Fully utilizing the acoustic record for biological monitoring and ecological applications

Abstract

Increasing demands to monitor marine ecosystems amplifies the need for efficient and effective characterization of organism abundances and distributions. Monitoring, processing, and archiving acoustic data may also be required in near-real-time when documenting environmental change or reporting impacts when meeting regulatory requirements. The Nekton Interactive Monitoring System (NIMS) is designed to address four challenges of ocean observation and monitoring: animal tracking, distribution characterization, regulatory thresholds, and data volume reduction. A Kalman filter is used to identify and link candidate targets into tracks. Backscatter measures are characterized using a suite of metrics (Sv, inertia, dispersion, Aggregation Index, evenness, % occupied) to quantify vertical distributions of pelagic organisms. If tracks cross pre-set exclusion ranges or regulatory thresholds of metrics are exceeded, then notifications are sent to trigger operational modification or mitigation. Kongsberg M3 sonar raw data acquisition rates of 11 Mb per second are reduced to 11 Mb per hour data storage, a 4 order of magnitude data savings. NIMS middleware can be deployed autonomously with instrument packages, remotely to telemeter data, network connected for real time monitoring, or used to process archived data. Example applications include ocean observatories and marine renewable energy environmental monitoring.