Fig. 4

During exposed dives with received sound pressure levels above 100 dB re 1 µPa for more than three min (n = 10), all whales showed a clear response to sonar sounds, i.e., an earlier B-onset time. The plot shows the received sound pressure levels (SPL, in dB re 1 µPa) of each sonar ping for each of the 16 dives performed by nine individual whales from four beaked whale species exposed to controlled sonar. Each subplot corresponds to a specific whale and dive, with the tag ID and dive number indicated in the title. The tag ID format includes species initials, year (two digits), Julian day, and tag deployment letter. Sonar pings are represented by different symbols indicating the dive type and dive phase in which the sonar ping was heard: downward triangles (shallow dive descent), upward triangles (shallow dive ascent), circles (deep dive descent), and crosses (deep dive ascent). Symbols are coloured red if no B-strokes were detected during that ping interval, or blue if at least one B-stroke occurred. The B-onset time is indicated by a dashed blue line. Note that some dives show B-strokes without a defined B-onset, as B-onset time is estimated as the elapsed time from the beginning of each dive until the first minute with at least the median ascent rate of B-strokes for each whale. SPL values are plotted for up to 11 min of each dive for ease of visualization. Each subplot includes markers for 100 dB re 1 µPa SPL and three min (i.e., a black horizontal line and a black vertical line, respectively) since the start of sonar for easy reference. For a detailed description of B-stroke occurrence in response to sonar, see Table S2.