North Cape Scallop Restoration Project Lessons learned from the restoration efforts in Rhode Island’s south county salt ponds Boze Hancock 1, James Turek 2, Najih Lazar 3, and John Catena 4 1 Coordinator, North Cape Shellfish Restoration Program, Narragansett, RI 2 NOAA Restoration Center, Narragansett, RI 3 RIDEM Division of Fish and Wildlife, Jamestown, RI 4 NOAA Restoration Center, Gloucester, MA

Grounding of the North Cape, January ,000 Gallons of No. 2 Fuel Oil Released to Block Island Sound

‘North Cape’ Restoration Damages settlement in 2000 Damages settlement in 2000 Shellfish Restoration one of several programs to compensate for 150 million lost bivalves Shellfish Restoration one of several programs to compensate for 150 million lost bivalves Shellfish Restoration program began in 2002 Coordinator (Karin Tammi, ; Boze Hancock,2004 – present) Assistant & 4 to 6 staff and students annually Shellfish Restoration program began in 2002 Coordinator (Karin Tammi, ; Boze Hancock,2004 – present) Assistant & 4 to 6 staff and students annually Project completion expected 2007 Project completion expected 2007

North Cape Shellfish Restoration Program Aim To restore lost biomass and ecological functions by establishing and enhancing sustainable shellfish populations. Target species Bay scallop Argopecten irradians, restoration Eastern oyster Crassostrea virginica, restoration Quahog Mercenaria mercenaria, enhancement

South County salt ponds

Scallop restoration 2 phases; Direct seeding Caged spawner sanctuary Phase 1, Direct seeding 2002 & 2003 Phase 1, Direct seeding 2002 & 2003 Large scale seeding of 25 – 35 mm hatchery produced stock, fall of 1 st growing season Provide broodstock for next breeding season Large scale seeding of 25 – 35 mm hatchery produced stock, fall of 1 st growing season Provide broodstock for next breeding season Capture of spat for subsequent re-stocking of other ponds using ‘spat bags’ Capture of spat for subsequent re-stocking of other ponds using ‘spat bags’ Dive surveys to monitor survival Dive surveys to monitor survival

North Cape Scallop Restoration Project Direct seeding of broodstock Release sites, based on habitat assessments

Scallop direct seeding 2002 Point Judith Pond680, Point Judith Pond680, Potter Pond286,300 Greenhill Pond188,980 Ninigret Pond581,090 Quonochontaug Pond 1,029, Potter Pond286,300 Greenhill Pond188,980 Ninigret Pond581,090 Quonochontaug Pond 1,029,840 Total 2,766,200 Total 2,766,200

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

Results, Abundance Ninigret Pond ~ 10,000 Quonochontaug Pond< 1,000 Green Hill Pond ~ 0 Potter Pond ~ 0 Pt. Judith Pond 0 North Cape Scallop Restoration Project Direct seeding of broodstock - release sites

Phase 2 – Spawner sanctuary from components Broodstock cages Maximize reproductive output by protecting broodstock Ninigret Pond 2004 to 2005, Quonochontaug Pond 2006 Hatchery produced broodstock 10,000 to 20,000 Broodstock cages Maximize reproductive output by protecting broodstock Ninigret Pond 2004 to 2005, Quonochontaug Pond 2006 Hatchery produced broodstock 10,000 to 20,000 Settlement of larvae monitored using ‘spat bag arrays’ 4 array locations per pond Six bags / line, Retrieved every 4 weeks, 2 week overlap Settlement of larvae monitored using ‘spat bag arrays’ 4 array locations per pond Six bags / line, Retrieved every 4 weeks, 2 week overlap Annual diver surveys to estimate abundance, (Survival of spat to maturity), Annual diver surveys to estimate abundance, (Survival of spat to maturity),

Spawner sanctuary Mature broodstock Maintained in cages for protection from predators

Spat Bag array Schematic Field example

Free Scallops Ninigret Pond 2004 to 2006 Spawner cages 10,000 broodstock 04 & 05 Spat bag arrays Same structure each year 4 sites, 6 bags, 8 collections Settlement index Σ mean spat per bag Dive surveys 2004, 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 Index , # Broodstock ~ 142, ,000 free (SE 55,000) 10,000 caged Settlement Index , # Broodstock ~ 210, ,000 free (SE 102,000) 0 caged Settlement Index 35 + ? ?

Summary – Ninigret Pond -04 and -05 results very encouraging -04 and -05 results very encouraging -06 results more difficult to interpret Broodstock only in western basin Settlement only in central basin (larval transport / asymmetric survival) -06 results more difficult to interpret Broodstock only in western basin Settlement only in central basin (larval transport / asymmetric survival) Environmental conditions extreme in 06 Wettest year on record Low salinity (16 to 27 ppt), stable stratification, evidence of anoxia Massive kill of scallops in central & northern basins Environmental conditions extreme in 06 Wettest year on record Low salinity (16 to 27 ppt), stable stratification, evidence of anoxia Massive kill of scallops in central & northern basins

Quonochontaug Pond Similar design to Ninigret Pond Spawner sanctuary Settlement surveys Monitoring broodstock abundance 2006, # Broodstock ~ 20,000 ~ 400 free 20,000 caged ?

Conclusions Due to high predation rates, direct seeding of scallops was not a productive restoration method Due to high predation rates, direct seeding of scallops was not a productive restoration method Caged spawner sanctuary with relatively few broodstock has been cost effective. Produced appreciable spatfalls and population increases Caged spawner sanctuary with relatively few broodstock has been cost effective. Produced appreciable spatfalls and population increases Water quality. High flushing rates may reduce likelihood of anoxic events Water quality. High flushing rates may reduce likelihood of anoxic events Benefit from a long term project commitment Benefit from a long term project commitment