After almost ten days of missing data, we finally received a tiny “blip” of data from Katia. During one of the transmission windows yesterday, her tag sent a small packet of data which likely means the tag is still attached to her. The satellite only received a single short transmission and was unable to compute a location for Katia.
The tag that she is towing is a type of pop-up archival transmitting tag (PAT tag, or PSAT). It is a sophisticated combination of archival/ GPS and Argos satellite technology. This type of tag was designed and programmed to track the large-scale movements of Katia. While the tag is attempting to send data every two days, it is primarily designed to detect mortality events. The tag has a very smart set of sensors and a micro controller on board to detect unexpected behavior such as mortality. If the tag detects that Katia has been submerged too long it will initiate a release and “pop up” to the surface to relay a subset of its collected data. Likewise, if the tag is pulled off Katia, it will detect that it has been at the surface too long and send data via satellite. There is also a small release device that will release the tag if it goes deeper than 2,000 meters.
Data transmitted at premature release:
- Light-based Geolocation
- Depth/Temperature Time-Series
- Diving Behavior
- Temperature Profiles
- Mortality Detection