Benthic surveys along a water quality gradient in Aua, American Samoa: benthic cover derived from analysis of benthic images collected in 2022

This metadata record describes the benthic cover data of Aua Reef, American Samoa, produced from the benthic imagery analysis 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 as well as coral demography data are described and archived separately, see 'Related Items' below.

Data from benthic surveys of Aua Reef establishes a comprehensive biological baseline for land-based sources of pollution impacts on benthic composition and coral demography. 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 impacts on coral reefs.

The focal point of this project was to establish a biological and water quality and carbonate chemistry baseline for Aua reef. This work was aimed at identifying measurable spatial differences in the structure and composition of the benthic and coral community at Aua that can be explained by measurable spatial patterns of water quality (nutrients and sediments) and water carbonate chemistry (pH and Alkalinity). This work is of fundamental importance for the development of the Aua Watershed Management Plan, and will enable Federal and jurisdictional resource managers to more effectively assess the effectiveness of watershed management actions reducing land-based pollution and impacts to the adjacent coral reef ecosystems.

Lozada-Misa P, Schumacher BD, Vargas-Angel B. 2017. Analysis of benthic survey images via CoralNet : a summary of standard operating procedures and guidelines. Pacific Islands Fisheries Science Center, PIFSC Administrative Report, H-17-02, 169 p. https://doi.org/10.7289/V5/AR-PIFSC-H-17-02.

This project builds on prior baseline and status and trends assessments conducted in 2012, 2015, and 2020 in Faga'alu Bay (U.S. Task Force watershed priority site) and Vatia (Territorial priority watershed) to address National and Jurisdictional goals to reduce land-based sources of pollution impacts in coral reef ecosystems.

This baseline assessment for land-based sources of pollution on Aua reef is part of a larger CRCP-funded project ID 31303: "Linking watershed management activities to reef health in American Samoa".

CTD profiles and water samples also were collected as part of this baseline assessment for the analysis of particulate and dissolved nutrients, total suspended solids, chlorophyll-a, and seawater pH and Alkalinity. These data are documented and archived separately.

Data file for 2022 Aua benthic cover data set was updated in Februrary 2023; annotations of images that previously fell into 'unidentifiable' category on CoralNet (due to shading) were re-analyzed, and 125 annotations of the 5400 total were updated.

Raw survey data includes metadata for each survey (where, when, who, area); site characteristics (depth, reef type, habitat); unique image name and individual point observations identified at three functional group levels of benthic cover: Tier 1 (e.g., hard coral, soft coral, macroalgae, turf algae, etc.), Tier 2 (e.g., Hard Coral = massive, branching, foliose, encrusting, etc.; Macroalgae = upright macroalgae, encrusting macroalgae, bluegreen macroalgae, and Halimeda, etc.), and Tier 3 (e.g., Hard Coral = Astreopora sp, Favia sp, Pocillopora, etc.; Macroalgae = Caulerpa sp, Dictyosphaeria sp, Padina sp, etc.).

A data dictionary is included to define columns in the dataset (https://www.fisheries.noaa.gov/inport/item/68576). An image classification scheme is also included to describe the classification used with the CoralNet annotation tool (https://www.fisheries.noaa.gov/inport/item/68575).

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.

Aua reef, Tutuila, American Samoa

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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 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.

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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 Aua, American Samoa: benthic percent cover derived from analysis of benthic images collected during belt transect surveys of coral demography in 2022. NOAA National Centers for Environmental Information.

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PIFSC Oracle database view: MV_BIA_CNET_ANALYSIS_DATA

SELECT *

FROM MV_BIA_CNET_ANALYSIS_DATA

WHERE OBS_YEAR = 2022

AND SITE IN (SELECT SITE FROM LIST_OF_SITES WHERE COMMENT_ = 'AUA')

Benthic Images were analyzed by experienced benthic survey personnel who have been trained. Benthic composition data sets derived from image analysis are highly reliable within the stipulated taxonomic context.

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 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 1-Tier 3).

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 methodology to analyze benthic imagery using CoralNet to derive benthic cover values.

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