Oyster Restoration & Research in Virginia: Some Metrics & How We Monitor Them

Transcription

1 Oyster Restoration & Research in Virginia: Some Metrics & How We Monitor Them Oyster Restoration Workshop Myrtle Beach, SC May 20-21, 2004 P.G. Ross College of William and Mary VA Institute of Marine Science Eastern Shore Laboratory

2 Restoration Projects Now over 100 restoration sites in Virginia

3 Research Projects Project Construction Funded By Built By Research Funded By Adaptive Mgt. Fisherman s Island ( ) CBBT, VA Power, VMRC VMRC 1 EPA-CBP Yes, cultch Rappahannock River ( ) ACOE VMRC 1 NOAA Sea Grant Possibly, brood stock Oyster Heritage (2003-current) VA, ACOE Others VMRC 1 VEE, VORHF, NOAA Possibly, brood stock Army Corp. Project (2004- current) VA, ACOE Others VMRC 1 NOAA, ACOE Yes (proposed) 1 Built on sites chosen by and under the supervision of VMRC by commercial sub-contractors

4 Research Projects Project # Sites # Reefs Ht. Age (yrs) Scale Restoration Purpose Research Priorities FI ( 96-99) 1 13 Inter m 2 Mitigation Community structure, architecture Rapp. ( 01-02) OHP ( 03-04) ACOE ( 04-) reefs 6 4 Sub Sub m m 2 Habitat/Brood stock Habitat/Brood stock Scale (landscape & reef size), architecture Monitoring biological & physical parameters Opportunistically utilize existing or planned reefs for larger scale research

5 Great Wicomico River Salinity ~ 16 ppt Tide ~ 0.4 m Rappahannock River Salinity ~ 15 ppt Tide ~ 0.5 m Piankatank River Salinity ~ 16 ppt Tide ~ 0.4 m Now over 100 restoration sites in Virginia Fisherman s Island Salinity ~ 30 ppt Tide ~1 m

6 Reef Design Typical Marker Buoy Fisherman s Island Individual Shell Piles Rapp. WATER SURFACE (MLW) ~1-2 m Crest Base Flank REEF MOUND ~3 m SEABED

7 Monitoring Methods Oyster Settlement Measure timing & intensity of recruitment Crane's Creek Shell Bar 2003 # Oysters per m 2 per Week Ceramic 250 tiles, unglazed surface down 5 cm above reef surface 0 Bi-weekly 5/17 6/7until 6/28 settlement 7/19 8/9 8/30 begins, 9/20 10/11 then 11/1 11/22 weekly Date

8 # m -2 (solid line) Monitoring Methods Epifaunal Population Determine oyster population status ID species presence, richness, diversity Develop trophic models Mean Epifaunal Abundance & Diversity (+/- SE) 1000 Oyster density, size & biomass 800 Epifaunal diversity & trophic links 600 Oyster sex ratio Oyster 400 female fecundity Diver collected substrate sample x 25 cm to a depth of 10 cm 0.05 Intra-reef variation replication 0 Spring, Summer & Fall Disease prevalence & intensity 200 Genotyping (DEBY vs. local strains) 0 Summer 2001 Fall 2001 Summer H (dashed line)

9 # Oysters per sample # Oysters m -2 (+/- SE) Monitoring Methods Density, size & biomass Sex ratio Oyster Population (A) Drumming Ground May 2003 Female fecundity 20 Disease prevalence 0 & intensity Genotyping 60 Fall Summer Oyster Shell Ht. (1 mm intervals) CC SB BP PB DG PR Reefs within Rappahannock

10 Monitoring Methods % Mortality Day -1 (+ SE) Oyster Mortality & Growth Estimate predation mortality Indirectly measure food availability Evaluate size specific groups A Data Combined B B B Remote settlement onto clean oyster shell 0 Manipulate density MC DG PR TB Tether to frames Deploy Reef & recover Site (Rappahannock during various Project) seasons

11 Oyster Mortality (% day -1 ) % Xanthids Monitoring Methods Motile Resident Community Species presence, richness, diversity Develop trophic models Summer 2001 P= R 2 = Bury baskets of reef material into reef matrix Recover and capture organisms residing in baskets 6, 12 & 18 months post-deployment >40.5 Xanthid Abundance (# m 2 ) Carapace Width, 1 mm intervals Xanthid Size Frequency Distribution-Rapp. Project

12 Monitoring Methods Relative abundance of dominant species (Rapp ) Transient Community Species presence & abundance, richness, diversity (%) Develop trophic models Species (Resident and Transient Groups) Skilletfish (Gobiesox strumosus) Naked Goby (Gobiosoma bosci) Feather Blenny (Hypsoblennius hentzi) Menhaden (Brevoortia tyrranus) Croaker (Micropogonias undulatus) White Perch (Morone americanus) Striped Bass (Morone saxatilis) 55 Gill net 38 Trawl 4 Encircling 36 seine Observational 29 transects Underwater 18 video surveillance 8 Spot (Leiostomus xanthurus) 5

13 Monitoring Methods Physical Characteristics of Reef Determine static vs. dynamic nature of veneer Physical parameters to correlate with biological parameters 3-D shape & bathymetry Interstitial space Surface rugosity Particle geometry Large scale flow patterns Temporal changes..?

14 Monitoring Methods Physical Characteristics of Reef Side Scan Sonar Parrot s Rock Bathymetry 500 ADV Stacked Flow Profile DISTANCE NORTH (m) Scale 25 cm/s DISTANCE EAST (m)

15 Monitoring Methods Physical Characteristics of Reef Oyster Mortality-Interstitial Space % Oyster Mortality y = x R 2 = p = % Interstitial Space 140 mm 245 mm

16 Monitoring Methods Techniques Planned for 2004 Technique Oyster settlement (tiles) Quadrates (epifauna & physical) Plankton tows (larvae) Oyster fecundity Oyster disease & genotyping Frequency Bi-weekly/weekly (June-Oct.) Quarterly (spring, summer & fall) Bi-weekly (June-Sept.) Bi-weekly (May-Sept.) Semi-annually (July & Oct.) Utilizing correlation analysis and regression to determine relationships Current projects mainly focused on monitoring oyster population

17 Alternative Substrates Granite Limestone Marl Demolished Concrete Particle size, interstitial volume & surface rugosity Demolished Cinder Block Surf Clam Shell

18 Lessons Learned Location, location, location

19 Lessons Learned Location, location, location Architecture can matter

20 Lessons Learned Location, location, location Architecture can matter Reef matrix may be dynamic for sub tidal reefs

21 Lessons Learned Location, location, location Architecture can matter Reef matrix may be dynamic for sub tidal reefs Large scale H 2 O quality (anoxia) & weather (hurricane/rainfall) events can have impacts on success

22 Lessons Learned Location, location, location Architecture can matter Reef matrix may be dynamic for sub tidal reefs Large scale H 2 O quality (anoxia) & weather (hurricane/rainfall) events can have impacts on success Success criteria are likely variable regionally & locally minimal natural standards for comparison

23 Lessons Learned Location, location, location Architecture can matter Reef matrix may be dynamic for sub tidal reefs Large scale H 2 O quality (anoxia) & weather (hurricane/rainfall) events can have impacts on success Success criteria are likely variable regionally & locally minimal natural standards for comparison Measuring success at one point in time may be misleading-temporal trends may be more relevant

24 Lessons Learned Location, location, location Architecture can matter Reef matrix may be dynamic for sub tidal reefs Large scale H 2 O quality (anoxia) & weather (hurricane/rainfall) events can have impacts on success Success criteria are likely variable regionally & locally minimal natural standards for comparison Measuring success at one point in time may be misleading-temporal trends may be more relevant When and how we sample really matters

25 Some Criteria for Success Oyster population growth +, or at higher densities, at least stable over several years Multiple oyster size/age cohorts present over time Overall community diversity increasing over time to stabilize after 3-5 years Key community species (i.e. trophically) present in multiple age classes. Identify species/genera in multiple taxa that are indicative of healthy community Does community equilibrate quickly (e.g. 2-3 years) after significant environmental perturbations Measurement of these variables requires multiple years of monitoring (possibly 5+ years continuously). The challenge is to get financial commitments to longer-term monitoring than is currently standard

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28 Potential Hurricane Impacts?? A) Reefs with stable oyster abundance Hurricane Isabell # Oysters m SPRING 2003 SUMMER 2003 FALL 2003 SB BP DG B) Reefs with lower oyster abundance Hurricane Isabell SPRING 2003 SUMMER 2003 FALL 2003 CC PB PR

29 Flux Measurements Bi-monthly Apr Oct: DIN (NH 4+, NO - 2 NO 3- ), DO DIP (PO 3-4 ) DON Chl a substrate collar

30 160 Cages Deployed June 2003 Palace Bar Reef Cages Reef Schematic