Digital Acoustic Recording Tag (D-Tag)

Digital acoustic recording tags (D-TAGs) were developed by engineers, oceanographers and marine mammal biologists to monitor the behavior of marine mammals. The United States Office of Naval Research funded the development of the device in hopes of determining how marine mammals respond to sonar and other anthropogenically produced sound in the marine environment.

D-TAGs are a self-contained device that can record the pitch, roll, directionality, depth, and acoustics of marine mammals. D-TAGs are applied to the animal using an extendable, carbon-fiber pole (Photo 2, 5) and a cradle (Photo 1) that holds the tag. There are suction cups (Photo 3) on the base of the device that are specifically designed to adrere to marine mammal skin. The suction cups are released at a predesignated time. When a timer releases the suction cups, the device floats to the surface. The D-TAG floats vertically so that the antenna  (Photo 1) is out of the water. The device produces a VHF signal that can be tracked by using radio telemetry.

D-TAGs have 6.6 GBs capacity to store data. The data is retrieved using infra-red transmission.