Benthic Surveys in Vatia, American Samoa since 2015: benthic images collected during belt transect surveys in 2015 and 2020

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.

These data were generated from benthic surveys undertaken in Vatia Bay to establish a comprehensive baseline, status, and trends for benthic composition and coral demographics, and are part of a broader NOAA Coral Reef Conservation Program (CRCP) funded project led by NOAA's National Centers for Coastal Ocean Science (NCCOS) and ESD to assess eutrophication impacts on coral ecosystem health in the bay. These efforts feed into the higher-level CRCP objectives by establishing an in-situ tracking system to assess the effects of management and mitigation strategies and activities in the target watersheds to reduce land-based sources of pollution.

Vargas-Angel B, Schumacher BD. 2018. Baseline surveys for coral reef community structure and demographics in Vatia Bay and Faga'alu Bay, American Samoa. Pacific Islands Fisheries Science Center, PIFSC Special Publication, SP-18-002, 38 p. https://doi.org/10.7289/V5/SP-PIFSC-18-002.

and

Vargas-Ángel B, Huntington B. 2020. Status and Trends Assessment of Benthic Coral Reef Communities in Vatia Bay, American Samoa, 2015–2020. Pacific Islands Fisheries Science Center, PIFSC Data Report, DR-20-020, 34p. https://doi.org/10.25923/r7dd-wg50, https://repository.library.noaa.gov/view/noaa/27437

Between 2015 and 2018, NOAA, NCCOS collected water quality sampling for nitrate, nitrite, ammonium, urea, total nitrogen, orthophosphorus, and total phosphorus data as part of this project to quantify the nutrient dynamics of the Bay. These additional data are described separately by the NOAA National Centers for Coastal Ocean Science (NCCOS); see citation below.

Whitall, D, M Curtis, A Mason, B Vargas-Angel. 2019. Excess Nutrients in Vatia Bay, American Samoa: Spatiotemporal Variability, Source Identification and Impact on Coral Reef Ecosystems. NOAA Technical Memorandum NOS NCCOS 266. Silver Spring. 69 pages. doi:10.25923/j8cp-x570

Raw data include 30 benthic photographs per survey site. Included in the archive package is a list of survey sites, including site id, location (latitude/longitude), and survey date, where photoquads were collected. The file naming convention for each photo/image is [SITE]_[YEAR]_[TRANSECT]_[PHOTO_NUMBER].JPG (for example: TUT-903_2012_A_01.JPG).

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.

Vatia Bay, Tutuila, American Samoa

Not applicable

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NOAA Coral Reef Ecosystem Sciences Division (ESD) Data Sharing Recommendations, version 9.0 updated August 12, 2015:

The ESD welcomes the opportunity to collaborate on research issues contributing to the scientific basis for better management of marine ecosystems. The ESD has a very diverse set of field activities that generates large volumes of data using an array of data collection protocols.

The following recommendations are for your consideration as you use this data:

1) Data analyses should take all field exigencies into account. The most effective way to do this would be active collaboration with ESD principal investigators.

2) In all presentations, product releases, or publications using data generated by ESD, proper acknowledgement of both ESD and the individuals responsible for data collection is expected. Citing the DOI (if available) is preferred, a non-DOI example is listed below.

3) If you collect or generate data for the same study areas, ESD requests that you share relevant information on complimentary data collections.

4) Those receiving data are strongly urged to inform the ESD Data Management Team of any errors and discrepancies that are discovered during the course of using these data. They are further urged to bring to the attention of the Team all problems and difficulties encountered in using these data. This information is necessary in order to improve the collections and to facilitate more efficient and economical data processing and retrieval. The users are asked to supply copies of any missing data that may be located, and to provide information as to significant subsets and special aggregations of data that are developed in using the material provided.

Example citation:

"This publication makes use of data products provided by the Coral Reef Ecosystem Sciences Division (ESD), Pacific Islands Fisheries Science Center (PIFSC), National Marine Fisheries Service (NMFS), National Oceanic and Atmospheric Administration (NOAA), with funding support from the NOAA Coral Reef Conservation Program (CRCP). The analysis and interpretations presented here are solely that of the current authors."

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

None

Please cite NOAA Ecosystem Sciences Division (ESD) when using the data.

Example

Cite as: Vargas-Angel, Bernardo; Ecosystem Sciences Division; Pacific Islands Fisheries Science Center (2022). Benthic Surveys in Vatia, American Samoa since 2015: benthic images collected during belt transect surveys in 2015 and 2020. [access date]

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PIFSC network/file system:

T:\Cruise\CruiseData\MP1602\Optical\TUT\REA\BENTHIC

T:\Cruise\CruiseData\MP2006\Optical\TUT\REA\BENTHIC

Benthic Image collection was conducted by experienced benthic survey personnel who have been trained.

Handheld GPS units were used to locate sites and mark site locations.

Not applicable

Site GPS location and depth are appropriately collected to allow spatiotemporal comparisons.

Complete; photoquads were taken at all sites surveyed. On occasions instrument malfunction or sea conditions may preclude the collection of 30 benthic images per site.

Only forereef, hard bottom habitats were surveyed.

Survey methods were consistent across all sites. Methods used in 2015 were slightly different from the current standard protocol used in 2020.

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.

NOAA IRC and NOAA Fisheries ITS resources and assets.

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).