How deep can baleen whales dive?

This paper presents evidence of deep diving performances by fin whales Balaenoptera physalus in the Mediterranean Sea, never directly recorded for any other species of baleen whales. By means of velocity-time-depthrecorders applied to the whales with suction cups, depths of at least 470 m were registered twice, over 7 dives below 150 m recorded during a total of 12 h 38 min of remote tracking. The deep bouts occurred in late afternoon, in coincidence with the die1 vertical upward migration of knll Meganyctiphanes norvegica, the principal prey species for Mediterranean fin whales. The data presented indicate that fin whale diving capabilities are opportunistically adapted to deep prey availability in the area.