellfish Restoration Program, Narragansett, RI2NOAA Restoration Center, Narragansett, RI

3RIDEM Division of Fish and Wildlife, Jamestown, RI4NOAA Restoration Center, Gloucester, MA

Grounding of the North Cape, January 1996

828,000 Gallons of No. 2 Fuel Oil Released to Block Island Sound

‘‘North Cape’ RestorationNorth Cape’ Restoration

Damages settlement in 2000Damages settlement in 2000

Shellfish Restoration one of several programsShellfish Restoration one of several programsto compensate for 150 million lost bivalvesto compensate for 150 million lost bivalves

Shellfish Restoration program began in 2002Shellfish Restoration program began in 2002Coordinator (Karin Tammi, 2002-2003; Coordinator (Karin Tammi, 2002-2003;

Boze Hancock,2004 – present) Boze Hancock,2004 – present)Assistant & 4 to 6 staff and students annuallyAssistant & 4 to 6 staff and students annually

Project completion expected 2007Project completion expected 2007

North Cape Shellfish Restoration Program

Aim

To restore lost biomass and ecological functions by establishing

and enhancing sustainable shellfish populations.

Target speciesBay scallop Argopecten irradians, restoration

Eastern oyster Crassostrea virginica, restoration

Quahog Mercenaria mercenaria, enhancement

South County salt ponds

Scallop restorationScallop restoration

2 phases; Direct seeding2 phases; Direct seeding Caged spawner sanctuary Caged spawner sanctuary

Phase 1, Direct seeding 2002 & 2003Phase 1, Direct seeding 2002 & 2003 Large scale seeding of 25 – 35 mm hatchery Large scale seeding of 25 – 35 mm hatchery

produced stock, fall of 1produced stock, fall of 1stst growing season growing seasonProvide broodstock for next breeding seasonProvide broodstock for next breeding season

Capture of spat for subsequent re-stocking of other Capture of spat for subsequent re-stocking of other ponds using ‘spat bags’ponds using ‘spat bags’

Dive surveys to monitor survivalDive surveys to monitor survival

North Cape Scallop Restoration ProjectDirect seeding of broodstock

Release sites, based on habitat assessments

Scallop direct seedingScallop direct seeding

20022002Point Judith PondPoint Judith Pond 680,000680,000

20032003Potter PondPotter Pond 286,300286,300Greenhill PondGreenhill Pond 188,980188,980Ninigret PondNinigret Pond 581,090581,090Quonochontaug PondQuonochontaug Pond 1,029,840 1,029,840

TotalTotal 2,766,200 2,766,200

Ninigret Pond; Release areas and indicating strata used for random transect surveys of scallop abundance

Results, AbundanceNinigret Pond ~ 10,000Quonochontaug Pond < 1,000Green Hill Pond ~ 0Potter Pond ~ 0Pt. Judith Pond 0

North Cape Scallop Restoration ProjectDirect seeding of broodstock - release sites

Phase 2 – Spawner sanctuary from 2004Phase 2 – Spawner sanctuary from 2004

3 components3 components

Broodstock cagesBroodstock cages

Maximize reproductive output by protecting broodstock Maximize reproductive output by protecting broodstock

Ninigret Pond 2004 to 2005, Quonochontaug Pond 2006 Ninigret Pond 2004 to 2005, Quonochontaug Pond 2006

Hatchery produced broodstock Hatchery produced broodstock

10,000 to 20,000 10,000 to 20,000 Settlement of larvae monitored using ‘spat bag arrays’Settlement of larvae monitored using ‘spat bag arrays’

4 array locations per pond4 array locations per pondSix bags / line, Retrieved every 4 weeks, 2 week overlapSix bags / line, Retrieved every 4 weeks, 2 week overlap

Annual diver surveys to estimate abundance, Annual diver surveys to estimate abundance, (Survival of spat to maturity), (Survival of spat to maturity),

Spawner sanctuaryMature broodstockMaintained in cages

for protection from predators

Spat Bag array

Schematic

Field example

FreeScallops

Ninigret Pond 2004 to 2006

Spawner cages10,000 broodstock 04 & 05

Spat bag arraysSame structure each year4 sites, 6 bags, 8 collections

Settlement indexΣ mean spat per bag

Dive surveys2004, 88 transects (6 strata)2005, 36 transects (3 strata- west basin)2006, 80 transects (6 strata)

2004, # Broodstock ~ 20,000 10,000 free (SE 5,500)

10,000 caged

Settlement Index32

2005, # Broodstock ~ 142,000 132,000 free (SE 55,000)

10,000 caged

Settlement Index137

2006, # Broodstock ~ 210,000 210,000 free (SE 102,000)

0 caged

Settlement Index35 + ?

Mean spat per bag from Ninigret Pond 2005

0.0

10.0

20.0

30.0

40.0

50.0

60.0

13 Jul2005

26 Jul2005

11 Aug2005

23 Aug2005

9 Sep2005

27 Sep2005

18 Oct2005

15 Nov2005

Collection date

Me

an

sp

at

pe

r b

ag

West End

Hall Point

Breachway

Aqualease

Mean spat per bag from Ninigret Pond 2004

0.0

10.0

20.0

30.0

40.0

50.0

60.0

13 Jul2004

26 Jul2004

11 Aug2004

24 Aug2004

7 Sep2004

22 Sep2004

5 Oct2004

2 Nov2004

Collection date

Me

an

sp

at

pe

r b

ag

West End

Hall Point

Breachway

Aqualease

Mean spat per bag from Ninigret Pond 2006

0.0

10.0

20.0

30.0

40.0

50.0

60.0

26 Jul2006

8 Aug2006

23 Aug2006

8 Sep2006

19 Sep2006

4 Oct2006

26 Oct2006

15 Nov2006

Collection Date

Me

an

sp

at

pe

r b

ag

West End

Hall Point

Breachway

Aqualease

?

Summary – Ninigret PondSummary – Ninigret Pond -04 and -05 results very encouraging-04 and -05 results very encouraging -06 results more difficult to interpret-06 results more difficult to interpret

Broodstock only in western basinBroodstock only in western basinSettlement only in central basinSettlement only in central basin

(larval transport / asymmetric survival)(larval transport / asymmetric survival)

Environmental conditions extreme in 06Environmental conditions extreme in 06Wettest year on recordWettest year on recordLow salinity (16 to 27 ppt), stable stratification,Low salinity (16 to 27 ppt), stable stratification,

evidence of anoxiaevidence of anoxiaMassive kill of scallops in central & northern basins Massive kill of scallops in central & northern basins

Quonochontaug PondQuonochontaug Pond

Similar design to Ninigret PondSimilar design to Ninigret PondSpawner sanctuarySpawner sanctuarySettlement surveysSettlement surveysMonitoring broodstock abundanceMonitoring broodstock abundance

2006, # Broodstock ~ 20,000

~ 400 free20,000 caged

Mean spat per bag from Quonochontaug Pond 2006

0.0

10.0

20.0

30.0

40.0

50.0

60.0

17 Aug2006

30 Aug2006

12 Sep2006

26 Sep2006

12 Oct2006

30 Oct2006

? Nov2006

Collection date

Mea

n sp

at p

er b

ag

West End

Spawner Sanctuary

Bill's Island

East End

?

ConclusionsConclusions Due to high predation rates, direct seeding of Due to high predation rates, direct seeding of

scallops was not a productive restoration methodscallops was not a productive restoration method Caged spawner sanctuary with relatively few Caged spawner sanctuary with relatively few

broodstock has been cost effective.broodstock has been cost effective.Produced appreciable spatfalls and population Produced appreciable spatfalls and population increasesincreases

Water quality. High flushing rates may reduce Water quality. High flushing rates may reduce likelihood of anoxic eventslikelihood of anoxic events

Benefit from a long term project commitmentBenefit from a long term project commitment