The streamlining is required to reduce drag so that the anchor will not be pulled out by the hydrodynamic forces and the stabilizing fins cause the body to move in a straight line, even though the attachment point to the body oscillates as the fish swims. This squib activates a knife-edge that cuts through the wire connecting the tag body to the fish, releasing it. The body is designed such that its average density is slightly less than seawater and so it will float to the surface over a period of several minutes to several hours, depending on the depth at which it is released. The distribution of weights within the body is such that it will float head upwards, so that when it reaches the surface the cable remnant sticks out of the water and serves as an antenna. The fins now serve as stabilizers keeping the body vertical even in a wavy environment, and a light sensor, activated when the squib was ignited, starts broadcast transmission of the data collected.
Transmission then continues until the batteries run out.