Data Management Plan

The data described here result from benthic photo-quadrat surveys conducted along transects at stratified random sites across the Mariana archipelago in 2014, 2017, and 2022 as a part of Rapid Ecological Assessment (REA) surveys for corals and fish. Benthic habitat imagery were quantitatively analyzed using the Coral Point Count with Excel extensions (CPCe; Kohler and Gill, 2006) software from 2010-2014 and using the web-based annotation tool CoralNet (Beijbom et al. 2016) from 2015 to present. Images are analyzed to produce three functional group levels of benthic cover: Tier 1 (e.g., hard coral, soft coral, macroalgae, turf algae, etc.), Tier 2 (e.g., Hard Coral = massive, branching, foliose, encrusting, etc.; Macroalgae = upright macroalgae, encrusting macroalgae, bluegreen macroalgae, and Halimeda, etc.), and Tier 3 (e.g., Hard Coral = Astreopora sp, Favia sp, Pocillopora, etc.; Macroalgae = Caulerpa sp, Dictyosphaeria sp, Padina sp, etc.).

A stratified random sampling (StRS) design was employed to survey the coral reef ecosystems across the region. The survey domain encompassed the majority of the mapped area of reef and hard bottom habitats in the 0-30 m depth range. The stratification scheme included island, reef zone, and depth. Sampling effort was allocated based on strata area and sites were randomly located within strata. Sites were surveyed using photo-quadrats along transects to collect benthic imagery to ultimately produce estimates of relative abundance (benthic cover), frequency of occurrence, benthic community taxonomic composition and relative generic richness.

The StRS design effectively reduces estimate variance through stratification using environmental covariates and by sampling more sites rather than sampling more transects at a site. Therefore, site-level estimates and site to site comparisons should be used with caution.

Lineage Statement:
The stratified random sampling site (StRS) design and benthic photoquadrat survey methodology, employed by the PIFSC Ecosystem Sciences Division (ESD) since 2013. Benthic imagery is collected at stratified random sites. The imagery is annotated using Coral Point Count with Excel Extentions (CPCe) or CoralNet to derive benthic cover values.

Process Steps:

• A stratified random sampling (StRS) design was employed to survey the coral reef ecosystems through the U.S. Pacific regions. The survey domain encompassed the majority of the mapped area of reef and hard bottom habitats. The stratification scheme included island, reef zone, and depth in all regions, as well as habitat structure type in the Main Hawaiian Islands. The habitat structure types included simple, complex, and coral-rich. Depth categories of shallow (0-6 m), mid (> 6-18m) and deep (>18-30 m) were also incorporated into the stratification scheme. Allocation of sampling effort was proportional to strata area. Sites were randomly selected within each stratum. A geographic information system (GIS) and digital spatial databases of benthic habitats (NOAA National Centers for Coastal Ocean Science NCCOS), reef zones (IKONOS satellite imagery, NDGC 1998) bathymetry (NDGC 1998, CREP benthic mapping data), and marine reserve boundaries (NOAA) were used to facilitate spatial delineation of the sampling survey domain, strata, and sample units. Map resolution was such that the survey domain could be overlain by a grid using a GIS with individual cells of size 50 m by 50 m in area. A two-stage sampling scheme following Cochran (1977) was employed to control for spatial variation in population parameters at scales smaller than the grid cell minimum mapping unit (2,500 m2). Grid cells containing hard-bottom reef habitats were designated as primary sample units (referred to as sites). (Citation: Lozada-Misa P, Schumacher BD, Vargas-Angel B. 2017. Analysis of benthic survey images via CoralNet : a summary of standard operating procedures and guidelines. Pacific Islands Fisheries Science Center, PIFSC Administrative Report, H-17-02, 169 p. https://doi.org/10.7289/V5/AR-PIFSC-H-17-02.)
• Photoquadrat surveys were conducted by both the fish and benthic teams. Still photographs were collected to record the benthic community composition at predetermined points along the transect lines with a high-resolution digital camera mounted on a pole. Overall, 30 photoquadrat images are collected at each site. The fish team conducts these surveys along one 30 meter transect that spans the length of two stationary point count (SPC) cylinders used to assess fish abundance (30 images total, Rep A). Benthic substrate photos are taken at one meter intervals along the right hand side of the 30 m transect line. The benthic team conducts the photoquadrat surveys along two, independent 18 meter transects. Photos of the benthic substrate are taken at one meter intervals starting at meter 1, along the left hand side of each 18 meter transect (15 images/transect; 30 images total; Rep A and B). (Citation: Lozada-Misa P, Schumacher BD, Vargas-Angel B. 2017. Analysis of benthic survey images via CoralNet : a summary of standard operating procedures and guidelines. Pacific Islands Fisheries Science Center, PIFSC Administrative Report, H-17-02, 169 p. https://doi.org/10.7289/V5/AR-PIFSC-H-17-02.)
• The benthic photoquadrat imagery that are collected as part of the Rapid Ecological Assessment (REA) surveys for coral and fish are analyzed by using Coral Point Count with Excel extensions (CPCe; Kohler and Gill 2006) software through 2014 or by using the web-based annotation tool CoralNet (Beijbom et al. 2016) from 2015 to present. CPCe or CoralNet assigns 10 random points per photo and the benthic elements falling directly underneath each point is identified to three functional group levels: Tier 1 (e.g. hard coral, soft coral, macroalgae, turf algae, etc.), Tier 2 (e.g. Hard coral by morphology = massive, branching, foliose, encrusting, etc.; Macroalgae = upright macroalgae, encrusting macroalgae, bluegreen macroalgae, and Halimeda, etc.), and Tier 3 (e.g. Hard coral by genus and morphology; Macroalgae by genus or grouped genera). The detailed list of each functional group level or tier is included in the benthic image analysis classification scheme. (Citation: Lozada-Misa P, Schumacher BD, Vargas-Angel B. 2017. Analysis of benthic survey images via CoralNet : a summary of standard operating procedures and guidelines. Pacific Islands Fisheries Science Center, PIFSC Administrative Report, H-17-02, 169 p. https://doi.org/10.7289/V5/AR-PIFSC-H-17-02.)
• Raw survey data includes unique image name and individual point observations identified at three functional group levels of benthic cover with the corresponding physical data which reflect the description of the site. The physical data for all records includes the following: region, island, site, date (day, month, year), latitude (dd), longitude (dd), reef zone, habitat type, depth category, minimum depth and maximum depth. (Citation: Lozada-Misa P, Schumacher BD, Vargas-Angel B. 2017. Analysis of benthic survey images via CoralNet : a summary of standard operating procedures and guidelines. Pacific Islands Fisheries Science Center, PIFSC Administrative Report, H-17-02, 169 p. https://doi.org/10.7289/V5/AR-PIFSC-H-17-02.)

Quality control is enforced by means of point-to-point, inter-observer calibration exercises that are conducted before each image analysis production series. Training modules and standard operating procedures have also been developed and documented to ensure improved performance and consistent imagery analysis results produced by multiple analysts.

Data can be accessed online via the NOAA National Centers for Environmental Information (NCEI) Ocean Archive.

NOAA IRC and NOAA Fisheries ITS resources and assets.