Licuanan, Wilfredo Y.Mordeno, Princess Zyrlyn B.Go, Marco V.2025-06-152021-09Licuanan, W. Y., Mordeno, P. Z. B., & Go, M. V. (2021). C30 — A simple, rapid, scientifically valid, and low-cost method for citizen-scientists to monitor coral reefs. <i>Regional Studies in Marine Science</i>, <i>47</i>, Article 101961.2352-485510.1016/j.rsma.2021.101961https://hdl.handle.net/20.500.14697/571We thank the Department of Science and TechnologyPhilippine Council for Agriculture, Aquatic and Natural Resources Research and Development (QMSR-MRRD-COR-0-1209 and PCAARRD-GIA 4478), and the Department of Environment and Natural Resources Coral Reef Visualization and Assessment, The Philippines Project for funding some of the fieldwork. The initial research on citizen-science monitoring was undertaken with funding from Oscar M. Lopez Center for Climate Change Adaptation and Disaster Risk Management Foundation, Inc., The Philippines (Grant number OMLC RG 2017-18). We also thank the DLSU Innovation and Technology Office for the patent application for the C30 monopod in the Intellectual Property Office of the Philippines. The comments and suggestions of the reviewers are acknowledged and are very much appreciated. WY Licuanan is the holder of the Br H Alfred Shields FSC Professorial Chair in Biology and Br Cresentius Richard Duerr FSC Professorial Chair in Biochemistry.The extent and speed of recent changes in reef coral abundances due to ocean warming and human impacts require more widespread capability to map and measure these changes, especially in countries like the Philippines. We present “C30”, a simple, rapid, scientifically valid, and low-cost method for skin divers or freedivers to take random photo-quadrat images within predefined stations on the upper reef slope. C30 yields coral cover data similar to those collected using the more intensive C5 method and can be as powerful in detecting small differences in reef cover. Less time is also needed for training personnel and sampling. However, more photo-quadrat images, better cameras, and closer collaboration with local scientists are required if higher precision data and estimates of coral diversity are needed from C30. C30 is a valuable tool for participatory, community-based citizen science monitoring of coral reefs.enCoral reefsCoral reefs and islandsCoral reefs and islands--Environmental aspectsArticleSDG 14 - Life below waterSDG 13 - Climate actioncoral reefsenvironmental monitoringChallenge 2: Protect and restore ecosystems and biodiversityChallenge 6: Increase community resilience to ocean hazards