Spatially balanced cluster design master sample for COTS and coral monitoring in the Great Barrier Reef

This data was produced as part of a COTS Control Innovation Program (CCIP) Translation project. The master sample is a spatially balanced sample of clusters of reefs where clusters have a 25km radius. The samples are stratified by Australian Institute of Marine Science (AIMS) Long Term Monitoring Program (LTMP) sector to ensure adequate representation across the reef. Within each sector clusters should be selected in order and reefs within those clusters should also be selected within order. The design requires the first logistically feasible reefs within each cluster to be monitored, if a reef is not able to be monitored for operational reasons eg. depth, crocodile risk, water visibility then the next reef on the list in that cluster should be selected. If a whole cluster is deemed an operational risk then the next cluster should be selected. \nLineage: The baseline monitoring master sample was developed through a multi-stage process balancing statistical rigor with operational feasibility for Great Barrier Reef-wide Crown-of-thorns Starfish monitoring. An initial spatially balanced cluster design was generated at the GBR level to optimise statistical efficiency. Following a stakeholder workshop with representatives from the Great Barrier Reef Marine Park Authority, Queensland Parks and Wildlife Service, and AIMS researchers, this was refined using a stratified approach based on AIMS Long-term Monitoring Program sectors. An oversample of clusters and reefs was generated for each of the 11 AIMS LTMP sectors to create the master list, with 1-2 clusters of three reefs targeted per sector. Duplicate reefs selected in multiple clusters were removed during this process.\nThe project team conducted systematic feasibility assessments of each cluster and reef in collaboration with COTS Control Program managers, Reef Joint Field Management Program field crews, and AIMS technical staff. Assessments evaluated safety considerations, weather dependencies, cultural sensitivities, physical constraints, and temporal restrictions. Based on these assessments, reefs posing unacceptable safety risks were removed and replacement reefs were selected sequentially from the master list within the appropriate sector. This iterative process resulted in the selection of 22 clusters (66 reefs) for baseline monitoring implementation.\nThe master sample list contains the selected reefs plus backup reefs and backup clusters in sequential order to support adaptive management while maintaining spatial balance properties. Any future reef or cluster substitutions must proceed sequentially through the master list within each AIMS sector to preserve the statistical validity of the design.