Benthic Surveys in Faga'alu, American Samoa: benthic cover derived from analysis of benthic images collected during belt transect surveys of coral demography in 2015 and 2020

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 2015 and 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 benthic images and coral demography data are described and archived separately.

These data are part of a NOAA Coral Reef Conservation Program (CRCP) funded project aimed at establishing baseline data for benthic cover and composition via Rapid Ecological Assessment (REA) surveys conducted by the NOAA Ecosystem Sciences Division (ESD) (formerly Coral Reef Ecosystem Program -CREP) at Faga'alu Bay, Tutuila, American Samoa between 2012 and 2020.

In August 2012 Faga'alu watershed in American Samoa was adopted by the U.S. Coral Reef Task Force Watershed Partnership Initiative as a priority site, with the objective to reduce inputs of land-based sources of pollution to nearby coastal areas and coral reefs within the watershed. The Samoa Maritime rock quarry was found to be a major contributor to the periodic flux of excessive sediments onto the adjacent reef in Faga'alu. In September of December 2014, mitigation actions were implemented at the Samoa Maritime Quarry, including the installation of drainage systems, alternative ground cover, and retention ponds.

Data were collected to assess the effectiveness of management actions to reduce land-based sources of pollution impacts undertaken at the Samoa Maritime rock quarry. Pre-intervention baseline data were collected in 2013 and subsequent post-intervention monitoring in 2015 and 2020. Funding provided by the NOAA Coral Reef Conservation Program (CRCP) through two internal projects entitled. 1) Comprehensive Baseline Assessment and Pilot Test of Outcome Performance Measures in Faga'alu Bay, American Samoa, awarded to Suzie Holst. 2) Status and Trends Assessment for Land-based Sources of Pollution Impacts on Benthic Reef Communities in Faga'alu Bay and Vatia Bay, American Samoa, awarded to the NOAA Ecosystem Sciences Division.

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-Angel B, Huntington B. 2020. Status and trends assessments for land-based sources of pollution impacts on benthic reef communities in Faga'alu Bay, American Samoa. U.S. Dept. of Commerce, NOAA Technical Memorandum NOAA-TM-NMFS-PIFSC-109, 38 p. doi:10.25923/0gvj-zm69.

An Erosion and Sediment Control Plan was implemented at Samoa Maritime quarry to reduce excess sedimentation from quarry operations, and mitigation actions from the Plan took place in 2014 to install retention basins designed to stem the input of excess sediments into Faga'alu Stream below the quarry. REA surveys conducted by ESD in 2012 and 2013 serve as the pre-mitigation baseline, and surveys conducted in 2015 and 2020 document the downstream effects (e.g., changes to the coral community) in Faga'alu Bay from the mitigation efforts to reduce the sediment loads upstream.

Raw survey data includes metadata for each survey; site characteristics; unique image name and individual point observations identified at three functional group levels of benthic cover: Tier 1 (e.g., hard coral, macroalgae, etc.), Tier 2 (e.g., massive, branching, foliose, encrusting, etc.), and Tier 3 (e.g., Astreopora sp, Favia sp, etc.).

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.

Faga'alu Bay, Tutuila, American Samoa

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

CREP welcomes the opportunity to collaborate on research issues contributing to the scientific basis for better management of marine ecosystems. CREP 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 CREP principal investigators.

2) In all presentations, product releases, or publications using data generated by CREP, proper acknowledgement of both CREP 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, CREP requests that you share relevant information on complimentary data collections.

4) Those receiving data are strongly urged to inform the CREP 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 Program (CREP), 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.

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Please cite NOAA Coral Reef Ecosystem Program (CREP) when using the data.

Example

Cite as: Vargas-Angel, Bernardo; Ecosystem Sciences Division; Pacific Islands Fisheries Science Center (2022). Benthic Surveys in Faga'alu, American Samoa: benthic percent cover derived from analysis of benthic images collected during belt transect surveys of coral demography in 2015 and 2020. NOAA National Centers for Environmental Information. https://www.fisheries.noaa.gov/inport/item/32707

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PIFSC Oracle database view for benthic cover as calculated by annotations using CoralNet: MV_BIA_CNET_ANALYSIS_DATA

Data sets derived from image analysis are highly reliable within the stipulated taxonomic context. Each time a production run is performed for a region a calibration exercise is conducted by all staff that will participate in that round of image analysis classification. Usually 100-150 photos are selected from the photos being processed as part of the production run series, or other region-relevant photo streams. Then, image analysis software assigns 10 random fixed points per photo. Each photo analyst is asked to classify the same set of points in each of the photos used as part of the calibration exercise. The goal of the calibration exercise is to assess inter-observer variability. Inter-observer variability rates are available upon request for each production run.

The data set derived from the image analysis is as good as the images themselves; poor images with low contrast, inappropriate white balance, or out of focus may have to be discarded. Therefore, percent cover estimates for some sites may derive from differing number of images (points) between sites. Although the analysis process is statistically robust to allow for differing n (points) between sites, users should be aware of this limitation.

Classification is completed to the functional group/genus level (Tier 3).

Benthic images were collected during coral demographic surveys in 2012, 2015, and 2020 in Faga'alu; however, only the images collected during the most recent surveys in 2015 and 2020 were analyzed.

The same method of image analysis was used at each surveyed site.

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.

NOAA IRC and NOAA Fisheries ITS resources and assets.

The data described here were derived from the analysis of benthic images collected along photo-quadrat surveys by the NOAA Ecosystem Sciences Division (ESD):

In 2015 photo quadrat images were taken every meter from the 1-m to the 15-m mark along TWO, 18-m transects per site (n = 30 images).

In 2020 photo quadrat images were taken every meter from the 1-m to the 30-m mark along one 30-m transect line (n = 30 images).