The whales are monitored in near real time using satellite telemetry provided by the Argos System. Once attached to the animals, transmitters begin sending radio signals at pre-scheduled times, and these signals are received by satellites, decoded and converted into geographic locations. The satellite then transmits this information to land stations, where the data are distributed to researchers.
Several types of transmitters supplied by Wildlife Computers have been used by the PMBS, and transdermal transmitters are currently used. These transmitters are referred to as ‘implantable’ because they penetrate the body of the whales and attach beneath the skin and the blubber layer. These transmitters have two main components: an anchoring system and electronics package. The anchoring system ensures transmitter attachment to the subcutaneous tissue of the animals, whereas the electronics package contains the components responsible for transmitter functions and signal conveyance to satellites.
The satellite transmitters are attached with a carbon fiber rod or compressed air rifle. The dorsal region of the whale is the most appropriate site for transmitter placement because it allows the transmitter to be exposed for longer periods of time, ensuring improved transmission quality. When the whales are submersed, the transmitter remains off. When the animals reach the surface, a sensor detects that the transmitter is exposed to air and activates the transmission. The radio signals are sent through an antenna located at the rear of the transmitter.