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Appendix B. A figure showing the variation in diel dive index at different latitudes for nine turtles.

FIG. B1. For nine turtles, the variation in diel dive index at different latitudes. This index is the amount of time spent diving in the night (local midnight +/- 3 hours) divided by the amount of time spent diving in the day (local midday +/- 3 hours). Thus a value of 1 indicates the same amount of diving between night and day, a value of <1 indicates more day time diving and a value >1 indicates more night time diving. This index showed a systematic change with latitude, being low south of 10°N, rising to higher values at mid latitudes, before declining at higher latitudes.