This paper proposes advanced methodologies for the study of tagged marine animals, resorting to telemetry techniques. The robotic tools to be developed and operated will be able to track the acoustic signals emitted by the animals, based on range and depth data acquired with ultra-short baseline positioning (USBL) systems aided Inertial Navigation Systems (INS). The USBL is composed of an array of hydrophones with a pre-specified structure and the INS is based on the numerically integrated measurements from triads of low cost accelerometers, rate-gyroscopes, and magnetometers, complemented with data from depth cells. The preliminary design and implementation phases will be described and the results obtained to validate the proposed approach will be presented. Finally, the next development and validation phases will be briefly outlined.