National Coral Reef Monitoring Program: Towed-diver Surveys of Benthic Habitat, Key Benthic Species, and Marine Debris Sightings of the Pacific Remote Island Areas since 2014

The towed-diver method is used to conduct benthic surveys, assessing large-scale disturbances (e.g., bleaching) and quantifying benthic components such as habitat complexity/type and the general distribution and abundance patterns of live coral, crustose coralline algae (CCA), macroalgae, and macroinvertebrates. Surveys are conducted in the Hawaiian and Mariana Archipelagos, American Samoa, and the Pacific Remote Island Areas as part of the NOAA National Coral Reef Monitoring Program (NCRMP). A suitable method for assessing relatively large areas of reef habitat, the method involves towing a pair of SCUBA divers—one benthic and one fish—behind a small boat for approximately 50 min following the ~15-m depth contour and covering about 2–3 km of habitat. Each diver is equipped with a towboard and attempts to maintain a constant elevation above the surface of the reef (~1 m) for the duration of the survey. A complete towed-diver survey is divided into 10, 5-min segments, with visual observations recorded by 5-min segment.

The visual estimate data provided in this dataset were collected during towed-diver surveys which includes percentage cover of total live hard corals, stressed hard corals, soft corals, sand, coralline algae, and macroalgae, and the number of individual macroinvertebrates (crown of thorns starfish (COTS), sea urchins, and giant clams). Benthic habitat complexity and type data are also collected as part of the survey with the following habitat type categories: continuous reef, spur and groove, patch reefs, rock boulders, pavement, rubble flat, sand flats, pinnacle, and wall.

The data were collected around the Pacific Remote Island Areas as part of the NOAA Pacific Islands Fisheries Science Center (PIFSC), Coral Reef Ecosystem Program (CREP) led missions since 2014. These data can be accessed online via the NOAA National Centers for Environmental Information (NCEI) Ocean Archive.

The National Coral Reef Monitoring Program (NCRMP) details an integrated ecosystem approach to provide a consistent flow of information to assess and report the status and trends of environmental conditions, living reef resources, and the people and processes that interact with coral reef ecosystems. Although the scope of NCRMP is broad, it is intended to assess the status of coral reef ecosystems and their conditions throughout U.S. States and Territories and provide a steady and comprehensive analytical context to gauge changes in conditions at the sub-jurisdictional scale of an island or atoll.

Through the implementation of the NCRMP, NOAA is able to clearly and concisely communicate results of national-scale monitoring to Federal, State, and Territorial policy makers, resource managers, scientists, and the public on a periodic basis.

Lino K, Asher J, Ferguson M, Gray A, McCoy K, Timmers M, Vargas-Ángel B (2018) Ecosystem Sciences Division standard operating procedures: data collection for towed-diver benthic and fish surveys. Pacific Islands Fish. Sci. Cent., Natl. Mar. Fish. Serv., NOAA, Honolulu, HI 96818-5007. Pacific Islands Fish. Sci. Cent. Admin. Rep. H-18-02, 76 p.

The National Coral Reef Monitoring Program (NCRMP) is a framework for conducting sustained observations of biological, climate, and socioeconomic indicators at 10 priority coral reefs across the U.S. and its territories. This integrated approach will consolidate monitoring of coral reefs under a uniform method in the Pacific, Atlantic, Caribbean, and the Gulf of Mexico for the first time. NCRMP is funded by the CRCP and supported by NOAA Fisheries, NOAA National Centers for Coastal Ocean Science (NCCOS), and many other partners. The Coral Reef Ecosystem Program (CREP) at NOAA Fisheries is leading biological monitoring in the U.S. Pacific Islands Region.

The biological component of NCRMP in the Pacific provides a triennial ecological characterization at a broad spatial scale of general reef condition for reef fishes, corals and benthic habitat (i.e., fish species composition/density/size, benthic cover, and coral density/size/condition). Each year, CREP scientists work closely with CRCP and local partners to collect biological data on fish populations and coral reef communities from strategically selected sites during Reef Assessment and Monitoring Program (RAMP) missions. Innovative analysis techniques are then used to develop products that give fellow scientists, managers, decision makers and the public a better understanding of a region’s resources and how they are changing over time.

Raw survey data includes metadata for each survey (where, when, who, length, duration, depth, reef type, temperature); and benthic observations.

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.

Pacific Remote Island Areas (PRIA)

Not applicable

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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). National Coral Reef Monitoring Program: Towed-diver Surveys of Benthic Habitat, Key Benthic Species, and Marine Debris Sightings of the Pacific Remote Island Areas since 2014. NOAA's National Centers for Environmental Information, https://www.fisheries.noaa.gov/inport/item/5567.

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PIFSC Oracle database view: VS_BENT_TDS

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.

The towed-diver surveys are completed in forereef, backreef, and lagoon habitats. Considering that the towed divers are covering ~200 m during each 5-min time frame of a 50-minute survey, benthic coverage calculations are broad estimates. These data can be used to see large differences but can not be processed to a fine scale.

Observations during each tow were made by trained divers. The visual variation throughout the tow may change drastically as well as current and surface conditions for the support vessel impacting the preferred depth contour and accompanying track lines.

The percentage cover for the different benthic elements are binned within 1 of 10 classification categories. NOAA PIFSC CREP’s use of the 10-category method is similar to AIMS, whereby percent cover of living hard coral, stressed coral, soft coral, macroalgae, crustose coralline algae, sand, and rubble are calculated from towed-diver results by representing each cover category through the midpoint of its range. Note that the total percentage cover will not add up to 100%, as several habitat categories (e.g., rock, pavement, etc) are not included.

Benthic cover categories and the corresponding percentage range bins are as follows:

Category 1: 0.1 -1 %

Category 2: 1.1 - 5 %

Category 3: 5.1 - 10 %

Category 4: 10.1 - 20 %

Category 5: 20.1 - 30 %

Category 6: 30.1 - 40 %

Category 7: 40.1 - 50 %

Category 8: 50.1 - 62.5 %

Category 9: 62.6 - 75 %

Category 10: 75.1 - 100 %

Macroinvertebrates are counted independently up to 25 individuals. Above that, numbers of each macroinvertebrate taxa are binned as follows:

Category 1: 26 – 50

Category 2: 51 – 100

Category 3: 101 – 250

Category 4: 251 – 500

Category 5: 501 – 1000

Category 6: > 1000

Data entry conversion for each macroinvertebrate category is as follows:

Category 1: 37

Category 2: 75

Category 3: 175

Category 4: 375

Category 5: 750

Category 6: 1001

The habitat complexity data is based on a six-point subjective assessment of topographical diversity and complexity of the benthic habitat. Classified according to 1 of 6 categories: low (L), medium-low (ML), medium (M), medium-high (MH), high (H), and very high (VH).

There are a few scenarios that will affect the completeness of the data:

-If the GPS points are not collected, associated diver's positions and survey tracks are not generated

-If the estimation of the divers' positions are erroneous and it is impossible to make corrections, the tow tracks/points are flagged and removed from further analyses

-If SEABIRD sensor (SB 39) is not operational during surveys, temperature and depth data are not available

The same methods of data collection are used during each tow. Regular examination and comparisons of the data are conducted throughout each mission to check for diver bias or other discrepancies.

The data is entered in an MS Access database, then quality controlled against the physical data sheets prior to the data being considered final. Several queries in the MS Access and Oracle databases flag any errors based on predefined criteria.

The data is captured in several locations: physical data sheets, MS Access cruise database, and PIFSC Oracle database. The physical data sheets are housed at PIFSC. The MS Access cruise database is regularly backed up by the cruise data manager while at sea. The PIFSC Oracle database is regularly backed up by PIFSC ITS.

Benthic towed-diver survey method