Development of geomagnetic field sensor loggers for global migration of marine lives.

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According to recent rapid development of microelectronics, we have epoch-making instruments to study behavior of marine biology. There are many kinds of data such as swimming depth, speed, acceleration, ambient temperature and body temperature to be acquired using micro. data-loggers, ultrasonic transmitters and satellite telemetry. In addition, we had developed telemetry to measure ECG_s of free-ranging. fish. In this study, we developed geomagnetic field sensor loggers to measure three-dimensional behaviors of marine lives under water.We developed some kinds of new data loggers which were combined geomagnetic field sensors and acceleration sensors. In 2000, we nufactured brand-new geomagnetic field sensor loggers which were combined with magneto-resistive sensors and acceleration sensors. We performed preliminary experiments in a rearing pond in Thailand both in 2000 and 2001 using rearing hawksbill turtles and green turtle. This preliminary experiment resulted that the new loggers could record heading direction of sea turtles and their flipper frequencies. Based on the results, we improved the loggers and performed an open sea trial in. the Andaman Sea in 2002 and 2003. The results realized the three-dimensional behavior of a green turtle under water.