A Sonic/Radio Tag for Monitoring Dive Depths and Underwater Movements of Whales

There has been much speculation about the ecology and behavior of whales, largely because effective techniques were not available for tracking them underwater, or for recording their dive depths. Thus, I developed a new tag and used it to mark free-swimming whales to monitor and record their geographical and vertical movements in real time. The tag contained 2 transmitters. The sonic transmitter (50 kHz) allowed submerged whales to be tracked from ≤2 km, and it produced a pulse rate or pulse intervalcoded signal from which dive depths were recorded. A VHF radio transmitter (148.00 MHz band) allowed individuals to be tracked at the sea surface from 10's of km