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International Conference on Shellfish Restoration 2006 - Charleston, SC Oyster Reef Restoration Using “Spat Seeding”: Early Reef Development and Performance at Sites in New Hampshire, USA http://oyster.unh.edu Ray Grizzle, Jennifer Greene, and Mark Capone
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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
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A ‘pristine’ NH oyster reef few dead shells many live oysters (500/m 2 in some areas) extensive vertical structure in some areas
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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
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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
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Life Cycle of the Eastern Oyster, Crassostrea virginica Trochophore Larva Veliger Larva Straight-hinge stage Juvenile/Spat Adult Egg Oyster Life Cycle Sessile, Benthic
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Oyster Restoration = Facilitating the Life Cycle Remote Setting, Early Grow-out (Nursery), & Reef Construction
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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
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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
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Adams Point-Experimental Design
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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!
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Nursery Raft Survival and Growth ~75% survival is typical for 6 – 8 weeks on nursery raft Growth typically averages 2 - 3 mm/week Some animals ~1 mm/day
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Development of Constructed Mini-Reefs Adams Point, 2003-2006 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…
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Performance of Constructed Mini-Reefs Adams Point, Summer 2006 Maximum ~6% water filtration (seston removal) after 3.2 years
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Two New Programs: Oyster Conservationists and Shell Recycling Do you want to participate in oyster restoration in New Hampshire? http://oyster.unh.edu
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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
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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
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