Data Management Plan

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 land-based sources of pollution, including nutrient fluxes.

Photoquadrat benthic images were collected in 2015 and 2020 only, via belt transect surveys of coral demography according to protocols established by NOAA National Coral Reef Monitoring Program (NCRMP) in 2015.

In 2015, the survey implemented a two-stage stratified random sampling (StRS) design to assess the Vatia benthic coral reef community, and a one-stage StRS design in 2020. 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.

Vatia Bay, Tutuila, American Samoa

Lineage Statement:
Benthic photographs were collected during belt transect surveys of corals by the NOAA Ecosystem Sciences Division (ESD) following the same protocol to that established by the NOAA National Coral Reef Monitoring Plan (NCRMP).

Process Steps:

• In 2015, the survey implemented a two-stage stratified random sampling (StRS) design. 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. At each site, belt-transects were the focal point of the biological surveys. In 2015, fifteen images were collected along each, two haphazardly laid, 18-m transects. Still photographs were collected to record the benthic community composition at predetermined points along belt transects with a high-resolution digital camera mounted on a pole. Photographs were taken every 1 m from the 1 m to the 15 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. In 2016, American Samoa Department of Marine and Wildlife Resources (DMWR) collected benthic images approximately every 3 months at five shallow sites where permanent transects were established. DMWR forwarded the images to ESD for analysis and assess temporal changes in benthic cover. These data are reported separately. Survey protocols followed the National Coral Reef Monitoring Program methodologies historically implemented by NOAA's Ecosystem Sciences Division. (Citation: Ecosystem Sciences Division Standard Operating Procedures: Data Collection for Rapid Ecological Assessment Benthic Surveys, 2019 Update)
• In 2020 the survey implemented a one-stage stratified random sampling (StRS) design. 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. One, haphazardly laid, 30-m belt-transect was the focal point of the photoquadrat survey in 2020, Still photographs were collected to record the benthic community composition with a high-resolution digital camera mounted on a pole. Thirty photographs were taken every meter from the 1 m to the 30 m. This work generates 30 photographs per site, which are later analyzed by ESD staff and partners using the computer program CoralNet. Survey protocols followed the National Coral Reef Monitoring Program methodologies historically implemented by NOAA's Ecosystem Sciences Division. (Citation: Ecosystem Sciences Division Standard Operating Procedures: Data Collection for Rapid Ecological Assessment Benthic Surveys, 2019 Update)

Instrumentation and camera setting are updated periodically to improve image quality.

An optical validation QC procedure is employed to verify number of images, per site and file name. Also, image color correction is implemented to improve image quality.

Benthic images and the file structure are quality controlled by CREP personnel before they are migrated and integrated into CREP's master optical directory on the PIFSC network.

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

NOAA IRC and NOAA Fisheries ITS resources and assets.