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A genetic assessment of Bay Scallop restoration in Bogue Sound, North Carolina

A genetic assessment of Bay Scallop restoration in Bogue Sound, North Carolina. Sherman, M. 1 , D. Schmidt 2 , A.E. Wilbur 1 1 Department of Biology and Marine Biology, Center for Marine Science, University of North Carolina Wilmington, Wilmington, NC 28409

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A genetic assessment of Bay Scallop restoration in Bogue Sound, North Carolina

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  1. A genetic assessment of Bay Scallop restoration in Bogue Sound, North Carolina Sherman, M.1, D. Schmidt2, A.E. Wilbur1 1Department of Biology and Marine Biology, Center for Marine Science, University of North Carolina Wilmington, Wilmington, NC 28409 2 Goose Creek Rd. Newport, NC 28570 

  2. NC Scallops Landings (1950-2005) Background Methods Results Conclusions State of the scallop fishery in North Carolina • Declining fishery likely due to several factors • Red tide in 1987 • Recruitment failure • Predation • Cownose rays • Hurricanes • low scallop abundance has prompted the investigation of restoration practices

  3. Background Methods Results Conclusions Types of restoration strategies • Preserve and protect • Releases population from pressures • Rebuild habitat • Useful for substrate limited organisms • Supplementation • Transplantation • Hatchery production • Traditional hatchery practices • Spawn, grow to size, and release • Larval releases • May be inexpensive and efficient

  4. Pine Island Sound Assignment Test Log L (Pine Island source) Log L (Anclote source) Background Methods Results Conclusions Larval releases in Florida- Pine Island Sound (Arnold 2008) • In 2003, 1,500,000 larvae released from hatchery stock from 12 Anclote broodstock scallops • In 2005, found an increase in abundance by a factor of 18 • indicative of enhancement • Retrospective genetic analysis • Microsatellite analysis (9 loci) (Hemond 2006) • Genotypes of broodstock not determined • Broodstock source population (Anclote, FL) • Pine Island scallops from before (2001) and after (2005) the 2003 larval release • Could not confidently assign a source population • Lack of differentiation between sources limits assignment success Jay Leverone releasing larvae in Pine Island Sound Frequentist method (Praetkau et al. 1995) Based on probabilistic framework

  5. Background Methods Results Conclusions Broodstock scallops are spawned Larvae are grown to the pediveliger stage Genetic signatures of broodstock and assessment scallops are compared to identify potential hatchery offspring Larvae are released into the wild Broodstock scallops are genetically characterized Spat and adult assessment scallops collected and genetically characterized

  6. Background Methods Results Conclusions Fall 2007- A total of 85 wild scallops were collected for broodstock - Separated into five sets of broodstock

  7. Background Methods Results Future Implications Before release spat traps were deployed surrounding the release site • 6 traps placed 30-50 feet from release site to be collected one month after deployment

  8. Background Methods Results Conclusions • Scallops were then introduced to the release site • Healthy subtidal seagrass bed • Low tide • Limit vertical profile

  9. Background Methods Results Conclusions Larval Release Summary Releases took place in September and October 2007

  10. Background Methods Results Future Implications June 2008- Scallops collected by snorkeling inside and outside of the deployment area • Muscle tissue was extracted for genetic analysis TaylorBay Piney Island

  11. Background Methods Results Conclusions • Genetic assessment to date: Mitochondrial DNA • Sequencing of a 930bp region- 113/142 showed unique haplotypes • 07 Wild scallops (N=57) 48 haplotypes (46 uniques) • 07 Broodstock TB (N=53) 44 haplotypes (43 uniques) • 07 Broodstock PI (N=32) 26 haplotypes (24 uniques) Overlap between broodstock and wild population before releases v v v

  12. 08-Assessment PI 08-Assessment TB 07-Broodstock PI 07-Broodstock TB 07- Wild Scallops Background Methods Results Conclusions Genetic assessment to date • Mitochondrial DNA • In 2007- 11/57 (19.3%) wild scallops exhibited broodstock haplotypes • In 2008- 69/265 (24%) assessment scallops exhibited broodstock haplotypes Mostly Haplotype 1 where overlap between broodstock and wild population greatest v

  13. Background Methods Results Conclusions AI115 Microsatellite Analysis • 5 loci to date • Allele frequency plots suggest wild population and broodstock not differentiated AI131 AI327 g340 m26 07- Taylor Bay 07-Piney Island 07- Wild Scallops

  14. Background Methods Results Conclusions Assignment test of potential source populations • 25/57 wild correctly assigned to wild • 18/85 broodstock scallops correctly assigned to hatchery • Less than ½ of broodstock and wild scallops assigned correctly

  15. Background Methods Results Conclusions Assignment of assessment scallops • Taylor Bay • 41 mtDNA matches • 22 assigned to broodstock released at Taylor Bay • 2 assigned to broodstock released at Piney Island • 17 assigned to wild population • Piney Island • 14 mtDNA matches • 4 assigned to broodstock released at Piney Island • 10 assigned to broodstock released in Taylor Bay

  16. Background Methods Results Conclusions • Conclusions • Potential enhancement looks promising, but significant impact not detected with microsatellites to date • 22/157 (~14%) properly assigned scallops in Taylor Bay • 4/108 (~4%) properly assigned scallops in Piney Island • Increased loci will likely increase the power to detect hatchery scallops • Suggestions for future assessments • Broader perspective • Larval transport away from release site • Broader geographic sampling • Density survey • Larval releases may work- how well? • Are there more scallops?

  17. Acknowledgements • NC Sea Grant Fisheries Resource Grant 06-EP-07 • UNCW DNA Analysis Core Facility • Bill Arnold (FFWRI), Skip Kemp (CCC), Tina Moore (NCDMF), Don Morlock

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