The data in this package include fish abundance, length, biomass, and presence/absence data collected at High Priority Reef Areas (HPRA) by Guam Long-term Coral Reef Monitoring Program (GLTMP) biologists. The monitoring team uses a Stationary Point Count Method, adapted from Ault et al. (2006) and NOAA Fisheries, Coral Reef Ecosystem Division (Williams et al., 2011), to conduct the reef fish surveys.

These data were collected using a split-panel sampling approach, whereby a mix of permanent and non-permanent sampling stations (one sampling station = one transect) were visited within each HPRA. The HPRAs were selected by an advisory body comprised of reef managers, researchers, and technicians. The sites were not selected randomly from around the island and thus should not be considered representative of reef condition at the island-scale. While the general location of the HPRAs were selected based on management priority, the site boundaries were delineated using bathymetry and benthic habitat data within ArcGIS and the locations of the sampling stations were generated randomly within each site’s boundaries using ArcGIS. The reef fish SPC surveys, as well as benthic photo transect, macroinvertebrate belt transect, coral quadrat (through 2019), and rugosity surveys were 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 were carried out biennially within the Piti Bomb Holes Marine Preserve, the Achang Reef Flat Marine Preserve, the eastern side of the Cocos Barrier Reef (Cocos-East), and Fouha Bay. 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 GLTMP has conducted surveys at the Tumon and East Agana HPRAs since 2010 and the Piti HPRA since 2012. Data collection for the Achang and Cocos-East HPRAs began in 2014 and at the Fouha Bay HPRA in 2015. Baseline data is available for the Western Shoals HPRA from 2011 but this site has not been re-visited since its establishment due to shifting management priorities.

IMPORTANT NOTE: Changes have been made to the fish SPC survey methodology since its first deployment in 2010. These changes, which are documented in detail in the Data Quality and Lineage sections of the NOAA InPort metadata record, must be considered in order to properly analyze these data. Also, please note that the results of a 2020 analysis of the fish SPC data conducted by Dr. Peter Houk of the University of Guam Marine Laboratory, and a 2023 analysis carried out by the GLTMP coordinator, found significant interobserver biases that must be taken into account during any analysis of these data. Dr. Houk's analysis also suggested that data collected in 2010 and 2011 by a relatively inexperienced observer did not meet quality assurance standards. Observations recorded by this observer were not included in the dataset submitted to NCEI; however, these data can be made available upon request. More information regarding the accuracy, bias, and comparability of these data can be found in the InPort metadata record.