Reef Check is the largest international coral reef monitoring program involving recreational divers and marine scientist. The Reef Check network covers over 50 countries and territories throughout the world.
During a reef check, volunteers are monitoring a measured area of coral reef and count specific species of corals, fish, sea urchins and sea cucumbers in that area. The gathered information is then sent to the Reef Check organization for further analysis. These information reflect how healthy a reef is and by continuing surveys changes on a reef can be detected.