Guam Long-term Coral Reef Monitoring Program Coral Colony Size and Condition Surveys since 2010

The Government of Guam's Comprehensive Long-term Monitoring at Permanent Sites in Guam project, also known as the Guam Long-term Coral Reef Monitoring Program (GLTMP), is a NOAA-funded project currently coordinated through the University of Guam Marine Laboratory. The program involves the regular, intensive collection of data for a suite of coral reef ecosystem health parameters at high priority reef areas (HPRAs) around Guam, as well as critical support for coral bleaching response and other activities carried out by the multi-partner Guam Coral Reef Response Team. The program currently utilizes a split-panel sampling approach, whereby a mix of permanent and non-permanent sampling stations (one sampling station = one transect) are visited within each HPRA. The HPRAs were selected by an advisory body comprised of reef managers, researchers, and technicians; these reef areas were not intended to be representative of Guam's reefs more broadly. The locations of the sampling stations within each HPRA are generated randomly using GIS software. Various coral reef surveys are carried out on an annual basis along the seaward slope between 7 and 15 m depth in the Tumon Bay Marine Preserve and in East Agana Bay, while surveys are carried out biennially within the Piti Bomb Holes Marine Preserve, the Achang Reef Flat Marine Preserve, and the eastern side of the Cocos Barrier Reef (Cocos-East). Surveys were also carried at along reef margin (1-2 m) and slope (2-15 m) of Western Shoals, in Apra Harbor, in 2011. The surveys, which are currently conducted by University of Guam Marine Laboratory biologists, and which were supported by NOAA PIRO through 2019, currently include benthic photo transects, stationary point count fish surveys, macroinvertebrate belt transects, and chain-length rugosity surveys. The GLTMP has conducted surveys at the Tumon and East Agana HPRAs since 2010, the Piti HPRA since 2012, and the Achang and Cocos-East HPRAs began in 2014. Surveys for Fouha Bay HPRA began in 2015 with data collections also occurring in 2019 and 2021, but the site has not been re-visited due to shifting management priorities. Baseline data is available for the Western Shoals HPRA from 2011 but this site has not been re-visited.

Corals are the main contributor to coral reef accretion, provide critical habitat for numerous reef organisms, and serve as a food source for some reef organisms. In recognition of the critical important of corals, coral colony size and condition surveys were carried out by the GLTMP at several HPRAs on a regular basis between 2010 and 2019. Nearly all of the coral quadrat surveys were carried out by a single observer. The size and condition are assessed for all coral colonies found within quadrats placed every 5 meters along 30-m transects (15-m transects for the Western Shoals HPRA, 25 m for other HPRAs prior to 2018). These monitoring data on coral communities provide results on coral colony density, size, condition, and diversity; allow for exploration of community structure by functional group and size; and can be used to detect changes in coral communities over time. The coral quadrat surveys were eliminated beginning in 2020 due to staff capacity limitations, but the nails marking the quadrat locations at some sampling stations have been been maintained opportunistically.

IMPORTANT NOTE: The plate-and-pillar coral, Porites rus, was excluded from the coral quadrat survey during the 2019 and 2020 field seasons due to the considerable time required to properly assess the size and condition of this abundant species and the limited availability of the program coordinator to carry out the specialized survey.

The stated goals of the Guam Long-term Coral Reef Monitoring Program (GLTMP) are to determine the status and trends of selected coral reef ecosystem indicators to inform resource managers' decision-making process, provide managers with early notice of abnormal conditions, provide data to better understand the dynamic nature of the island's coastal ecosystems, allow resource agencies to meet certain legal and Congressional mandates, and measure progress towards performance goals. Benthic cover data collected by the GLTMP at several High Priority Reef Areas around Guam provide documentation of the structure and condition of the benthic communities at these sites; data from multiple visits can be used in time series analyses to determine trends in key ecosystem parameters.

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The following FGDC sections are not currently supported in InPort, but were preserved and will be included in the FGDC export:

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Coral colony size and condition data have been collected since 2010 (with the noted exceptions below) in:

Tumon Bay in 2010 (10 permanent and 10 non-permanent stations), 2012 (12 permanent and 9 non-permanent stations), 2014 (12 permanent and 4 non-permanent stations), 2015 (12 permanent and 10 non-permanent stations), 2017 (12 permanent and 2 non-permanent stations), 2018 (4 permanent stations), 2019 (12 permanent stations).

East Agana Bay in 2010 (10 permanent and 10 non-permanent stations), 2012 (10 permanent stations), 2014 (10 permanent stations), 2015 (10 permanent stations), 2017 (10 permanent and 12 non-permanent stations), and 2019 (9 permanent stations).

Western Shoals in 2011 (11 permanent and 12 non-permanent stations)

Piti Bay in 2012 (10 permanent and 10 non-permanent stations), 2014 (10 permanent and 2 non-permanent stations), and 2017/18 (8 permanent stations).

Achang in 2014 (8 permanent and 3 non-permanent stations) and 2018 (9 permanent stations).

Cocos-East in 2018 (3 permanent stations).

Fouha Bay in 2015 (13 permanent stations) and 2019 (6 permanent stations).

Raw survey data includes metadata for each survey (where, when, who, area); site characteristics (depth, reef type, habitat, exposure); individual adult and juvenile coral observations identified to the lowest taxonomic level possible (usually species) including morphology, empirical size measurement, and all other recorded colony attributes including partial mortality and condition.

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, the University of Guam Marine Laboratory 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. The University of Guam Marine Laboratory makes no warranty, expressed or implied, nor does the fact of distribution constitute such a warranty.

Tumon Bay

East Agana Bay

Western Shoals

Piti (Tepungan) Bay

Achang

Cocos-East

Fouha Bay

Not applicable

Not applicable

Data can be accessed online via the NOAA National Centers for Environmental Information (NCEI) Ocean Archive or by contacting David Burdick at burdickd@triton.uog.edu.

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Please cite the Guam Coastal Management Program when using data collected prior to October 2013. Guam Coastal Management Program, Guam Bureau of Statistics and Plans, Government of Guam. Please cite the University of Guam Marine Laboratory when using data collected after (and including) October 2013.

Example citation:

For data collected from 2010 to 2012:

Guam Coastal Management Program (2019). Guam Long-term Coral Reef Monitoring Program Coral Colony Size and Condition Surveys since 2010. NOAA's National Center for Environmental Information, https://www.fisheries.noaa.gov/inport/item/47781.

For data collected after 2012:

University of Guam Marine Laboratory (2019). Guam Long-term Coral Reef Monitoring Program Coral Colony Size and Condition Surveys since 2010. NOAA's National Center for Environmental Information, https://www.fisheries.noaa.gov/inport/item/47781.

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None

Observations recorded on data sheets are entered into a data management website that populates a Microsoft SQL Server administered by the University of Guam.

Observations at each site were made by divers who have been trained, and met minimum standards in identifying species present at the survey locations and in assessing colony size and condition. Most data collected through 2019 were collected solely by the Monitoring Program Coordinator, but data for some sites were collected wholly or in part by one other skilled observer.

The vast majority of all coral colony and size observations to-date have been made by the Program Coordinator, with a limited amount of data collected by another coral survey specialist. Inter-observer bias is minimized through consistent training and calibration procedures.

Improvement over time in observers' general level of skill with the survey method, and an evolving understanding of the coral taxa at the monitoring sites, should be taken into account when comparing data across time; however, minor improvements in skill are not expected to have a significant impact on data quality. Comparisons of data across sites or across years must take into account differences in environmental and biological aspects of each site. Comparisons for a give site across time should consider any changes to the site boundaries over time. Please refer to the Extents section of this metadata record to see how the Tumon site boundaries shifted after 2010.

Only hard-bottom habitats are surveyed. Surveys are conducted annually to biennially for the Tumon and East Agana sites, but are conducted on a less frequent basis at other sites. In addition, while all permanent sampling stations are generally surveyed each sampling period, surveys are not always conducted at the full set of non-permanent stations for each site during each sampling period. It should also be noted that while five (prior to 2017) or six (after 2017) quadrats were surveyed for the vast majority of all sampling stations within all sites for each sampling period, in some instances there may be fewer quadrats for a given sampling station. Below is a summary of the number of permanent and non-permanent sampling stations surveyed each year for each site:

Tumon Bay: 2010 (10 perm, 10 non-perm); 2012 (12 perm, 9 non-perm); 2014 (12 perm, 4 non-perm); 2015 (12 perm, 10 non-perm); 2017 (12 perm, 2 non-perm); 2018 (4 perm, 0 non-perm); 2019 (12 perm, 0 non-perm)

East Agana Bay: 2010 (10 perm, 10 non-perm); 2012 (10 perm, 0 non-perm); 2014 (10 perm, 0 non-perm); 2015 (10 perm, 0 non-perm); 2017 (10 perm, 0 non-perm); 2018 (no coral quadrat data collected); 2019 (9 perm, 0 non-perm)

Western Shoals: 2011 (11 perm, 12 non-perm)

Piti Bay: 2012 (10 perm, 10 non-perm); 2014 (10 perm, 2 non-perm); 2017-2018 (8 perm, 0 non-perm)

Achang: 2014 (8 perm, 3 non-perm); 2018 (9 perm, 0 non-perm)

Cocos-East: 2014 (no coral quadrat data collected); 2018 (3 perm, 0 non-perm)

Fouha Bay: 2015 (13 perm); 2019 (6 perm)

Data entry and quality control are complete for data collected through 2019.

The same methods of data collection were used at each of the stations surveyed, with the exception of surveys at the Western Shoals and Fouha Bay sites, for which larger (1 m x 0.75 m) quadrats were used along 15 m transects. Species-level identifications and coral health assessments likely became more accurate over time, but minor improvements in skill are not expected to have a significant impact on data quality.

All observations entered into the database through the online data entry system are compared against observations recorded on the raw data sheet. Once all database records are verified the quality control process is marked as complete for all observations associated with a given station/sampling period. This process is currently carried out by the Program Coordinator or the full-time field technician. It should also be noted that the data management system employs hard and soft validation to minimize data entry errors.

University of Guam Marine Lab resources and assets

The Coral Colony Size and Condition (or Coral Quadrat) Survey methodology, employed by the Guam Long-term Coral Reef Monitoring Program since 2010