## 3 Results
### Vertical Activity  
PSATs transmitted \(>\)1200 d of depth and \(>\)1000 d of temperature data, respectively. Based on recovered time-series data for sharks 180, 356, 365 and 366, mean and minimum depths per day were significantly deeper during the day than at night (mean depth: day 34.2 m \(\pm\) 30.9, night 31.0 \(\pm\) 26.2; Mann-Whitney rank-sum test, U = 3.9877 \(\times\) 10\({}^{13}\), n\({}_{1}\) = 9,076,219, n\({}_{2}\) = 8,780,746, \(p\) \(<\) 0.0001); (minimum depth: day 16.0 m \(\pm\) 22.8, night 1.7 m \(\pm\) 6.2; Mann-Whitney rank-sum test, U = 132,774, n\({}_{1}\) = 8,780,746, n\({}_{2}\) = 9,076,219, \(p\) \(<\) 0.0001), while a significant difference between maximum depth per day and night could not be demonstrated (day 55.0 m \(\pm\) 34.79, night 55.36 \(\pm\) 41.51) (Mann-Whitney rank-sum test, U = 209,677, n\({}_{1}\) = 648, n\({}_{2}\) = 646, \(p\) \(<\) 0.966). In general, sharks were surface-oriented, spending, on average, 22% and 81% of their time in the top 10 m and 50 m, respectively. Yet, depth preferences varied among individual sharks (Figure S3) and among regions (Figure 2). Figure 2: **Depth and temperature occupation by latitudinal zones (north, central and south). ** Yellow dots represent positional data of all individual tracks (\(n\) = 12) displayed in Figure 1. (**A**,**B**) indicate percent time at depth and temperature by day (white bars) and night (grey bars) from Pop-Up Satellite Archival Transmitting tags (PSAT) data for each latitudinal zone. Error bars represent SDs. ‘IDs’ indicates the ID numbers of sharks for which depth and temperature records were included in each histogram. n\({}_{1}\) and n\({}_{2}\) indicate the number of depth and temperature records and the number of waypoints (points along estimated tracks) included in each histogram, respectively. Sharks for which depth or temperature data were missing for more than 25% of the total deployment days were excluded from the analyses. Red arrows indicate depth above which 95% of data occur for both day and night. Depth \(>\) 250 m were included into the 240–260 m bin. Temperatures \(<\) 12 \({}^{\circ}\)C were included into the 12–14 \({}^{\circ}\)C bin. For shark 180, all available depth and temperature data were included into the analysis, even though the full track of this shark is not shown in the zoomed-in map. The map was generated using the marmap package in R [37]. Three regional depth patterns were identifiable: Region 1--broad distribution between the surface and 100 m; Region 2--most time (mean 76%) was spent in shallow water <40 m; Region 3--bimodal distribution, most time (mean 27%) was spent at the surface (0-20 m), with a second mode at 40-80 m (mean 25%). Water temperatures spanned a 21.1 \({}^{\circ}\)C range from 7.8-28.9 \({}^{\circ}\)C. Temperature ranges traversed by sharks continuously decreased from Zone 1 (7.8\(-\)28.9 \({}^{\circ}\)C) to Zone 2 (9.2-24.3 \({}^{\circ}\)C) to Zone 3 (16.3\(-\)22.1 \({}^{\circ}\)C). Archival depth and temperature data sampled at 3-s intervals revealed distinct fine-scale oscillatory behaviours for sharks 180, 356, 365 and 366 throughout the deployment records. These individuals primarily stayed at relatively constant depths throughout the day, with limited vertical movements. At night, they continuously oscillated up and down through the water column (as reflected by a high coefficient of variation) (Figure 3). Similar patterns were also visible in the transmitted data from non-recovered tags, except for 4 sharks that had insufficient amounts of depth data transmitted. In shark 180, distinct intra- and inter-regional variations in fine-scale vertical behaviour were visible (Figure 4).