Benthic Images from Towed-Diver Surveys in the Main Hawaiian Islands to Assess the Mass Coral Bleaching Event in November 2015

A team from the Pacific Islands Fisheries Science Center (PIFSC), Coral Reef Ecosystem Program (CREP) deployed on a two-week research cruise in November 2015 to evaluate the impacts of the 2015 mass coral bleaching event in the Main Hawaiian Islands via towed-diver surveys. Areas surveyed included south Oahu, west Maui, Lana’i, and west Hawaii island. Over the course of 10 survey days, the team surveyed approximately 90 km of 15-m wide transects at depths ranging from 2 to 10 m.

Data provided in this dataset include benthic images that were collected during the towed-diver surveys from a camera that was mounted to the towboard. A downward-facing DSLR camera with strobes collected these photographic quadrat data by capturing an image of the benthos at 15-second intervals during the surveys.

Two additional datasets were collected during the surveys and are documented separately. Towed divers recorded visual estimates of percentage of live coral that was pale and bleached, as well as presence/absence data of condition by generic composition. Oceanographic data was collected continuously throughout each survey with a suite of sensors mounted to the towboard recording conductivity, temperature, depth, flourometry (chlorophyll-a), turbidity and dissolved oxygen.

The benthic images can be accessed online via the NOAA National Centers for Environmental Information (NCEI) Ocean Archive.

The 2014–2015 global coral bleaching event brought widespread and severe impacts to the entire Hawaiian archipelago. In 2015, the corals of the Main Hawaiian Islands were subjected to unprecedented levels of thermal stress that resulted in the most severe coral bleaching ever recorded in the islands. To report on the event, local researchers and reef managers conducted free-swimming diver surveys in areas generally accessible via same-day field excursions. In an effort to survey larger high coral cover areas that are difficult for local researchers and managers to access via day-long field trips, a team from CREP deployed on a two-week research cruise in November 2015 aboard the NOAA ship Hi‘ialaka‘i to evaluate the impacts of the 2015 coral bleaching event in the Main Hawaiian Islands via towed-diver surveys.

As of September 2016, CREP is collaborating with academic researchers at Bangor University to analyze this photo-quadrat collection.

Raw data includes approximately 200 benthic photographs per tow. Included in the archive package is a list of tows documenting the mid-point of each tow along which the photographs were collected. The file naming convention for each photo/image is [ISLANDCODE][MMDDYY]_[DIVEID]_[PHOTO_NUMBER].JPG (for example: OAH111815_1_001.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.

Main Hawaiian Islands

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NOAA 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.

Suggested citation:

Coral Reef Ecosystem Program; Pacific Islands Fisheries Science Center (2016). Benthic Images from Towed-Diver Surveys in the Main Hawaiian Islands to Assess the Mass Coral Bleaching Event in November 2015. NOAA National Centers for Environmental Information. https://www.fisheries.noaa.gov/inport/item/32587

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The latitude and longitude coordinates of the survey track are recorded using a Global Positioning System (GPS) receiver on-board the tow boat. The survey track is georeferenced and a layback model is applied (python script in ESRI ArcGIS for Desktop) that more accurately maps the positions of the recorded observations.

This survey effort specifically targeted areas of known high coral coverage to evaluate bleaching impact. Although efforts are made to include broad spatial coverage of high coral cover areas at each island, poor weather and sea conditions prevented the team from surveying various reef areas. On rare occasions, battery failure and accidental alteration of optimal exposure settings resulted in partial loss of benthic images for some survey segments.

Images captured from the towboard-mounted DSLR camera may not contain a clear depiction of the benthos due to a number of confounding factors, including the angle of the camera lens in relation to the benthos, the distance between the camera lens and the benthos, water turbidity and occasional malfunction of the synchronized strobes.

Images were taken on all towboard surveys.

Benthic photoquadrat images captured during towboard surveys serve as consistent and objective visual documentation of the benthos during the surveys.

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 towed-diver surveys of corals by the NOAA Coral Reef Ecosystem Program (CREP) following the same protocol to that established by the NOAA National Coral Reef Monitoring Program (NCRMP).