The reporting system will increase the value of the present Early Warning Network and overflights of the critical habitats by making all ships at sea aware of the whales' whereabouts. Both types of tags are dependent on batteries and the types of packaging and attachment devices employed. Most batteries can work for several months, but the attachment devices differ. Implanted tags, using devices that hook into the blubber, can stay for weeks or months. If the whale is underwater when the satellite is overhead, again no data.
Timing is the key.
In contrast, radio tags are used in more localized research. These tags have a line of sight coverage. The continuous signal can be heard by the researchers whenever the whale surfaces, allowing them to home in on the beep and track the whale. New multi-sensor VHS tags are able to collect a wide variety of data, all of which is stored in the tag package. After a certain length of time, the tag comes off the whale.