Coral Bleaching & Recovery Observations using Structure-from-Motion (SfM) Models from Main Hawaiian Islands Fixed Sites Surveyed from 2019 to 2021

Coral adult demographic data described in this dataset are derived from the GIS analysis of benthic photomosaic imagery. This data includes coral species identification, bleaching extent and severity, colony diameter, perimeter, and planar size. The source imagery was collected using a Structure from Motion (SfM) approach during in-water surveys conducted by divers and is documented and described separately. The data was collected by the NOAA Pacific Islands Fisheries Science Center (PIFSC) Ecosystem Sciences Division (ESD; formerly the Coral Reef Ecosystem Division) and [on Hawaii Island] in partnership with State of Hawaii Department of Land and Natural Resources (DLNR), Division of Aquatic Resources (DAR) during the 2019 bleaching event in the Main Hawaiian Islands, and in subsequent years (2020, 2021) to assess recovery. The SfM surveys were conducted at fixed sites ranging in depth from 18-52'. Sites were photographed using underwater cameras for later processing using one of two SfM approaches: using a spiral swim pattern (where divers take images continuously in a circular pattern covering a circle of 12m diameter), or within a defined box where divers swam back and forth to cover a 10 x 10m area. The photographs were processed using Agisoft Metashape software to generate orthomosaic images that were analyzed in ArcGIS for adult coral colony demographic metrics. Data was collected for each site within at least 10 randomly generated 0.49m2 quadrats. Additional quadrats were analyzed if necessary until the sample sizes per species of interest were met. If a species had very low density at a given site (< 10 patches recorded within the first 10 quadrats), it was dropped from further observations. However, the data for these patches remains in the raw data in order to provide presence/absence data. Therefore, data should be carefully analyzed to ensure accurate species density calculations are done. Two datasets are provided: an annotations file which provides coral demographic information of 6 target species at 12 fixed sites across 3 years, as well as a site metadata file which describes the site and surveys which were used to generate models for which annotation data was derived.

Six species were assessed: Montipora capitata (MCAP), Montipora patula (MPAT), Porites lichen (PLIC), Porites lobata (PLOB), Porites lutea (PLUT), and Pocillopora meandrina (PMEA). Annotations included coral species identification, maximum diameter measurement, planar area measurement, morphology, and, for sites surveyed in 2019, bleaching extent and bleaching severity. Each coral was annotated at the patch level, and patches composing individual colonies, also known as genets, were assigned a unique genet ID number. The same coral patches were tracked over each time point, unless mortality of a coral patch occurred.

Note an update in methodology: The data was collected in two stages. During the first stage of data collection that was completed in 2021, for each coral patch, (>= 5cm in diameter), maximum diameter, ID (to lowest taxonomic level), morphology, bleaching extent (% of the patch with reduced pigmentation), and bleaching severity (1-3 from least to most severe) were recorded. In 2023 the methodology was updated for the second stage of data collection; the updated dataset includes measures of planar area and a "genet" (colony) identification column. The 2023 dataset was also collected following an update to the model process methodology (see Lineage). Users should refer to the most updated dataset published in 2023.

The Hawaii Coral Bleaching Collaborative (HCBC) planned and executed a field survey response in 2019 that applied a structured, hypothesis-driven approach to document the extent of coral bleaching in the Hawaiian Archipelago, and laid the groundwork for tracking coral response and recovery through time. Fixed sites were revisited in 2020 and 2021 to examine survivorship, recovery, and growth following the 2019 bleaching event. The purpose of the Structure from Motion (SfM) surveys throughout the Main Hawaiian Islands is to efficiently and effectively collect coral demographic data.

This was funded by two CRCP Projects: #31283, #31361

titled 'Assessing impacts of Hawaii's 2019 coral bleaching event on coral recovery and coral communities' and 'Hawai'i coral bleaching assessment and analysis'

Suka R, Asbury M, Couch C, Gray A, Winston M, Oliver T. 2019. Processing Photomosaic Imagery of Coral Reefs Using Structure-from-Motion Standard Operating Procedures. U.S. Dept. of Commerce, NOAA Technical Memorandum NOAA-TM-NMFS-PIFSC-93, 54 p. doi:10.25923/h2q8-jv47

Rodriguez C, Amir C, Gray A, Asbury M, Suka R, Lamirand M, Couch C, Oliver T. 2021. Extracting Coral Vital Rate Estimates at Fixed Sites Using Structure-from-Motion Standard Operating Procedures. U.S. Dept. of Commerce, NOAA Technical Memorandum NOAA-TM-NMFS-PIFSC-120, 80 p. p. doi: https://doi.org/10.25923/a9se-k649

In 2023 this data was republished after 2019 - 2021 imagery was re-annotated with an updated methodology; refer to most recent published dataset (2023); prior to 2023 this metadata record described only the preliminary 2019 dataset, and was titled 'Colony-level annotations using Structure-from-Motion models from sites surveyed across the Main Hawaiian Islands during the 2019 bleaching event'.

As more data is generated with this methodology, datasets will be added to this metadata record.

Dataset includes metadata for each Structure from Motion (SfM) survey site (survey date, geographic coordinates, depth); individual adult coral observations identified to the lowest taxonomic level possible (species) including morphology, maximum diameter, bleaching extent and bleaching severity.

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.

Hawaiian Archipelago October 8 2019 - July 20 2021

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

ESD welcomes the opportunity to collaborate on research issues contributing to the scientific basis for better management of marine ecosystems. 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 Science 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 Fisheries, Ecosystem Science Division (ESD) when using the data.

Example:

Ecosystem Science Division; Pacific Islands Fisheries Science Center, 2023: Coral Bleaching & Recovery Observations using Structure-from-Motion (SfM) Models from Main Hawaiian Islands Fixed Sites Surveyed from 2019 to 2021, https://www.fisheries.noaa.gov/inport/item/65764.

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A GPS unit is used to record the location of each Structure from Motion (SfM) survey site. A Nikon SL2 DSLR digital camera in an Ikelite underwater housing was used to take photographs of each site. Coded markers 0.25-0.50 m long were used underwater to provide a scale for the mosaic imagery. Mosaic images were created and scaled using Agisoft Metashape (version 1.6.2 build 10247). Models were further scaled using Viscore software. Sampling boundaries and coral demographic measurements were created in ArcGIS Pro (version 2.6.0).

The data set derived from the imagery is only as good as the images themselves; Images with poor resolution, poor lighting, extraneous objects (fins, etc), or blur were excluded from analysis.

Handheld GPS units were used to locate fixed sites and update site locations if needed.

Prior to conducting surveys, the SfM image collector was trained to swim in a back-and-forth or circular pattern to collect imagery with 60-80% overlap. Both classroom and field training were completed before any surveys were conducted. This training ensures that all SfM image collection was conducted consistently during the mission.

Coral demographic data was extracted by SfM image annotators that had been trained, underwent a series of calibration efforts and testing on coral taxon identification testing, morphology, and condition assessment. All annotators met a set of minimum standards for coral demographic data collection.

Of the fixed sites for which SfM imagery was collected at during the 2019 bleaching survey effort, a subset of these sites were annotated that included 5 from Hawaii Island, 5 from Oahu, and 2 from Lanai.

The same method of annotation was used for all SfM imagery.

Prior to generating the 3D dense point clouds and 2D orthomosaics, the JPEG imagery was evaluated for image quality and images deemed unsatisfactory (e.g. overexposed, images of blue water or images of divers, or images not taken perpendicular to the reef) were removed from the image set. During annotation in ArcMap, the original JPEG imagery was viewed alongside the orthomosaic using Agisoft or Viscore Image View feature to see fine scale colony details, observe colonies from multiple angles and locate colonies not visible in the orthomosaic. Annotations created in ArcMap were quality controlled using a multi-stage process. Data were quality controlled in R with specific queries to identify and correct data entry errors (e.g. misspelled species names, missing segments, data in incorrect columns, % bleaching >100%).

NOAA IRC and NOAA Fisheries ITS resources and assets.

Benthic imagery was collected at permanent sites and generated into 3D dense point clouds (DPCs) using Agisoft Metashape software. DPCs from the same site, but different collection dates were converted into 2D orthomosaics and scaled, oriented and aligned together. Orthomosaics were sub-sampled by randomly distributing quadrats throughout the orthopmosaic. Quadrat location was conserved across all orthomosaics associated with the same permanent site. Target coral species were identified within each quadrat and their perimeters were annotated until a sufficient sample size of each species was recorded. Annotations included coral species identification, maximum diameter measurement, planar area measurement, morphology, and, for sites surveyed in 2019, bleaching extent and bleaching severity. Each coral was annotated at the patch level, and patches composing individual colonies, also known as genets, were assigned a unique genet ID number. The same coral patches were tracked over each time point, unless mortality of a coral patch occurred.