An assessment of intertidal biota subject to wave impacts from Pacificat Ferries

by Dr. Bill Austin, Khoyatan Marine Laboratory, February 2000


Protocol for intertidal biota assessment


ROCKY SHORE QUADRAT STUDIES: Methods (Khoyatan)

  1. SELECTING STATION AND TRANSECT LOCATIONS
  2. MINIMIZING IMPACTS
  3. ESTABLISHING STATION LOCATION [for each transect]
  4. Personnel: 3--coordinator and 2 leaders; Equipment: nautical chart, dividers
    1. Record station number--a unique number for each general site + year [e.g., 4/96]
    2. Record transect letter--A if on left and B if on right when facing landward]
    3. Record date, start time, coordinator & transect leader [add team names later]
    4. Record name of locality per hydrographic char
    5. Determine latitude and longitude based on chart to nearest 0.01 minute [18 meters] at high water mark. &/or based on handheld GPS if available
    6. Record degree of wave exposure [protected: less than 1km fetch; exposed: open outer coast]
    7. Record fresh water, tide currents [observed or from chart] and weather
    8. Draw land/seascape showing key reference points for transect on BACK of station sheet

  5. ESTABLISHING A NEW TRANSECT LINE [for a new rather than revisited site]
  6. A. Establishing quadrat heights at 1.0, 1.5, 2.0, 2.5, 3.0, 3.5 m intervals above 0 tide level [intervals might be adjusted for local areas with larger or smaller tide range]
    Personnel: 2-- 2 survey rod holders
    Equipment: 2 rods, sight level, data forms, tide tables, calculator, flagging tape with weight
    1. Lay out line from above high tide mark to waters edge and perpendicular to the shore [keep to left of line; allow extra line at lower end to extend line as the tide falls]
    2. In front of current year's tide table guide find secondary port closest to station location.
    3. Note time and height corrections IN FEET for LARGE low tide and LARGE high tide
    4. Calculate predicted tide height at time of survey per station work sheet [This requires use of Table 6 and 6A in the front of the tide tables]
    5. Determine the difference between the present predicted tide height and the next higher quadrat [e.g., if present predicted water height is 1.3m, then next higher quadrat is 1.5 = 0.2m higher]
    6. Hold one survey rod at the waters edge; count DOWN the no. of decimeter marks from the top of the SECOND survey rod until = the difference calculated in 5 [e.g. 0.2m or 2dm]
    7. Move second rod upshore until you estimate that you are at the next quadrat location
    8. Hold site level next to the decimeter mark established in 6 [e.g. 2dm]
    9. Sight through the level and rotate up or down until the bubble is CENTRED on horizontal line in the level
    10. Note position of this line on the FIRST rod. If it is below the top of the rod you need to move up; if it is above the rod, you need to move down-- until just at top of rod [NOTE: where the horizon line or shoreline is more than 1/2 mile away use THIS rather than the site level as line to locate just at the top of the first rod. This is easier and more accurate than the site level]
    11. Place weighted flagging tape at this point at base of 2nd rod
    12. Bring first rod up place at point on transect where second rod located
    13. Count down 0.5m or 5dm on second rod; move up beach until estimate that you are 0.5 above the first rod
    14. Repeat sighting adjustments [as in 8-10] until at correct height
    15. Place second weight at base of second rod
    16. Repeat until up to 3.5m [or whatever interval you have chosen]
    17. You may need to complete establishment of lower quadrat point when tide as lowered to below 1.0 meters

    B. Establishing position of the 3.5m quadrat site relative to landmarks
    Personnel: 4: persons: 3 tape holders incl. reader, recorder/photographer
    Equipment: 2 100 m tapes, sighting compass, camera, flagging tape, 3x5 cards, felt pen
    1. Make up 3x5 card: for station no.& transect letter e.g., 4A/96 take close-up photo of this card [2-3ft.]; check off on sta. sheet
    2. select two moderately separated shore points which are likely to be permanent. Ideally they should each be at about a 45 degree angle to the transect line.
    3. One person hold the reels of the two 100 m tapes reels at the 3.5m mark while the other two each pull a tape to the selected landmarks [these 2 persons should carry a compass and flagging tape with them].
    4. On the Transect form note:
      • distance from BOTH the left and right landmarks to the 3.5m quadrat point
      • Compass bearings [uncorrected for declination] FROM the left and right landmarks TO the 3.5m quadrat point.
    5. Hold flagging tape at each landmark while person 4 takes photos 2 to 5.
    6. Temporarily leave tapes in place for establishing transect [below]

    C. Establishing position of transect

    Personnel: 4 persons: 2 tape holders, reader, recorder/photographer
    Equipment: 2 100 m tapes, 1 50 m tape, sighting compass, camera, flagging tape

    1. Extend 50 m tape from 3.5 m marker seaward along the transect line be sure 0 point on metric side of tape is at the 3.5m point
    2. One person hold the reels of the two 100m tapes at some point along the transect between the 2.0 and 2.5 m levels [referred to below as the “halfway” point]
    3. On the Transect form note:
        location of the halfway point in meters ALONG the transect line
      • distance from the left and right landmarks to the halfway point
      • compass bearing FROM left and right landmarks to the halfway point
      • compass bearing DOWN transect toward sea
    4. Also on the transect form note the location of the flagging tape weights from the 3.5m level [0.0meters] down to the 1.0m level [the lower most determinations may have to be deferred until the tide is below the 1.0m level.
    5. Take photos 6 - 11 per station sheet
    6. Reel up the 100 m tapes.

    D. Determining slope of transect
    1. Lay survey rod along slope between the 3.0 and 3.5m levels along transect
    2. Place the angle finder on top of the rod
    3. Read slope angle in degrees and record on transect sheet
    4. Repeat steps 1-3 for slope between 1.5 and 2.0m levels along transect [an angle reading on a protractor held on top of a level may be estimated if an angle finder is not available]

    E. Placing primary & secondary quadrats [team divided into 2 pairs]
    Personnel: 2 persons Equipment: quadrat frame, dowels, 1/4" polypropylene rope ring
    1. These will be placed AS data are collected
    2. Put in dowel legs on quadrat frame
    3. For Primary quadrats place each frame with LOWER LEFT OUTSIDE corner [facing] landward] on flagging tape at 3.5 and 3.0 meters with left side parallel to 30 m tape [hang plumb bob from outer corner to the flagging tape weight for accuracy]
    4. For Secondary quadrats place rope ring in approximate square at same level as quadrat frame and 2-3 meters to left of transect facing landward.
    5. AFTER completing photos and counts place NEXT pair of frames at 1.5 and 1.0 meters [during period of lowest tide]
    6. Finish up with frames at 2.5 and 2.0 meters.

  7. RE-ESTABLISHING TRANSECT LINES FROM PREVIOUS STATION
  8. Personnel: 4 people; Equipment: compasses, 2 100m tapes, flagging weights, station transect information,and photos from previous station; new data sheets.

    A. Locating the station
    1. Bring to the field the photos and station data sheets from previous survey
    2. Check for congruency: latitude and longitude, any general compass bearings, photographs, landscape drawing on the back of the station sheet

    B. Locating 3.5m mark for each transect
    1. From photographs from the previous year, locate the right and left landmarks
    2. From each landmark extend 100m measuring tape to distance specified on previous station transect sheet to the 3.5m mark.
    3. Move the tapes until the distance specified for each landmark intersect. Mark this point with a weighted flagging tape as the 3.5m mark.
    4. Take compass readings [uncorrected for declination] FROM each landmark to the 3.5m mark and compare with those at previous station.
    5. If they do not agree, place a quadrat frame with lower left hand corner at 3.5m marks determined from each method and compare with photo of 3.5m quadrat from previous station.
    6. Note any disparities. Tape measurements are, typically, less subject to error.

    C. Positioning the transect line [a fifth person would be useful here]
    1. From each landmark extend 100m measuring tape to distance specified on previous station transect sheet to the "halfway" point [3 persons]
    2. Move the tapes until the distance specified for each landmark intersect. Marke this point with a weighted flagging tape as the “halfway” mark.
    3. Extend 50m tape from the 3.5m to the weighted flagging tape. Note if distance corresponds with that measured for previous station.
    4. Compare with compass bearings as in B above

    D. Positioning quadrats
    1. Extend 30m tape down beach in line with 2 points defined in B and C above
    2. Place weighted flagging tape at points noted for 3.5 to 1.0m from previous station.

    E. Determining slope [as under IV.D]

    F. Placing primary and secondary quadrats
    1. Primary as under IV.D
    2. PLUS compare vertical view with that in photo from previous station
    3. Note any visual disparities
    4. Secondary: recommend that try to place in different position from previous year as movement of rocks can impact on sessile biota.
    5. It might also be interesting to note any differences under the SAME rocks from previous station.

  9. INDIVIDUAL PRIMARY QUADRAT ANALYSIS [ON TOP OF ROCK SURVEY]
  10. Personnel: 2 persons: data collector and recorder, + camera person as needed
    Equipment: 3x5 cards, felt pen, sampling equipment

    A. Quadrat photo
    1. Make 3x5 card for appropriate levels: e.g., 3.5 meters & 3.0 meters
    2. Weight down if necessary with clip
    3. ADD 3x5 card: for station no.& transect letter. e.g., 4A/96
    4. Place along edge of quadrat frame adjacent to transect line
    5. Ask camera person to take photo--facing quadrat FROM transect line and directly over centre of quadrat

    B. Level of identification

    C. Calculation of cover: for aggregated species and/or those which cover a large area
    1. Lower the plumb bob at each point where two strings cross [intersect] [total of 36 intersects] Do NOT include where strings attach to frame
    2. Identify what the plumb bob contacts INCLUDING bare rock or other substrate
    3. Make a tick next to the appropriate species in the column labeled “no. interects”
    4. IF one species overlies another, such as rock weed over a mussel make a tick next to BOTH species [do not make a mark for both bare rock and overlying species]
    5. Complete for each of the 36 intersects
    6. % cover can be calculated later by totaling the tick marks for each species and dividing this total by 0.36] [NOTE the total for all may be greater than 100%]

    D. Estimate of abundance: for less common species
    1. Abundance will only be estimated as: 1, 2, few [3-10], common [more than 10]
    2. Note approximate area covered by quadrat frame, then lift off frame
    3. Carefully go over quadrat area, moving aside seaweeds as necessary but NOT turning over rocks note estimates of abundance for each species found
    4. Then go through list on primary form to see if have missed any species and to note as nil or 0 where you feel reasonably assured that the species are not present in the quadrat area.

  11. INDIVIDUAL SECONDARY QUADRAT ANALYSIS [under rock survey]
  12. Personnel: 2 persons: data collector and recorder, + camera person as needed
    Equipment: 3x 5 cards, felt pen, sampling equipment

    A. Substrate:
    1. Note the typical range in size of boulders and cobbles

    B. Quadrat photo
    1. Make 3x5 card for appropriate levels: e.g., 3.5 meters and 3.0 meters
    2. Weight down if necessary with clip
    3. ADD 3x5 card: for station no. and transect letter. e.g., 4A/96
    4. Place along edge of quadrat rope
    5. Ask camera person to take photo directly over centre of quadrat

    C. Level of identification: Same as for Primary Quadrat

    D. Search pattern and abundance estimates

    1. Turn over up to 6 of the larger boulders/cobbles (one at a time)
    2. Record size of each in centimeters based on average diameter
    3. Observe animals on both the under side of rock and on the surface below rock. Do NOT dig into soft substrate below rock
    4. Categorize abundance under each rock as 1; 2; few [3-10]; common [more than 10]
    5. CAREFULLY return each rock to its original position
    6. Note some boulders may have been previously turned.

    Page last updated 00-03-10