Designing a scalable passive acoustics network

To realize the potential of passive acoustics to study animal distribution and behavior over large spatial and temporal scales, systems capable of processing acoustic data remotely and transmitting those results to cloud systems are needed. Passive acoustic recorders have been important for allowing researchers to collect large amounts of data over long time periods, but they allow the decision of how to analyze the data to be delayed until after it is collected. Given the availability of inexpensive computing and cloud connectivity, one key challenge in developing a scalable passive acoustics network is deciding what is important to know. A prototype scalable passive acoustics node to detect dolphin whistles and measure sound levels corresponding to fish sounds, boat noise, and snapping shrimp has been developed. The decision was made to bin data over 10 minute periods (e.g., whistles per 10 minutes), and store only small amounts of raw data for quality control. The system takes advantage of recent developments in consumer level Internet of Things (IoT) tools so that the hardware is inexpensive and the cloud system can handle very large numbers of nodes.