How deep can baleen whales dive?

This paper presents evidence of deep diving performances by fin whales Bala enoptera physalus in the Mediterranean Sea, never directly recorded for any other species of baleen whales. By means of velocity-time-depth-recorders applied to the whales with suction cups, depths of at least 470 m were regi stered twice. over 7 dives below 150 m recorded during a total of 12 h 38 m in of remote tracking. The deep bouts occurred in late afternoon, in coinci dence with the diel vertical upward migration of krill Meganyctiphanes norv egica, the principal prey species for Mediterranean fin whales. The data pr esented indicate that fin whale diving capabilities are opportunistically a dapted to deep prey availability in the area.