CRED Towed-Diver Benthic Characterization Survey at Rose, American Samoa in 2012

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What does this data set describe?

Title:
CRED Towed-Diver Benthic Characterization Survey at Rose, American Samoa in 2012
Abstract:
To support NOAA Coral Reef Conservation Program (CRCP) long-term goals for sustainable management and conservation of coral reef ecosystems, towed-diver surveys (aka. towboard surveys) were conducted by the Coral Reef Ecosystem Division (CRED) of the NOAA Pacific Islands Fisheries Science Center (PIFSC) as part of the Pacific Reef Assessment and Monitoring Program (RAMP) Cruises. 9 towboard surveys (19.51 km in length), were conducted at Rose during the American Samoa RAMP Cruise HA1201 from 20120401 to 20120426. Towboard surveys are a good method for obtaining a general description of large reef areas, assessing the status of low-density populations of large-bodied reef fish, large-scale disturbances (e.g., bleaching), general distribution and abundance patterns of macro-invertebrates (e.g., Crown of Thorns sea stars, giant clams), and for assessing trends in these populations and metrics. A pair of scuba divers (1 fish and 1 benthic diver) are towed 60 m behind a small survey launch at a speed of 1-2 knots and a depth of approximately 15 m. Each survey is 50 min long, covers about 2 km of habitat, and is divided into ten 5-minute survey segments. The fish diver records, to the lowest possible taxon, all large-bodied reef fishes (greater than 50 cm total length) seen within 5 m either side and 10 m in front of the towboard. Length of each individual is estimated to the nearest cm. The fish towboard is also outfitted with a forward-facing digital video camera to record the survey swath. The benthic diver records percent cover of coral and macroalgae, estimates benthic habitat type and complexity, and censuses a suite of benthic macroinvertebrates including Crown of Thorns sea stars and sea urchins. The benthic towboard is equipped with a downward-facing digital still camera which images the benthos at 15-second intervals. These images are analyzed for percent cover of coral, algae, and other benthic components. Both towboards are equipped with SEABIRD SBE-39 temperature/depth sensors set to record at 5-second intervals. Latitude and longitude of each survey track is recorded at 5-second intervals using a Global Positioning System (GPS) receiver onboard the tow boat. A layback algorithm is applied to more accurately map the position of the divers with respect to the reef environment. This algorithm calculates the position of the divers based on the position of the tow boat taking into account the length of the tow rope, the depth of the divers, and the curvature of the survey track. This metadata applies to the benthic characterization observations.
Supplemental_Information:
The benthic characterization observation data includes benthic composition, complexity estimations, observed macro-invertebrates, and observed man-made objects. Classification of habitat complexity was recorded in six categories: low (L), medium-low (ML), medium (M), medium-high (MH), high (H), and very high (VH). Benthic cover was estimated for four different types of substrate: hard substrate/pavement, sand, rubble, and live hard (scleractinian) coral. The time of the benthic digital photos were set to the GMT time. There are approximately 200 pictures for each 50-minute towed survey track. The resolution at "Draft" quality (the lowest) is 72 pixels/inch. The resolution at "Best" quality (the highest) is 266 pixels/inch. The naming convention of benthic photos is ***MMDDYY_X_###.JPG, where *** is 3-letter abbreviation of the island or bank surveyed, MMDDYY is the local date of the towboard survey, X is the Xth dive on the day, and ### is the sequence number of the pictures taken for that particular dive. As an example, JAR032106_3_108.JPG means the picture was the 108th picture taken on 3rd dive of March 21, 2006 at Jarvis Island.
  1. How might this data set be cited?
    Coral Reef Ecosystem Division (CRED), Pacific Islands Fisheries Science Center (PIFSC), National Marine Fisheries Service (NMFS), National Oceanic and Atmospheric Administration (NOAA), 20120911, CRED Towed-Diver Benthic Characterization Survey at Rose, American Samoa in 2012.

    Online Links:

  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -168.17321036
    East_Bounding_Coordinate: -168.13742801
    North_Bounding_Coordinate: -14.5280902
    South_Bounding_Coordinate: -14.56076072
  3. What does it look like?
  4. Does the data set describe conditions during a particular time period?
    Beginning_Date: 18-Apr-2012
    Ending_Date: 19-Apr-2012
    Currentness_Reference: Ground Condition
  5. What is the general form of this data set?
    Geospatial_Data_Presentation_Form: spreadsheet
  6. How does the data set represent geographic features?
    1. How are geographic features stored in the data set?
    2. What coordinate system is used to represent geographic features?
      Horizontal positions are specified in geographic coordinates, that is, latitude and longitude. Latitudes are given to the nearest 0.0001. Longitudes are given to the nearest 0.0001. Latitude and longitude values are specified in Decimal Degrees. The horizontal datum used is World Geodetic System 1984 (WGS84).
      The ellipsoid used is Geodetic Reference System 80 (GRS80).
      The semi-major axis of the ellipsoid used is 6378137.
      The flattening of the ellipsoid used is 1/298.2572236.
      Vertical_Coordinate_System_Definition:
      Depth_System_Definition:
      Depth_Datum_Name: Local surface
      Depth_Resolution: 1
      Depth_Distance_Units: meters
      Depth_Encoding_Method: Explicit Depth Coordinate Included with Horizontal Coordinates
  7. How does the data set describe geographic features?

Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)
  2. Who also contributed to the data set?
    Jeff Anderson, Coral Reef Ecosystem Division (CRED); Matt Dunlap, Coral Reef Ecosystem Division (CRED)
  3. To whom should users address questions about the data?
    Coral Reef Ecosystem Division (CRED), Pacific Islands Fisheries Science Center (PIFSC), National Marine Fisheries Service (NMFS), National Oceanic and Atmospheric Administration (NOAA)
    NOAA IRC
    Honolulu, HI
    USA

    808 725-5360 (voice)
    808 725-5429 (FAX)
    nmfs.pic.credinfo@noaa.gov
    Contact_Instructions: e-mail preferred

Why was the data set created?

Part of a long-term monitoring program which documents the state of the reefs.

How was the data set created?

  1. From what previous works were the data drawn?
  2. How were the data generated, processed, and modified?
    Date: Unknown (process 1 of 1)
    The towboard survey involves a pair of scuba divers who are towed 60 m behind a small boat at a constant speed (~1.5 knots). The towboard survey is typically 50-min long and covers about 2 km of habitat, depending on the depth profile of the divers. The survey is divided into ten 5-min segments. During the survey, the benthic diver records percent cover of coral and macroalgae, estimates benthic habitat type and complexity, and censuses a suite of benthic macroinvertebrates including Crown of Thorns sea stars and sea urchins.
  3. What similar or related data should the user be aware of?

How reliable are the data; what problems remain in the data set?

  1. How well have the observations been checked?
    Observations were made by divers who are expert coral reef ecologists. Surveying in this habitat will greatly depend on the current, wave conditions, and field scheduling. The towed-diver survey is conducted one time per site per survey year; it is not replicated. Divers may change from year to year and by location.
  2. How accurate are the geographic locations?
    Although resource grade GPS units were used and a layback model was applied to the survey tracks, the exact survey positions were not physically marked and effort was not made to re-visit exact same tracks.
  3. How accurate are the heights or depths?
    SeaBird SBE-39 temp/depth recorder
  4. Where are the gaps in the data? What is missing?
    The towboard surveys are completed in forereef, backreef, and lagoon habitats. The minimum spatial resolution of the towboard survey is the 5-minute survey segment which covers approximately 200 m. As such, these surveys are appropriate for broad estimates but can not be used for fine scale, site-level data analysis.
  5. How consistent are the relationships among the observations, including topology?
    The same data collection protocols were used at each island or bank surveyed.

How can someone get a copy of the data set?

Are there legal restrictions on access or use of the data?
Access_Constraints: None
Use_Constraints:
Please cite CRED when using data. Coral Reef Ecosystem Division (CRED), Pacific Islands Fisheries Science Center (PIFSC), National Marine Fisheries Service (NMFS), National Oceanic and Atmospheric Administration (NOAA)
  1. Who distributes the data set? (Distributor 1 of 1)
    Coral Reef Ecosystem Division (CRED), Pacific Islands Fisheries Science Center (PIFSC), National Marine Fisheries Service (NMFS), National Oceanic and Atmospheric Administration (NOAA)
    Data Manager
    NOAA IRC
    Honolulu, HI
    USA

    808 725-5360 (voice)
    808 725-5429 (FAX)
    nmfs.pic.credinfo@noaa.gov
    Contact_Instructions: e-mail preferred
  2. What's the catalog number I need to order this data set? Offline Data
  3. What legal disclaimers am I supposed to read?
    While every effort has been made to ensure that these data are accurate and reliable within the limits of the current state of the art, NOAA cannot assume liability for any damages caused by errors or omissions in the data, nor as a result of the failure of the data to function on a particular system. NOAA makes no warranty, expressed or implied, nor does the fact of distribution constitute such a warranty.
  4. How can I download or order the data?
  5. Is there some other way to get the data?
    Contact CRED data management team for information
  6. What hardware or software do I need in order to use the data set?
    Contact CRED data management team for information

Who wrote the metadata?

Dates:
Last modified: 05-Jun-2019
Last Reviewed: 12-Sep-2012
Metadata author:
Coral Reef Ecosystem Division (CRED), Pacific Islands Fisheries Science Center (PIFSC), National Marine Fisheries Service (NMFS), National Oceanic and Atmospheric Administration (NOAA)
NOAA IRC
Honolulu, HI
USA

808 725-5360 (voice)
808 725-5429 (FAX)
nmfs.pic.credinfo@noaa.gov
Contact_Instructions: e-mail preferred
Metadata standard:
FGDC Content Standard for Digital Geospatial Metadata (FGDC-STD-001-1998)

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