Collaborative Shellfish Modeling in Delaware Bay Fosters Better Shellfishery Management. D. Munroe, J. Klinck, E. Hofmann, E. Powell.

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1 Collaborative Shellfish Modeling in Delaware Bay Fosters Better Shellfishery Management D. Munroe, J. Klinck, E. Hofmann, E. Powell. Delaware Estuary Science Summit, Cape May NJ, Jan

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4 æ æ Age - AveAgeMort ö ö P mort = 0.5ç 1+ tanhç è è AveSpreadMort ø ø DyPoGEn Spatially-Explicit Individual-Based Numerical Model Multiple Linked Population Dynamics Models ( ) LarvSurv = R P =1- LarvSurv K noff nparents æ æ Age - AveAgeMort ö ö P mort = 0.5ç 1+ tanhç è è AveSpreadMort ø ø be ( g Age ) Ff = ae Df = dff dage = abge ç g Age è æ ( )+ æ ç be ( g Age ) ö ö è ø ø W = W 1 - e -k(age-age ) ( ) b ( ) b MaxOff noff = W W e -k ( Age-Age 0 ) FrParents = FracParents 10 ( N FracParentsVar ) nparents = max( 0.5 FrParents LastAnimal, minparent)

5 The Model Individual Genetics: Based on parental genotype Offspring created by meiosis DyPoGEn Dynamic Population Genetics Engine

6 The Model Individual Genetics: GENETICS Based on parental genotype Offspring created by meiosis DyPoGEn Dynamic Population Genetics Engine Larvae can: Experience mortality Remain within source population Disperse Informed by coupled particle model (larval growth-behaviour & ROMS*) *Narváez, D.A. et al. In Press Journal of Marine Research

7 The Model Individual Genetics: GENETICS Based on parental genotype Offspring created by meiosis DyPoGEn Dynamic Population Genetics Engine Recruits will: Grow Experience mortality or fishing Change sex Spawn Larvae can: Experience mortality LARVAL DISPERSAL Remain within source population Disperse Informed by coupled particle model (larval growth-behaviour & ROMS)

8 The Model Individual Genetics: GENETICS Based on parental genotype Offspring created by meiosis DyPoGEn Dynamic Population Genetics Engine Recruits will: Grow SPATIALLY EXPLICIT Experience mortality or fishing Change sex Spawn Larvae can: Experience mortality LARVAL DISPERSAL Remain within source population Disperse Informed by coupled particle model (larval growth-behaviour & ROMS)

9 The System Delaware Delaware Bay New Jersey Delaware Estuary Oyster Fishery Eastern Oyster (Crassostrea virginica) Stock Assessment oyster timeseries 1953-current

10 Strong salinity gradient. Oyster populations respond biologically. From: Hofmann et al., Oceanography, 22:

11 Strong salinity gradient. Oyster populations respond biologically LOW Growth Mortality Recruitment HIGH From: Hofmann et al., Oceanography, 22:

12 Locations Represented by Simulated Populations Model Output

13 BB AA Locus AA AA Delaware Bay Neutral Marker Alleles Used to track genetic connectivity over time

14 Is larval dispersal or post-settlement processes more important to genetic connectivity? Genetic connectivity is influenced by: Relative mortality Relative abundance Munroe, D., J. Klinck, E. Hofmann, and E.N.P Powell The role of larval dispersal in metapopulation gene flow: local population dynamics matter. J. Mar. Res. 70:

15 How do fisheries influence genetic connectivity? Questions What role do MPAs play in genetic connectivity?

16 How do fisheries influence genetic connectivity?

17 How do fisheries influence genetic connectivity?

18 How do fisheries influence genetic connectivity?

19 Seed And Sack Fishery Seed fishery - no lower size limit Sack fishery - lower size limit 63.5 mm (2.5 inch) Photo Credit: Louisiana Department of Wildlife & Fisheries

20 How do fisheries influence genetic connectivity? NonSelective Fishery Lower Size Limit Fishery (Seed) (Sack) Paired T-test NonSelective < Size Selective Fishery allele change versus Base Case on average 3.5 % lower allele frequency P T df 18

21 Shifts in source:sink dynamics What role do MPAs play in genetic connectivity?

22 MPAs: Increasing export of allele with surrounding fishing pressure What role do MPAs play in genetic connectivity?

23 MPAs: Can alter source:sink locations What role do MPAs play in genetic connectivity?

24 Allele Export Allele Export Allele Export Summary Fishing: Increasing fishing decreases allele export True for both fishery types Fishing Pressure For a given regime/area, and keeping fishing rate constant, non-selective fisheries lead to a greater decrease in allele export On average, 3.5% lower MPAs: MPAs can enhance protected area genotypes Especially with high surrounding fishing pressure Fishing Pressure Fishing Pressure

25 Allele Export Allele Export Allele Export Summary Fishing: Increasing fishing decreases allele export True for both fishery types Fishing Pressure For a given regime/area, and keeping fishing rate constant, non-selective fisheries lead to a greater decrease in allele export On average, 3.5% lower MPAs: MPAs can enhance protected area genotypes Especially with high surrounding fishing pressure Fishing Pressure Fishing Pressure

26 Allele Export Allele Export Allele Export Summary Fishing: Increasing fishing decreases allele export True for both fishery types Fishing Pressure For a given regime/area, and keeping fishing rate constant, non-selective fisheries lead to a greater decrease in allele export On average, 3.5% lower MPAs: MPAs can enhance protected area genotypes Especially with high surrounding fishing pressure Fishing Pressure Fishing Pressure

27 we got a year's worth of precipitation in those two months. Some streams saw peak levels that were 300% higher than high-water records Joshua Galster, Montclair State University The flood was so massive it pushed all the salt water out into the ocean Douglas A. Burns, U.S. Geological Survey

28 Low Salinity Anomaly 2011 High snow melt in spring Hurricane Irene Tropical Storm Lee Average Salinity Over Oyster Beds From: D. Bushek - Annual Dermo Monitoring Program

29 Impacts on Oysters Upbay mortalities extremely high 60%* Mortality biased to large animals Mortality of market-size oysters ~ 76%* How will these changes impact oysters? How long will these effects last? *Powell EN, et al Report of the 2012 Stock Assessment Workshop (14th SAW) for the New Jersey Delaware Bay oyster beds. Port Norris, NJ: Haskin Shellfish Research Laboratory Report.

30 Upbay? Downbay

31 Upbay Downbay

32 Upbay 10 Years Downbay

33 Frequency Population 1 - Post-Flood Simulated Length Frequencies Simulation Year < >150 Length Class (mm)

34 Frequency Population 1 - Post-Flood Simulated Length Frequencies Simulation Year < >150 Length Class (mm)

35 Frequency Population 1 - Post-Flood Simulated Length Frequencies Simulation Year < >150 Length Class (mm)

36 Post-Flood - What we might expect: Reduced length frequencies & abundance upbay ~10 years No change to gene flow (neutral alleles only) Economic Projections*: Estimated $5.3 million direct loss to fishermen *These projections do not account for loss of production downbay deriving from transplanted oysters

37 Thanks to Stock Assessment Team: Haskin Shellfish Research Lab, NJDEP, Oystermen of Delaware Bay CoAuthors: Eileen Hofmann John Klinck Eric Powell Funding for this research provided by NSF Grant # OCE OCE Dmunroe@hsrl.rutgers.edu

38 Length Class (mm)

39 Simulation Stock Assessment Length Class (mm) Length Class (mm)

40 Is larval dispersal or post-settlement processes more important to genetic connectivity? How do fisheries influence genetic connectivity? What role do MPAs play in genetic connectivity?

41 Is larval dispersal or post-settlement processes more important to genetic connectivity? Genetic connectivity is influenced by: Relative mortality Relative abundance *Munroe, D., et al The role of larval dispersal in metapopulation gene flow: local population dynamics matter. Journal of Marine Research. 70:

42 Allele Export Allele Export How do fisheries influence genetic connectivity? Increasing fishing decreases allele export True for both fishery types Fishing Pressure Non-selective fisheries lead to a greater decrease in allele export On average, 3.5% lower Fishing Pressure

43 Allele Export What role do MPAs play in genetic connectivity? MPAs can enhance protected genotypes Especially with high surrounding fishing Fishing Pressure