Designing an archival Satellite transmitter for life-long deployments on oceanic vertebrates: the life history transmitter

Despite the widespread use of sophisticated telemetry transmitters in behavioral, physiological and ecological studies, few studies on population dynamics of oceanic vertebrates use such technology, primarily due to the difficulty of obtaining multi-year records from individual animals. We present the first telemetry transmitter specifically designed for collecting vital data from marine vertebrates over extended periods, up to a decade. The implantable Life History Transmitter records data throughout the life of a host animal. After the host animal dies, the tag is extruded, and, while floating on the ocean or lying on a beach, transmits previously stored data to orbiting satellites. For tags relying solely on end-of-deployment transmission, reliability and proper recognition of tag state is crucial. The Life History Transmitter uses heuristic tag state determination, in combination with simple error detection and fault tolerance measures, to increase tag reliability and likelihood of data recovery. We used a computer simulation of tag deployments and various sensor failures on a PC platform, in combination with time-accelerated simulations running on the actual deployment platform, to test the functionality of fault tolerance and error detection protocols.