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CRED Towed-Diver Benthic Characterization Surveys at Laysan Island, NW Hawaiian Islands in 2002

Metadata Updated: October 19, 2024

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 biennial Pacific Reef Assessment and Monitoring Program (RAMP) Cruises. 4 towboard surveys (7.2872 km in length), were conducted at Laysan Island during the NW Hawaiian Islands RAMP Cruise TC0207 from 8 September - 7 October 2002. 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., COT, 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 15m. 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 (>50cmTL) seen within 5m either side and 10m 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 15 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.

Access & Use Information

License: No license information was provided. If this work was prepared by an officer or employee of the United States government as part of that person's official duties it is considered a U.S. Government Work.

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Dates

Metadata Date May 26, 2024
Metadata Created Date October 19, 2024
Metadata Updated Date October 19, 2024
Reference Date(s) September 15, 2004 (publication)
Frequency Of Update ASNEEDED

Metadata Source

Harvested from CoRIS FGDC Metadata

Additional Metadata

Resource Type Dataset
Metadata Date May 26, 2024
Metadata Created Date October 19, 2024
Metadata Updated Date October 19, 2024
Reference Date(s) September 15, 2004 (publication)
Responsible Party Coral Reef Ecosystem Division (CRED), Pacific Islands Fisheries Science Center (PIFSC), National Marine Fisheries Service (NMFS), National Oceanic and Atmospheric Administration (NOAA) (Point of Contact)
Contact Email
Guid gov.noaa.crcp:cred_towboard_benthic_laysan_island_2002
Access Constraints Use Constraints: Please cite CRED when using the data. Coral Reef Ecosystem Division, Pacific Islands Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, Access Constraints: Data are available two years following data collection date.
Bbox East Long -171.675474
Bbox North Lat 25.803717
Bbox South Lat 25.697471
Bbox West Long -171.78032
Coupled Resource
Frequency Of Update ASNEEDED
Harvest Object Id 7e5a8d8c-4985-4c2e-9896-c75efd662d5d
Harvest Source Id d96f14c5-3e35-4b0a-a3b8-9392afeb50fa
Harvest Source Title CoRIS FGDC Metadata
Licence 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.
Lineage
Metadata Language eng; USA
Metadata Type geospatial
Old Spatial {"type": "Polygon", "coordinates": [[[-171.78032, 25.697471], [-171.675474, 25.697471], [-171.675474, 25.803717], [-171.78032, 25.803717], [-171.78032, 25.697471]]]}
Progress completed
Spatial Data Service Type
Spatial Reference System urn:ogc:def:crs:EPSG::4326
Spatial Harvester True
Temporal Extent Begin 2002-09-15
Temporal Extent End 2002-09-15

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