Data Management Plan

Data provided in his dataset are benthic habitat imagery that result from benthic photo-quadrat surveys conducted along transects at stratified random sites surveyed across the Main Hawaiian Islands during the 2019 bleaching event. The data were collected by the NOAA Ecosystem Sciences Division (ESD) during a multi-institutional effort by the Hawaii Coral Bleaching Collaborative (HCBC) to build a comprehensive dataset of the spatial extent and severity of bleaching in the Hawaiian Archipelago during the peak of the forecasted 2019 coral bleaching event. These photo-quadrat surveys were conducted during shore-based missions and at each site, rapid visual assessments were also conducted to provide information on live coral cover and the percentage and average severity that was bleached, as well as taxa-specific metrics (live cover and the percentage and severity that was bleached).

A stratified random sampling (StRS) design was employed to select random sites. 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 in all regions, as well as habitat structure type in the Main Hawaiian Islands. 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 (percent 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.

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

Main Hawaiian Islands (MHI), including Hawaii, Maui, Oahu, and Lanai.

Lineage Statement:
The stratified random sampling (StRS) design and benthic photoquadrat survey methodology has been employed by the NOAA Ecosystem Sciences Division since 2013. These photos are color-corrected (if necessary) prior to analysis. The data management team also uses a optical validation script to re-name photos and enforce several validation checks.

Process Steps:

• A stratified random sampling (StRS) design was employed to conduct surveys during the 2019 bleaching event by the NOAA Ecosystem Sciences Division. 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). NOAA Fisheries Ecosystem Sciences Division (ESD) conducted rapid visual assessments and photoquadrat assessments of coral bleaching using the methodology outlined by the NOAA Coral Bleaching standard operating procedure for 2019. Still photographs were collected to record the benthic community composition at predetermined points along the transect lines with a high-resolution digital camera. Overall, 30 photoquadrat images are collected at each site. Benthic substrate photos are taken at one meter intervals along the right hand side of the 30 m transect line. Raw data include 30 benthic photographs per survey site. Included in the archive package is a list of survey sites, including region, island, site, date (day, month, year), latitude (dd), longitude (dd), and depth (ft) where photoquads were collected and unique image name. The file naming convention for each photo/image is [SITE]_[YEAR]_[TRANSECT]_[PHOTO_NUMBER].JPG (for example: TUT-903_2012_A_01.JPG).

The photos are reviewed by the diver for accuracy and usability. The data management team also uses a optical validation script to re-name photos and enforce several validation checks. Images are color corrected prior to analysis.

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

The images reside on a file server maintained and regularly backed up by PIFSC ITS.