Geolocating Archival Tags keep track of important clues about the migration patterns of marine animals such as temperature (both inside the animal and outside in the water), salinity, depth, and light availability. These tags are useful for accurately recording the position of the tagged animal over time, utilizing an internal clock mechanism that compares the length of daylight with a record of day length around the globe. The tags also record sea temperature. Scientists compare this temperature to satellite records to finely focus the tagged animal's exact location. As with other archival tags, these must be recovered and their complexity makes them more expensive. Nevertheless, this technology gives scientists an edge in tracking the journeys of large pelagic animals under water.
Examples of Geolocating Archival Tags. (TOPP)