Real-time passive acoustic monitoring results of the 2018 Pacific Region International Survey of Marine Megafauna off Western Canada

Abstract

Real-time passive acoustic monitoring (PAM) was conducted as part of the first large-scale systematic survey of marine mammal distribution and abundance in territorial outer-coastal waters off western Canada. The survey was conducted for approximately five weeks, from early July to mid-August, 2018 using a 69-m Canadian Coast Guard and Fisheries Vessel. A four-element, towed hydrophone array and sonobuoys (type AN/SSQ-53F and AN/SSQ-53G) were deployed and monitored in real-time 24/7 by experienced bio-acousticians. The towed array was deployed for approximately 640 h (78% of the time underway). Approximately 145 independent detections of marine mammals were made. Sperm whales (n = 53) and porpoises (n= 49) represented just over two-thirds of all detections. Ten near real-time localizations of sperm whales and 31 localization of porpoises were made, representing just over 60% of all (n = 67) all high-quality localizations. Sonobuoy effort consisted of semi-systematic deployments day and night and when sightings of large baleen whales occurred. A total of 112 sonobuoys were deployed successfully and monitored in directional (DIFAR) mode. Marine mammal calls were recorded on 32% (36) of sonobuoys. Sonobuoy detections included killer whales calls and clicks, sperm whale clicks, dolphin clicks, fin whale calls, and blue whale calls (both B and D type calls).