Real Time Assessment of Baleen Whale Occurance Using Moored Passive Acoustics
Passive acoustic monitoring is a vital part of NMFS’ mission to assess and manage marine mammal stocks, since it provides a persistent and cost effective complement to more traditional monitoring approaches (i.e., shipboard and aerial surveys). Recent advances in automated detection and classification techniques for low-frequency baleen whale calls have made real-time assessment from in-situ acoustic instrumentation feasible. We have been developing the capability to remotely detect and report a wide variety of calls produced by several species of baleen whales from autonomous platforms, including ocean gliders and profiling floats. We propose here to extend this capability by building a moored system that takes advantage of several existing technologies, including (1) the programmable DMON acoustic instrument, (2) the low-frequency detection and classification system (LFDCS), (3) a very low noise mooring design that incorporates a “stretch hose” to decouple the motion of the surface telemetry buoy from the acoustic instrument, and (4) a shore-side satellite receiving system and web server to disseminate acoustic detection data on the web in near real-time. The DMON instrument running the LFDCS will be suspended on the mooring line at depth, and real-time detection data will be transmitted from the DMON to a data logger in the surface buoy. The data logger will relay detection data to a shore-side computer via Iridium satellite communications every 6 hours, and these data will be immediately posted to a website in both graphical and tabular formats. After demonstrating this capability during this project, we envision that NMFS will apply this new technology to assessing the occurrence, distribution, calling behavior, and habitat of several species of endangered baleen whales in the northwest Atlantic Ocean, including right, sei, humpback, and fin whales. The flexibility of the mooring and the DMON/LFDCS will allow this system to be easily adapted to detecting the low-frequency calls of different species in other regions (e.g., blue and fin whales in the Pacific Ocean, bowhead whales in the Bering Sea and Arctic Ocean).