At the beginning of the expedition, acoustic receiver buoys were deployed around the study site. These receivers are able to detect the individually-coded "pings" produced by acoustic tags on white sharks, allowing researchers to identify a specific individual shark when it comes within about 1,000 meters of a receiver. On the "abacus" plot below, individual sharks are represented by horizontal lines (the number is the code associated with each acoustic tag), and icons along those lines indicate the date on which that shark was detected. (For example, shark tag 19215 was detected on April 27, 2018).