International Conference on Shellfish Restoration Charleston, SC Oyster Reef Restoration Using “Spat Seeding”: Early Reef Development and Performance at Sites in New Hampshire, USA Ray Grizzle, Jennifer Greene, and Mark Capone

Current Status of the Eastern Oyster, Crassostrea virginica (P. Trowbridge) Extreme population declines in many areas from disease (MSX, Dermo), predators, over-harvesting, pollution, habitat degradation New Hampshire Estuaries Project goals: 20 restored acres, and 50,000 bushels standing stock by 2010 Nova Scotia Maine Cape Cod Great Bay

A ‘pristine’ NH oyster reef few dead shells many live oysters (500/m 2 in some areas) extensive vertical structure in some areas

Badly Degraded Reef Reef With Some ‘Structure’ mostly dead shells sparse live oysters (~20/m 2 ) minimal vertical structure few dead shells many live oysters (~100/m 2 ) some vertical structure excessive sedimentation

How do we restore oyster reefs? 1.Identify potential causes for population declines on site-by-site basis 2.Design site-specific construction/restoration protocol 3.Assess initial construction/restoration 4.Maintain “restored” area 5. Assess long-term development and performance

Life Cycle of the Eastern Oyster, Crassostrea virginica Trochophore Larva Veliger Larva Straight-hinge stage Juvenile/Spat Adult Egg Oyster Life Cycle Sessile, Benthic

Oyster Restoration = Facilitating the Life Cycle Remote Setting, Early Grow-out (Nursery), & Reef Construction

Shellfish Restoration Sites, Dates of Construction: Salmon Falls River, 2000 South Mill Pond, 2001 Adams Point, 2003 Nannie Island, 2004 Bellamy River, 2005, 2006 Salmon Falls River Bellamy River Adams Point Nannie Island South Mill Pond

Adams Point – An Experimental Scale Restoration Project Experimental design (2 x 2 factorial) to test: 1) two cultch types, and 2) two spat seeding densities Each treatment replicated 3 times 12 mini- reefs (2m x 3m) constructed Mini-reef bases built up to ~30 cm height with crushed granite Spat-on-cultch (shell or rock) spread over surface of granite bases

Adams Point-Experimental Design

How many spat should be expected from the remote setting process? Spat setting success has ranged from 50% in our trials Important factors:  cultch  food  water quality  condition of the larvae We can’t believe they all died!

Nursery Raft Survival and Growth ~75% survival is typical for 6 – 8 weeks on nursery raft Growth typically averages mm/week Some animals ~1 mm/day

Development of Constructed Mini-Reefs Adams Point, Consistent density decline Similar (but elevated compared to natural reef) densities after ~3 years post-construction Some originally seeded oysters in 2 nd year of maturity Substantial development of vertical structure…

Performance of Constructed Mini-Reefs Adams Point, Summer 2006 Maximum ~6% water filtration (seston removal) after 3.2 years

Two New Programs: Oyster Conservationists and Shell Recycling Do you want to participate in oyster restoration in New Hampshire?

Acres Site/Construction Year(s) Larvae Source/Experimental Test RestoredCurrent Status Salmon Falls River/2000XBreed larvae vs. native transplant0.1~100% mortality South Mill Pond/2001ME larvae; oysters with blue mussels<0.1~100% mortality Adams Point/2003ME larvae; low vs. high density0.05>50% mortality Nannie Island/2004ME larvae; large vs. small reefs1.25>50% mortality Bellamy River/2005NH larvae; multiple mini-reefs1.5 >50% mortality 2006NH larvae; multiple mini-reefs1.5? TOTAL: 4.4 acres Summary of New Hampshire Shellfish Restoration Projects

ACKNOWLEDGMENTS UNH: Ryan McDonnell, Kaitlin Graiff, Dave Shay, Deb Lamson, Ben Winslow, Sarah Mikulak, Michelle GraffamUNH: Ryan McDonnell, Kaitlin Graiff, Dave Shay, Deb Lamson, Ben Winslow, Sarah Mikulak, Michelle Graffam Interns: William Walker, Winnie Wong, Sarah Morrison, Alicia June, Blake BowickInterns: William Walker, Winnie Wong, Sarah Morrison, Alicia June, Blake Bowick Oyster Conservationist Volunteers, Active Shell RecyclersOyster Conservationist Volunteers, Active Shell Recyclers Toni Simmons/Muscongus Bay AquacultureToni Simmons/Muscongus Bay Aquaculture Davis FoundationDavis Foundation