Autonomous Gliders for Real Time Passive Acoustic Remote Sensing

Mark Baumgartner and David Fratantoni, Woods Hole Oceanographic Institution

The aim of this project is to explore the capability for autonomous gliders to provide real time locations of marine mammals as part of the NEFSC's ongoing efforts to monitor and assess marine mammal stocks. The distribution and habitat features of Gulf of Maine marine mammals will be mapped along set transect lines in the study area using gliders equipped with instrumentation to (1) record low frequency baleen whale vocalizations, (2) detect, classify, and remotely report particular vocalizations of interest, and (3) measure high-frequency acoustic backscatter, chlorophyll fluorescence and oceanographic conditions. The acoustic data will be used to document the distribution of acoustically active marine mammals, and accompanying measurements will be used to characterize the oceanographic conditions in relation to acoustic activity. Simultaneous aerial surveys will be carried out by the NEFSC in conjunction with these transects, weather permitting, to verify the occurrence of whales. Additionally, a validation exercise will be conducted aboard the NOAA Ship Delaware II during its May 2010 large whale cruise. Continuous visual and acoustic observations will be made in the vicinity of profiling floats equipped with the same instrumentation as carried by the gliders to detect, classify, and report baleen whale calls. Concurrent observations will be carried out for 24-48 hours on two occasions to allow the reported acoustic detections to be compared to visual detections. The utility of these technologies will be evaluated and assessed in the light of its value to provide information to mariners on the locations of large whales as an expansion of NOAA's efforts to reduce large whale ship strike mortalities.