Fig. 1

TADpole configuration used for dolphin and shark trials viewed from below. The aluminum holster has Delrin guides to position it around the dorsal fin (Fig. 2). The pole has a valve cylinder at its base, attached to the holster. A pneumatic cylinder is mounted to the holster with its piston in line with the Delrin and metal rings press fit into the tag wings. A pusher, sleeved by a dart, is threaded into the piston. When the trailing edge of the dorsal fin is surrounded by the tag wings, it triggers the piston to push a dart through the rings and the dorsal fin (insert). The dart is retained by a press fit into the Delrin ring. The piston retracts the pusher, leaving the animal free to swim off with the tag