**8. Conclusion**

Sea turtles are ocean-wide, long-distance migrating reptiles that spend more than 95% of their time at sea. The study of migratory behavior is important to demographic studies, dynamics of marine ecosystem and conservation measures of these marine reptiles . Telemetry devices developed since the late 70's, enhancing our understanding of sea turtle migratory mechanism substantially. In addition to conventional satellite tags, directional radio and sonic telemetry and ultrasonic-pinger were also developed in 1980's. However, the low resolution and labor-intense efforts limited their developments. The retrievable device—TDR developed since 1980's enables us to interpret the diving behavior of sea turtle in great detail. With the advancement of computer technologies, the new generation of nonretrievable satellite tags allows more sensors add to the satellite tags, thus enhance the tag performance. The combination of the oceanographic instruments with the satellite telemetries allows researchers to conduct multi-disciplinary approach to study the sea turtle migratory behavior, both qualitatively and quantitatively. These approaches allow us to conduct proper conservation measures in the ocean. The miniature, high resolution and multi-function telemetry tags emerges the biologging concept and may bring new explanatory power to the field of behavioral ecology.
