Fig. 5

Depth use in the context of the physical and biological environment for a shark 1 and b shark 2. Shades of red indicate percentage of time per day spent in each 10-m-depth bin based on minutely time series. Thermocline limits mark the upper (10%) and lower (70%) extent of the thermocline. Circles show presence of bioluminescence events coloured by time of day (day: α ≥ 6°, twilight: − 6° < α > 6°, night α ≤ − 6°). Note free y-axes