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  • Underwater Videographic Survey of Submerged Aquatic Vegetation in Sequim Bay, WA

    August 2011

    by

    James G. Norris, Ian E. Fraser, and Hannah Julich

    Submitted To:

    Hansi Hals Environmental Planning Manager

    Jamestown S’Klallam Tribe 1033 Old Blyn Highway

    Sequim, WA 98382

    March 31, 2012

  • Marine Resources Consultants PO Box 816

    Port Townsend, WA 98368 (360) 385-4486

    jnorris@olympus.net ifraser@olympus.net

    Underwater Videographic Survey of Submerged Aquatic Vegetation in Sequim Bay, WA

    August 2011

    by

    James G. Norris, Ian E. Fraser, and Hannah Julich

    Submitted To:

    Hansi Hals Environmental Planning Manager

    Jamestown S’Klallam Tribe 1033 Old Blyn Highway

    Sequim, WA 98382

    March 31, 2012

    March 31, 2012 Date Signature (James G. Norris)

  • 2011 Sequim Bay Submerged Aquatic Vegetation Survey Final Report

    ii

    Table of Contents Table of Contents .................................................................................................................. ii List of Tables ........................................................................................................................ ii List of Figures ...................................................................................................................... iii Introduction............................................................................................................................1 Methods .................................................................................................................................2

    Overview ............................................................................................................................2 Study Sites ..........................................................................................................................3 Sampling Plan .....................................................................................................................5 Survey Equipment and Methods..........................................................................................5 Field Sampling Procedures..................................................................................................7 Tide Heights........................................................................................................................8 Underwater Video Data Post-Processing .............................................................................8 Parameter Estimation ........................................................................................................11 Personnel ..........................................................................................................................12

    Results..................................................................................................................................13 Eelgrass.............................................................................................................................13 Macroalgae .......................................................................................................................16 Other Observations............................................................................................................23

    Discussion ............................................................................................................................26 Methodology Evaluation ...................................................................................................26 Eelgrass.............................................................................................................................27 Macroalgae .......................................................................................................................30 Other Observations............................................................................................................31

    Recommendations ................................................................................................................32 Acknowledgments ................................................................................................................32 References............................................................................................................................33 Appendix A........................................................................................................................A-1

    List of Tables Table 1. Site and sample polygon areas for all sites and vegetation categories. ..................... 5 Table 2. Survey equipment used onboard the R/V Brendan D II during the 2011

    Sequim Bay submerged aquatic vegetation survey................................................. 6 Table 3. Sample processing notes from site sjs0995. ............................................................ 9 Table 4. Examples of common macroalgae species in the “Big Blades,”

    “Fuzzy/Bushy,” and “Ulvoids” categories seen on this survey. ............................ 10 Table 5. Notation and formulae for estimating vegetation fraction and areal extent at

    a single site. ........................................................................................................ 11 Table 6. Notation and formulae for estimating vegetation fraction within a given

    depth zone........................................................................................................... 12 Table 7. Summary statistics for eelgrass. ............................................................................ 13 Table 8. Summary statistics for Big Blades. ....................................................................... 17 Table 9. Summary statistics for Fuzzy/Bushy. .................................................................... 19 Table 10. Summary statistics for Ulvoids. ............................................................................ 21

  • 2011 Sequim Bay Submerged Aquatic Vegetation Survey Final Report

    iii

    Table 11. Animals observed during video post-processing. .................................................. 23 Table 12. Depths of sand dollar observations by site. ........................................................... 24

    List of Figures

    Figure 1. Illustration of eelgrass area coverage, eelgrass fraction, and patchiness................... 2 Figure 2. Illustration of mean minimum and maximum eelgrass depths. ................................ 2 Figure 3. Illustration of the line intercept sampling and estimation method. ........................... 3 Figure 4. Sequim Bay study sites. .......................................................................................... 4 Figure 5. The R/V Brendan D II............................................................................................. 6 Figure 6. Launching the camera towfish and “flying” the towfish during a transect. .............. 8 Figure 7. Underwater video transects (yellow) and eelgrass observations (red) during

    the August 2011 survey. ...................................................................................... 14 Figure 8. Eelgrass mean minimum (left) and maximum (right) depths (ft below

    MLLW)............................................................................................................... 15 Figure 9. North vs south eelgrass depth profile comparisons for the west and east

    shores.................................................................................................................. 15 Figure 10. Coefficient of variation as a function of estimated vegetation fractions for

    three macroalgae categories................................................................................. 16 Figure 11. Underwater video transects (yellow) and Big Blades observations (red)

    during the August 2011 survey. ........................................................................... 18 Figure 12. Underwater video transects (yellow) and Fuzzy/Bushy observations (red)

    during the August 2011 survey. ........................................................................... 20 Figure 13. Underwater video transects (yellow) and Ulvoids observations (red) during

    the August 2011 survey. ...................................................................................... 22 Figure 14. Sand dollar (Dendraster excentricus) observations (red)...................................... 24 Figure 15. Spot prawn observations (red) during the August 2011 Sequim Bay survey......... 25 Figure 16. Sample echograph from the BioSonics echosounder showing two large

    schools of fish. .................................................................................................... 25 Figure 17. Tracks for which we observed significant wood waste (cyan) and eelgrass

    observations (red)................................................................................................ 26 Figure 18. DNR ShoreZone data showing continuous (green), patchy (purple), and

    absent (black) eelgrass......................................................................................... 27 Figure 19. Eelgrass observations (red) from the 2000 and 2001 DNR SVMP survey

    and the 2011 survey (yellow transects). ............................................................... 28 Figure 20. Estimated mean minimum and maximum eelgrass depths (with confidence

    intervals) for flats47. ........................

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