This data package includes the source imagery of a benthic cover analysis for surveys performed in 2020 by the NOAA Ecosystem Sciences Division (ESD) in Vatia, American Samoa. The imagery described here was collected during belt transect surveys of coral demography by the ESD according to protocols established by the NOAA National Coral Reef Monitoring Program (NCRMP). In 2020 the survey implemented a one-stage stratified random sampling (StRS) design. Thirty images were collected at 24 stratified randomly selected sites in Vatia Bay. 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 cardinal position (i.e., north and south) and depth (i.e., shallow: >0–6 m and mid-depth: >6–18 m). Sampling effort allocation was determined based on strata area and sites randomly located within strata. The StRS design effectively reduces estimate variance through stratification using environmental covariates and by sampling more sites rather than more transects per site. Therefore, site-to-site comparisons should proceed with caution.

This data package includes benthic cover data of Aua Reef, American Samoa, produced from the analysis of benthic imagery performed by the Ecosystem Sciences Division (ESD) of the Pacific Island Fisheries Science Center (PIFSC), and funded by the Coral Reef Conservation Program (CRCP). Benthic imagery was collected at 18 randomly-selected sites during coral demographic surveys by the NOAA ESD during the 2022 fly-in mission to American Samoa (MP2206). After processing and sorting site photos, imagery was qualitatively analyzed using the web-based CoralNet image annotation tool. CoralNet projects random points on each image, and the benthic elements falling directly underneath each point are identified by trained scientists. The source imagery analyzed to produce benthic cover estimates are archived separately with the NOAA National Centers for Environmental Information (NCEI) in NCEI Accession 0270551.

The benthic cover data described herein were generated by the NOAA Ecosystem Sciences Division (former Coral Reef Ecosystem Program, CREP) from the quantitative analysis of photoquadrat benthic images using the image analysis software CoralNet, whereby random points are projected on each image and the benthic elements falling directly underneath each point are identified. The images were collected at sites in Faga'alu Bay in 2020 during belt transect surveys of coral demography. The data can be accessed online via the NOAA National Centers for Environmental Information (NCEI) Ocean Archive. The source imagery for this dataset are archived separately and accessible on NCEI.

Jurisdictional managers have expressed concerns that nutrients from the village of Vatia, Tutuila, American Samoa, are having an adverse effect on the adjacent coral reef ecosystem. Excess nutrient loads promote increases in algal growth that can have deleterious effects on corals, such as benthic algae outcompeting and overgrowing corals. Nitrogen and phosphorus can also directly impact corals by lowering fertilization success, and reducing both photosynthesis and calcification rates. Land-based contributions of nutrients come from a variety of sources; in Vatia the most likely sources are poor wastewater management from piggeries and septic systems. NOAA scientists conducted benthic surveys to establish a baseline against which to compare changes in the algal and coral assemblages in response to nutrient fluxes. The data described here were collected via belt transect surveys of coral demography (adult and juvenile corals) by the NOAA Coral Reef Ecosystem Program (CREP) according to protocols established by the NOAA National Coral Reef Monitoring Program (NCRMP). In 2015 data were collected at 18 stratified randomly selected sites in Vatia Bay. These data include: 1) an assessment of coral colony density and size-class distribution for the selected monitoring sites; 2) an assessment of coral recruitment at the monitoring sites; and 3) an evaluation of coral colony condition, including mortality, disease, bleaching, and evidence of sediment stress. These data can be accessed online via the NOAA National Centers for Environmental Information (NCEI) Ocean Archive. Additionally, photoquadrat benthic images were collected and analyzed for benthic cover composition (documented and archived separately). A brief report documenting the 2015 surveys conducted in Vatia and Fagaʻalu in Tutuila, American Samoa by the NOAA Coral Reef Ecosystem Program is in progress: Baseline Assessment of Coral Reef Community Structure and Demographics in Vatia and Fagaʻalu Bays, American Samoa.

This dataset describes the imagery collected in 2022 of Aua Reef, American Samoa by the Ecosystem Sciences Division (ESD) of NOAA, funded by the Coral Reef Conservation Program (CRCP), to study effects of land-based source pollution by establishing biological, physical, and chemical baselines. In September 2022, NOAA scientists conducted benthic survey protocols at 18 study sites in Aua, American Samoa. The surveys implemented a one-stage stratified random sampling (StRS) design and the survey domain encompassed the majority of the mapped area of reef and hard bottom habitats in the 0 to 6 m depth range. Photoquadrat benthic images were collected along belt transect surveys of coral demography according to protocols established by NOAA National Coral Reef Monitoring Program (NCRMP) in 2015. Thirty images were collected along one, haphazardly laid, 30-m transects. Still photographs were collected to record the benthic community composition at predetermined points along belt transect with a high-resolution digital camera mounted on a pole. Photographs were taken every 1 m from the 1 m to the 30 m mark. This work generates 30 photographs per site, which are later analyzed by ESD staff and partners using the computer program CoralNet. This analysis is the basis for estimating benthic cover and composition at each site, which is documented and archived separately. The StRS design effectively reduces estimate variance through stratification using environmental covariates and by sampling more sites rather than more transects per site. Therefore, site-to-site comparisons should proceed with caution.