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. 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
NC Scallops Landings ( )
recruitment failure following red tides in 87, several hurricanes in the 1990s and cownose ray predation.

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
Transplantation
High probability of survival relative to other types. I wouldn’t make this claim as I have no data to suggest that this is true. What if stocks are locally adapted and the transplantation takes place between locations that aren’t compatible? What if transplantation is stressful?
Easy to detect difference in abundance I’m not sure I understand this. Immediately following transplant there will indeed be more scallops, but is that restoration? Restoration is about rebuilding populations that persist and I don’t know that transplantation is any more easily assesed in the long term than any other strategy, unless the stocks are differentiated.
Lowers abundance at source population
Hatchery production
Fairly confident that organism will survive Again, I know of no data that supports this once the animals are in the field.
Expensive
Difficult to produce large enough animals
Larval releases
Allows for greater dispersal
Inexpensive
Efficient
Difficult to detect impact of release
In general, you are indicating that we know a lot more about these strategies then I am aware of. It is not necessary to talk about the advantages and disadvantages of each, particularly since we don’t know what works and no one strategy is likely to be “best” in all circumstances. You are presenting a study that looks at a strategy that might work and if it does it saves time and effort and money. I think it would be sufficient to mention the range of approaches, mention that the first two depend on the assumption that remnant populations are healthy enough to recover…something that in NC doesn’t seem to be happening (fishery has been closed in recent years, new water quality rules implemented but still no scallops). Consequently supplementation may be needed (although we don’t have recent recruitment data that necessarily indicates limitation) and that larval releases are a possible strategy.

4. 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
Log L (Pine Island source)
Log L (Anclote source)
Pine Island Sound Assignment Test
Read Arnold 2008 and modify accordingly
Read Liz’s thesis sections about assignment tests so that you understand how they work or go to
Retrospective genetic analysis by Liz.
Suggested several modifications
Multiple larval releases
allow for greater dispersal
Containment booms may not be required if released at proper time
Monitoring should adjust for greater larval dispersal
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 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 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
Broodstock
Location
Age at larval
release (days)
Number of
larvae
Total larvae
per site
Red
Taylor Bay 13
 24
250,000
Green 11
17 
1,000,000
Purple 14
12 
154,000
1,404,000
Orange
Piney Island 10
572,000
Yellow 9
15 
515,000
1,087,000
 Total 85
2,491,000 
Releases took place in September and October 2007

10. Background Methods Results Future Implications
June Scallops collected by snorkeling inside and outside of the deployment area
Muscle tissue was extracted for genetic analysis
Taylor Bay
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. Background Methods Results Conclusions
Genetic assessment to date
Mitochondrial DNA
In /57 (19.3%) wild scallops exhibited broodstock haplotypes
In /265 (24%) assessment scallops exhibited broodstock haplotypes
08-Assessment PI
08-Assessment TB
07-Broodstock PI
07-Broodstock TB
07- Wild Scallops
Mostly Haplotype 1
where overlap between broodstock and wild population greatest v

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

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
Assignment test shows limited separation, but as more microsatellites processed, increase statistical power, expect separation to become more distinct.

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
10 assigned to
broodstock released in
Assignment not strong

16. Background Methods Results 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
Assignment test shows limited separation, but as more microsatellites processed, increase statistical power, expect separation to become more distinct.