The Government of Guam's Long-term Coral Reef Monitoring Program, coordinated by the Guam Coastal Management Program until October 2013 and now coordinated by the University of Guam Marine Lab, involves the collection of data for a suite of coral reef ecosystem health parameters at several high priority reef sites around the island of Guam, including Tumon Bay, East Agana Bay, Piti Bay, and Western Shoals. Sites at Fouha Bay, the Achang Reef Flat Marine Preserve, and the Eastern seaward slope near Cocos Island will be established in 2014. Data are collected annually or biennially by a team of highly-trained field biologists from the Guam Coastal Management Program, the NOAA Pacific Islands Regional Office, the University of Guam Marine Lab, and with occasional assistance by staff from other agencies. Macroinvertebrates are culturally, economically, and ecologically important resources for the island of Guam. In recognition of the value and importance of this resource, macroinvertebrate surveys are a key component of the Guam Long-term Coral Reef Monitoring Program. Macroinvertebrate surveys have been conducted at high priority reef sites around Guam since August 2010. The surveys are carried out at numerous sampling stations within each monitoring site, the locations of which were generated randomly using a Geographic Information System and the relevant bathymetric and benthic habitat data. A split-panel approach is currently used for the sampling design, with half of all sampling stations in a given site being fixed and half re-randomized every visit or every other visit. The monitoring team counts the number of commercially and ecologically important macroinvertebrate species within a 4 m x 25 m belt transect at all stations (except at the Western Shoals stations, where 4 m x 15 m belts are used). The longest dimension of Tridacna individuals is also recorded. These monitoring data on macroinvertebrate communities provide results on macroinvertebrate density and diversity, allow for exploration of community structure by functional group; and can be used to detect changes in macroinvertebrate communities over time.
The macroinvertebrate belt transect data are collected as part of the Guam Long-term Coral Reef Monitoring Program, which documents a number of important parameters related to ecosystem health; these parameters are grouped into three categories: water quality, benthic habitat, and associated biological communities. Many of these parameters are indicators of stressors, and significant changes in these parameters will likely raise concern and possibly trigger management actions. Data collected for these indicators provide important information about the resilience of high priority reef areas around Guam. Monitoring these parameters allows resource managers to evaluate the effectiveness of specific management strategies, and inform the development of new management actions.
Macroinvertebrate belt transect surveys have been conducted since 2010 at: Tumon Bay from August 6 to September 3 2010 at 15 stations ranging in depth from 5 to 14 meters and from September 5 to November 7 2012 at 16 stations ranging in depth from 6 to 14 meters (but note that the site boundaries of the Tumon station changed between 2010 and 2012 and only a small number of fixed stations surveyed in 2010 were resurveyed in 2012). East Agana Bay from September 9 to November 26 2010 at 12 stations ranging in depth from 6 to 15 meters and from November 16 to November 28 2012 at 10 stations ranging in depth from 8 to 14 meters Western Shoals from July 11 to August 19 2011 at 23 stations ranging in depth from 2 to 18 meters. Piti from July 27 to August 31 2012 at 14 stations ranging in depth from 7 to 12 meters. Surveys were not conducted in 2013, and are currently in progress for 2014 (as of the publication date of this document).
Ground Condition
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.
Marine Laboratory - University of Guam
Marine Laboratry – University of Guam
Guam Coastal Management Program, NOAA Pacific Islands Regional Office, and University of Guam Marine Lab.
Observations at each site were made by divers who have been trained and met minimum standards in identifying species present at the survey locations. Species identification and counts were periodically checked for accuracy and consistency between divers, and little discrepancy was noted. The surveys are generally conducted by taxonomic experts, but when field technicians do not possess the requisite taxonomic expertise, photos of specimens that cannot be identified are provided to taxonomic experts for identification.
The same methods of data collection were used at each of the stations surveyed. Surveys were conducted by a team of scientists that met minimum qualifications and trained and calibrated together.
Only hard-bottom habitats are surveyed. Surveys have been conducted every year between 2010 and 2014, except for 2013. Data entry and quality control are complete for surveys conducted through 2012; 2014 surveys are in progress, and as such, data entry has not yet commenced (as of the publication date of this doucment).
5-10 meters as determined by GPS Unit Instrument parameters
Dive computer and analog SCUBA depth gauge
Instrument parameters
Macroinvertebrate belt transect surveys are carried out at most sampling stations. An attempt is made to carry out macroinvertebrate belt transects at all stations, but occasionally this survey may not be conducted due to staff/time constraints. All sampling stations have been selected in hard-bottom habitats using a stratified random sampling design, and the stations have been designed using the split-panel approach (combination of fixed and non-fixed transects). Each sampling station is located using a GPS receiver. Upon reaching a given station, a small weight and line tied to a buoy is carefully lowered to the ocean floor. In optimal situations where four divers are available, two divers enter the water first to carry out the fish surveys. Starting at the weight tied to the buoy, a 30-meter transect is laid out. The transect is laid out in a clockwise direction relative to the island, following the depth contour if it is readily determined; if the area is relatively flat and a depth contour is not readily discernable the transect is laid at an angle parallel to the reef margin (which is determined prior to entering the water). Compact digital point and shoot cameras and housings are used by individual observers to document unknown organisms, incidences of coral disease, and species/behaviors of special interest. For the initial establishment of fixed sampling stations, 24 inch rebar is installed at the beginning of the transect and 12 inch rebar is installed at the center and end of the transect; four-inch concrete nails are installed at two of the corners of each quadrat used for coral size and condition surveys. For the Western Shoals site, rebar and concrete nails were not used and instead a small PVC float was tied to dead coral with a line at the beginning of the transect and large zip ties were placed at the beginning, middle, and end of the transect. Two small zip ties were used to mark two corners of each permanent quadrat location. To minimize diver disruptions, the two divers conducting the benthic surveys enter the water approximately 20-30 minutes after the divers conducting the fish surveys, once the fish team has finished enumerating fish. In situations where only three divers are available, all three divers enter the water at the same time and remain as a three-person buddy team to ensure diver safety throughout the survey. A fish diver partners with a benthic diver when two fish divers are not available. In this situation, the fish diver lays the transect and conducts the first SPC at 22.5 m while the benthic diver works from 0-15 m; they then switch positions along the transect. The macroinvertebrate belt transect survey is usually carried out by the same person who carries out the benthic photo transect, but may be carried out by the coral quadrat diver or by a diver dedicated wholly to the macroinvertebrate survey. All commercially and ecologically important macroinvertebrates are counted within a 4 m x 25 m belt (4 m x 15 m belt at Western Shoals site) centered on the transect tape placed by the fish team. The diver carries out the survey by counting macroinvertebrates along one side of the transect tape (a 2 m belt) and returning along the other side (another 2 m belt), being careful not to double count species near the transect tape or which may have moved from one side to the other. A meter-long PVC pipe is used by the diver to ensure that their estimate of belt width is accurate. Macroinvertebrate taxa surveyed include echinoids, holothuroids, large crustaceans (e.g., Dardanus spp.), edible mollusks (Tridacna spp., Charonia tritonis, Trochus/Tectus spp., Lambis spp., Octopus spp.), large Actinarians (e.g., Heteractis spp., Entacmea quadricolor, Stichodactlya spp.) and the large corallimorpharian Amplexidiscus fenestrafer). Tridacna spp. are measured to the nearest centimeter.
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. The Guam Coastal Management Program makes no warranty, expressed or implied, nor does the fact of distribution constitute such a warranty.
Contact Guam Coastal Management Program Coordinator for information. Data are available in xls (Microsoft Excel worksheet) or csv (comma-separated values) format.
