Tracking of Sharks

Tracking marine animals has come a long way, from the use of conventional (or visual) tags, via acoustic tags and data loggers to today's state of the art satellite pop-up archival tags (PATs, see pictures). The latter may be attached to marine animals for extended periods of time; they store information on temperature, pressure and light levels, release themselves from the animal at a predetermined time, and then transmit all their data to satellites passing above, independent of a potential retrieval of the tags.

These features make them the ideal tool to study large pelagic predators like sharks or billfish, who may be highly migratory and remain constantly submerged, which rules out the regular transmission of real-time location data (i.e. GPS positions) to the satellites.

In a pilot project carried out this winter season we plan to fit 2 Oceanic Whitetip Sharks (Carcharhinus longimanus) with PATs, that will be attached for 1 and 3 months respectively. The data gained from these two individuals will provide the first insights into the sharks' diving behaviour and movement patterns in the Red Sea.

These results will help us to design a more extensive future tagging project, ultimately aiming at identifying critical habitat for the species, including major feeding areas, breeding and nursery grounds.