DETECTION OF YANGTZE FINLESS PORPOISES IN THE POYANG LAKE MOUTH AREA VIA PASSIVE ACOUSTIC DATA-LOGGERS - Biology, Evolution and Conservation of River Dolphins Within South America and Asia - page 351

Table 1. Details of buoy-based long-term acoustic observation deployed at Station C (see
Figure 1), and total porpoise detection duration (min) and presence ratio (%) during
each deploying period.

Start day End day Days Porpoise detection duration (min) Presence ratio (%)

Jun. 27 Jul. 25 29 7,727 19.4

Jul. 26 Aug. 28 34 3,148 6.6

Sep. 12 Sep. 28 17 4,536 19.5

Total 80 15,411 13.9

Figure 5. (a) The diurnal presence ratio of porpoises detected by the A-tag in each 1-hour time unit over
the entire observation period at Station C. (b) The number of ships detected by the A-tag in each 1-hour
time unit over the entire observation period at Station C. Matches between hollows of porpoise
presence ratio and ridges of ship number, are indicated by grey transparent panes.