Researchers deploy baited cameras on the seafloor to monitor sharks, rays, and other animals. This setup is called a BRUV: baited remote underwater video. If sharks or rays are attracted to the scent emanating from the BRUV they will be caught on film. This enables researchers to measure how often sharks and rays are seen on each surveyed reef, which then allows for a comparison to different reefs all over the world. They can use mathematical models to figure out what features of a reef, such as how many fish live on it, how healthy its corals are, or whether or not it is closed to fishing, influence shark and ray abundance.