Pop-up Satellite Tags

Pop-up satellite tags are small devices that represent a marriage of archival tags and a satellite transmitter. The tag is inserted with a barb beneath the skin near the base of the dorsal fin (ideally) while the tag itself is outside the animal.

Satellite tag ready for deployment on a tagging staff.

White shark tagged below the dorsal fin with a pop-up satellite tag. photo credit Phillip Colla

These tags log temperature, depth and light intensity. As with the archival tags, light can be used to calculate latitude and longitude. After a predetermined amount of time, the tag releases from the fish, floats to the surface and uploads its data to the ARGOS satellite system. Because the satellites can only transfer 32 bytes of data at a time, the data must be compressed before transmission and detailed records like those provided by the archival tags are difficult to obtain. The data is then transferred via the internet to MCSI researchers.

Pop-up satellite tags allow us to follow the fish on its journey without ever having to get wet. We can examine behaviors and obtain estimates of the movements of the fish between the point the tag was deployed and the time the tag releases. The fish never has to be recaptured to recover the data and we can study species for which there is no fishery or for which conventional tag returns are very low. The only disadvantage of the pop-up tags is that they are relatively expensive and data transmission is limited.

MCSI uses pop-up satellite tags to track the movements of: