An acoustic micro-transmitter enabling tracking of sensitive aquatic species in riverine and estuarine environments

Conservation of aquatic species requires in-depth understanding of their movement and behavior and their interactions with man-made hydraulic structures. Acoustic telemetry is a primary method to remotely track in 3 dimensions (3D) aquatic animals implanted with transmitters. The transmitter's weight and size are the major limiting factors because the transmitter should not affect the animals' natural behavior. Here, we present an acoustic micro-transmitter that weighs 0.08 g in air, only 1/3 that of existing technologies. The transmitter offers a source level of 148 dB (reference: 1 mu Pa at 1 m) and a service life of 30 days at a 5-s transmission rate. Nearly 100% of tagged fish were detected in field studies, demonstrating the viability of this technology for studying species of early life stages. Information resulting from the use of this technology provides valuable insight for ecological and environmental policy making and resource management worldwide.