Results from a recovered pop-up satellite archival tag attached to a 6 m male whale shark (Rhincodon typus) off the Yucatan Peninsula, Mexico. Ambient temperature and depth data recorded by the tag are shown for the entire 31-day track (top). The fast Fourier transform-generated periodogram from an analysis of these same fine-scale depth data are also demonstrated (bottom). The high amplitude peak at 1 cycle per day is indicative of a significant diel rhythm in the vertical movements of this shark.

Submitted by John Tyminski,

Mote Marine Lab,

Center for Shark Research.