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The Salish Sea encompasses the waters between southern British Columbia mainland coast, Vancouver Island, and Washington State. Its waters are used by commercial and recreational fishers, host shipping traffic to the major ports of Vancouver and Seattle, and is travelled frequently by local ferries. It is also an important habitat for many marine mammal species, including the endangered Southern Resident Killer Whale (Orcinus orca). Southern Resident Killer Whales use calls, whistles, and clicks to communicate and find prey. Human activities on the water may affect the marine acoustic environment by masking whale vocalizations, which in turn will negatively impact the ability of the whales to forage and socialize. A field study was conducted to measure acoustic transmission loss at various places in the Salish Sea. Sound signals simulating killer whale call elements were broadcast from different angles to a calibrated hydrophone. Results from the study showed that acoustic transmission loss is highly spatially variable in this area. We suggest that these observations are due to changes in oceanography conditions and ambient sound levels, which are important factors to consider when assessing impact on Southern Resident Killer Whales. [Work supported by the Oceans Protection Plan of the Government of Canada.]

Resolute Bay, a remote bay in the Canadian High Arctic to the north of Parry Channel, hosts diverse populations of marine mammals that migrate through the bay each year following food availability and/or oceanographic conditions. The changing climate combined with increasing anthropogenic activity in the Arctic make it important to create an ecosystem baseline from which to predict, understand, and monitor future changes. Passive underwater acoustic observations provide a non-invasive way to monitor marine mammal presence. Broadband noise (10 Hz to 48 kHz) was recorded by an Autonomous Marine Acoustic Recorder (AMAR) and marine mammal click detections were logged by two CPODs over a 5 month period from August to December 2013. Acoustic data were processed with click and tonal call detectors to determine marine mammal presence. Resolute Bay is ice-covered 10 months a year, leading to increased broadband ambient noise levels due to ice movement. During the short open-water period, vessel activity is common in the bay. The aim is to compare these two different ambient noise regimes and how they affect the effectiveness of passive acoustic marine mammal detections and tracking.